Kevin Covey - Western Washington

Kevin Covey
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Name
Kevin Covey
Affiliation
Western Washington
City
Los Angeles
Country
United States

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Solar and Stellar Astrophysics (41)
 
Astrophysics of Galaxies (10)
 
Earth and Planetary Astrophysics (8)
 
Instrumentation and Methods for Astrophysics (4)

Publications Authored By Kevin Covey

2017May
Affiliations: 1Instituto de Astronomía, UNAM, Ensenada, BC, México, 2Centro de Investigaciones de Astronomía, Mérida, Venezuela, 3Instituto de Astronomía, UNAM, Ensenada, BC, México, 4Department of Physics & Astronomy, Western Washington University, Bellingham WA, USA, 5Instituto de Astronomía, UNAM, Ensenada, BC, México, 6Instituto de Astronomía, UNAM, Ensenada, BC, México, 7European Southern Observatory, München, Germany, 8Department of Physics & Astronomy, Vanderbilt University, Nashville, TN, USA, 9Cerro Tololo Interamerican Observatory, La Serena, Chile

The Orion OB1a sub-association is a rich low mass star (LMS) region. Previous spectroscopic studies have confirmed 160 LMSs in the 25 Orionis stellar group (25 Ori), which is the most prominent overdensity of Orion OB1a. Nonetheless, the current census of the 25 Ori members is estimated to be less than 50% complete, leaving a large number of members to be still confirmed. Read More

We analyze {\it K2} light curves for 794 low-mass ($1 > M_* > 0.1$ $M_{\odot}$) members of the $\approx$650-Myr-old open cluster Praesepe, and measure rotation periods ($P_{rot}$) for 677 of these stars. We find that half of the rapidly rotating $>$0. Read More

2017Feb
Authors: Michael R. Blanton, Matthew A. Bershady, Bela Abolfathi, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Javier Alonso-García, Friedrich Anders, Scott F. Anderson, Brett Andrews, Erik Aquino-Ortíz, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Kathleen A. Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Dominic Bates, Falk Baumgarten, Julian Bautista, Rachael Beaton, Timothy C. Beers, Francesco Belfiore, Chad F. Bender, Andreas A. Berlind, Mariangela Bernardi, Florian Beutler, Jonathan C. Bird, Dmitry Bizyaev, Guillermo A. Blanc, Michael Blomqvist, Adam S. Bolton, Médéric Boquien, Jura Borissova, Remco van den Bosch, Jo Bovy, William N. Brandt, Jonathan Brinkmann, Joel R. Brownstein, Kevin Bundy, Adam J. Burgasser, Etienne Burtin, Nicolás G. Busca, Michele Cappellari, Maria Leticia Delgado Carigi, Joleen K. Carlberg, Aurelio Carnero Rosell, Ricardo Carrera, Brian Cherinka, Edmond Cheung, Yilen Gómez Maqueo Chew, Cristina Chiappini, Peter Doohyun Choi, Drew Chojnowski, Chia-Hsun Chuang, Haeun Chung, Rafael Fernando Cirolini, Nicolas Clerc, Roger E. Cohen, Johan Comparat, Luiz da Costa, Marie-Claude Cousinou, Kevin Covey, Jeffrey D. Crane, Rupert A. C. Croft, Irene Cruz-Gonzalez, Daniel Garrido Cuadra, Katia Cunha, Guillermo J. Damke, Jeremy Darling, Roger Davies, Kyle Dawson, Axel de la Macorra, Nathan De Lee, Timothée Delubac, Francesco Di Mille, Aleks Diamond-Stanic, Mariana Cano-Díaz, John Donor, Juan José Downes, Niv Drory, Hélion du Mas des Bourboux, Christopher J. Duckworth, Tom Dwelly, Jamie Dyer, Garrett Ebelke, Daniel J. Eisenstein, Eric Emsellem, Mike Eracleous, Stephanie Escoffier, Michael L. Evans, Xiaohui Fan, Emma Fernández-Alvar, J. G. Fernandez-Trincado, Diane K. Feuillet, Alexis Finoguenov, Scott W. Fleming, Andreu Font-Ribera, Alexander Fredrickson, Gordon Freischlad, Peter M. Frinchaboy, Lluís Galbany, R. Garcia-Dias, D. A. García-Hernández, Patrick Gaulme, Doug Geisler, Joseph D. Gelfand, Héctor Gil-Marín, Bruce A. Gillespie, Daniel Goddard, Violeta Gonzalez-Perez, Kathleen Grabowski, Paul J. Green, Catherine J. Grier, James E. Gunn, Hong Guo, Julien Guy, Alex Hagen, ChangHoon Hahn, Matthew Hall, Paul Harding, Sten Hasselquist, Suzanne L. Hawley, Fred Hearty, Jonay I. Gonzalez Hernández, Shirley Ho, David W. Hogg, Kelly Holley-Bockelmann, Jon A. Holtzman, Parker H. Holzer, Joseph Huehnerhoff, Timothy A. Hutchinson, Ho Seong Hwang, Héctor J. Ibarra-Medel, Gabriele da Silva Ilha, Inese I. Ivans, KeShawn Ivory, Kelly Jackson, Trey W. Jensen, Jennifer A. Johnson, Amy Jones, Henrik Jönsson, Eric Jullo, Vikrant Kamble, Karen Kinemuchi, David Kirkby, Francisco-Shu Kitaura, Mark Klaene, Gillian R. Knapp, Jean-Paul Kneib, Juna A. Kollmeier, Ivan Lacerna, Richard R. Lane, Dustin Lang, David R. Law, Daniel Lazarz, Jean-Marc Le Goff, Fu-Heng Liang, Cheng Li, Hongyu LI, Marcos Lima, Lihwai Lin, Yen-Ting Lin, Sara Bertran de Lis, Chao Liu, Miguel Angel C. de Icaza Lizaola, Dan Long, Sara Lucatello, Britt Lundgren, Nicholas K. MacDonald, Alice Deconto Machado, Chelsea L. MacLeod, Suvrath Mahadevan, Marcio Antonio Geimba Maia, Roberto Maiolino, Steven R. Majewski, Elena Malanushenko, Viktor Malanushenko, Arturo Manchado, Shude Mao, Claudia Maraston, Rui Marques-Chaves, Karen L. Masters, Cameron K. McBride, Richard M. McDermid, Brianne McGrath, Ian D. McGreer, Nicolás Medina Peña, Matthew Melendez, Andrea Merloni, Michael R. Merrifield, Szabolcs Meszaros, Andres Meza, Ivan Minchev, Dante Minniti, Takamitsu Miyaji, Surhud More, John Mulchaey, Francisco Müller-Sánchez, Demitri Muna, Ricardo R. Munoz, Adam D. Myers, Preethi Nair, Kirpal Nandra, Janaina Correa do Nascimento, Alenka Negrete, Melissa Ness, Jeffrey A. Newman, Robert C. Nichol, David L. Nidever, Christian Nitschelm, Pierros Ntelis, Julia E. O'Connell, Ryan J. Oelkers, Audrey Oravetz, Daniel Oravetz, Zach Pace, Nelson Padilla, Nathalie Palanque-Delabrouille, Pedro Alonso Palicio, Kaike Pan, Taniya Parikh, Isabelle Pâris, Changbom Park, Alim Y. Patten, Sebastien Peirani, Marcos Pellejero-Ibanez, Samantha Penny, Will J. Percival, Ismael Perez-Fournon, Patrick Petitjean, Matthew M. Pieri, Marc Pinsonneault, Alice Pisani, Radosław Poleski, Francisco Prada, Abhishek Prakash, Anna Bárbara de Andrade Queiroz, M. Jordan Raddick, Anand Raichoor, Sandro Barboza Rembold, Hannah Richstein, Rogemar A. Riffel, Rogério Riffel, Hans-Walter Rix, Annie C. Robin, Constance M. Rockosi, Sergio Rodríguez-Torres, A. Roman-Lopes, Carlos Román-Zúñiga, Margarita Rosado, Ashley J. Ross, Graziano Rossi, John Ruan, Rossana Ruggeri, Eli S. Rykoff, Salvador Salazar-Albornoz, Mara Salvato, Ariel G. Sánchez, David Sánchez Aguado, José R. Sánchez-Gallego, Felipe A. Santana, Basílio Xavier Santiago, Conor Sayres, Ricardo P. Schiavon, Jaderson da Silva Schimoia, Edward F. Schlafly, David J. Schlegel, Donald P. Schneider, Mathias Schultheis, William J. Schuster, Axel Schwope, Hee-Jong Seo, Zhengyi Shao, Shiyin Shen, Matthew Shetrone, Michael Shull, Joshua D. Simon, Danielle Skinner, M. F. Skrutskie, Anže Slosar, Verne V. Smith, Jennifer S. Sobeck, Flavia Sobreira, Garrett Somers, Diogo Souto, David V. Stark, Keivan Stassun, Fritz Stauffer, Matthias Steinmetz, Thaisa Storchi-Bergmann, Alina Streblyanska, Guy S. Stringfellow, Genaro Suárez, Jing Sun, Nao Suzuki, Laszlo Szigeti, Manuchehr Taghizadeh-Popp, Baitian Tang, Charling Tao, Jamie Tayar, Mita Tembe, Johanna Teske, Aniruddha R. Thakar, Daniel Thomas, Benjamin A. Thompson, Jeremy L. Tinker, Patricia Tissera, Rita Tojeiro, Hector Hernandez Toledo, Sylvain de la Torre, Christy Tremonti, Nicholas W. Troup, Octavio Valenzuela, Inma Martinez Valpuesta, Jaime Vargas-González, Mariana Vargas-Magaña, Jose Alberto Vazquez, Sandro Villanova, M. Vivek, Nicole Vogt, David Wake, Rene Walterbos, Yuting Wang, Benjamin Alan Weaver, Anne-Marie Weijmans, David H. Weinberg, Kyle B. Westfall, David G. Whelan, Vivienne Wild, John Wilson, W. M. Wood-Vasey, Dominika Wylezalek, Ting Xiao, Renbin Yan, Meng Yang, Jason E. Ybarra, Christophe Yèche, Nadia Zakamska, Olga Zamora, Pauline Zarrouk, Gail Zasowski, Kai Zhang, Gong-Bo Zhao, Zheng Zheng, Zhi-Min Zhou, Guangtun B. Zhu, Manuela Zoccali, Hu Zou

We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratio in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially-resolved spectroscopy for thousands of nearby galaxies (median redshift of z = 0. Read More

2017Feb
Affiliations: 1Department of Astronomy, University of Florida, 2Department of Astronomy, University of Florida, 3Western Washington University, 4University of Oxford, 5Yale, 6Department of Astronomy, University of Florida, 7Leiden Observatory, 8Steward Observatory, 9University of Michigan, 10University of Michigan, 11Vanderbilt University, 12University of Virginia, 13Wesleyan University, 14University of Virginia, 15University of Virginia, 16University of Virginia

The kinematics and dynamics of young stellar populations tests theories of their formation. With this aim, we continue our analysis of the SDSS-III/APOGEE INfrared Spectra of Young Nebulous Clusters (IN-SYNC) survey, a high resolution near infrared spectroscopic survey of young clusters. We focus on the Orion A star-forming region, for which IN-SYNC obtained spectra of ~2700 stars. Read More

Ages and masses of young stars are often estimated by comparing their luminosities and effective temperatures to pre-main sequence stellar evolution tracks, but magnetic fields and starspots complicate both the observations and evolution. To understand their influence, we study the heavily-spotted weak-lined T-Tauri star LkCa 4 by searching for spectral signatures of radiation originating from the starspot or starspot groups. We introduce a new methodology for constraining both the starspot filling factor and the spot temperature by fitting two-temperature stellar atmosphere models constructed from Phoenix synthetic spectra to a high-resolution near-IR IGRINS spectrum. Read More

We present the results of a spectroscopic survey to characterize chromospheric activity, as measured by H$\alpha$ emission, in low-mass members of the 500-Myr-old open cluster M37. Combining our new measurements of H$\alpha$ luminosities ($L_{H\alpha}$) with previously cataloged stellar properties, we identify saturated and unsaturated regimes in the dependence of the $L_{H\alpha}$-to-bolometric-luminosity ratio, $L_{H\alpha}/L_{bol}$, on the Rossby number $R_o$. All rotators with Ro smaller than 0. Read More

2016Aug
Authors: SDSS Collaboration, Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Friedrich Anders, Scott Anderson, Brett H. Andrews, Alfonso Aragon-Salamanca, Maria Argudo-Fernandez, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Beatriz Barbuy, Kat Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Sarbani Basu, Dominic Bates, Giuseppina Battaglia, Falk Baumgarten, Julien Baur, Julian Bautista, Timothy C. Beers, Francesco Belfiore, Matthew Bershady, Sara Bertran de Lis, Jonathan C. Bird, Dmitry Bizyaev, Guillermo A. Blanc, Michael Blanton, Michael Blomqvist, Adam S. Bolton, J. Borissova, Jo Bovy, William Nielsen Brandt, Jonathan Brinkmann, Joel R. Brownstein, Kevin Bundy, Etienne Burtin, Nicolas G. Busca, Hugo Orlando Camacho Chavez, M. Cano Diaz, Michele Cappellari, Ricardo Carrera, Yanping Chen, Brian Cherinka, Edmond Cheung, Cristina Chiappini, Drew Chojnowski, Chia-Hsun Chuang, Haeun Chung, Rafael Fernando Cirolini, Nicolas Clerc, Roger E. Cohen, Julia M. Comerford, Johan Comparat, Marie-Claude Cousinou, Kevin Covey, Jeffrey D. Crane, Rupert Croft, Katia Cunha, Luiz da Costa, Gabriele da Silva Ilha, Jeremy Darling, James W. Davidson Jr., Kyle Dawson, Nathan De Lee, Axel de la Macorra, Sylvain de la Torre, Alice Deconto Machado, Timothee Delubac, Aleksandar M. Diamond-Stanic, John Donor, Juan Jose Downes, Niv Drory, Helion du Mas des Bourboux, Cheng Du, Tom Dwelly, Garrett Ebelke, Arthur Eigenbrot, Daniel J. Eisenstein, Yvonne P. Elsworth, Eric Emsellem, Michael Eracleous, Stephanie Escoffier, Michael L. Evans, Jesus Falcon-Barroso, Xiaohui Fan, Ginevra Favole, Emma Fernandez-Alvar, J. G. Fernandez-Trincado, Diane Feuillet, Scott W. Fleming, Andreu Font-Ribera, Gordon Freischlad, Peter Frinchaboy, Hai Fu, Yang Gao, D. A. Garcia-Hernandez, Ana E. Garcia Perez, Rafael A. Garcia, R. Garcia-Dias, Patrick Gaulme, Junqiang Ge, Douglas Geisler, Hector Gil Marin, Bruce Gillespie, Leo Girardi, Daniel Goddard, Yilen Gomez Maqueo Chew, Violeta Gonzalez-Perez, Kathleen Grabowski, Paul Green, Catherine J. Grier, Thomas Grier, Hong Guo, Julien Guy, Alex Hagen, Matt Hall, Paul Harding, R. E. Harley, Sten Hasselquist, Suzanne Hawley, Christian R. Hayes, Fred Hearty, Saskia Hekker, Hector Hernandez Toledo, Shirley Ho, David W. Hogg, Kelly Holley-Bockelmann, Jon A. Holtzman, Parker H. Holzer, Jian Hu, Daniel Huber, Timothy Alan Hutchinson, Ho Seong Hwang, Hector J. Ibarra-Medel, Inese I. Ivans, KeShawn Ivory, Kurt Jaehnig, Trey W. Jensen, Jennifer A. Johnson, Amy Jones, Eric Jullo, T. Kallinger, Karen Kinemuchi, David Kirkby, Mark Klaene, Jean-Paul Kneib, Juna A. Kollmeier, Ivan Lacerna, Richard R. Lane, Dustin Lang, Pierre Laurent, David R. Law, Jean-Marc Le Goff, Alexie Leauthaud, Cheng Li, Ran Li, Chen Li, Niu Li, Fu-Heng Liang, Yu Liang, Marcos Lima, Lihwai Lin, Lin Lin, Yen-Ting Lin, Dan Long, Sara Lucatello, Nicholas MacDonald, Chelsea L. MacLeod, J. Ted Mackereth, Suvrath Mahadevan, Marcio Antonio-Geimba Maia, Roberto Maiolino, Steven R. Majewski, Olena Malanushenko, Nicolas Dullius Mallmann, Arturo Manchado, Claudia Maraston, Rui Marques-Chaves, Inma Martinez Valpuesta, Karen L. Masters, Savita Mathur, Ian D. McGreer, Andrea Merloni, Michael R. Merrifield, Szabolcs Meszaros, Andres Meza, Andrea Miglio, Ivan Minchev, Karan Molaverdikhani, Antonio D. Montero-Dorta, Benoit Mosser, Demitri Muna, Adam Myers, Preethi Nair, Kirpal Nandra, Melissa Ness, Jeffrey A. Newman, Robert C. Nichol, David L. Nidever, Christian Nitschelm, Julia O'Connell, Audrey Oravetz, Nelson Padilla, Nathalie Palanque-Delabrouille, Kaike Pan, John Parejko, Isabelle Paris, John A. Peacock, Sebastien Peirani, Marcos Pellejero-Ibanez, Samantha Penny, Will J. Percival, Jeffrey W. Percival, Ismael Perez-Fournon, Patrick Petitjean, Matthew Pieri, Marc H. Pinsonneault, Alice Pisani, Francisco Prada, Abhishek Prakash, Natalie Price-Jones, M. Jordan Raddick, Mubdi Rahman, Anand Raichoor, Sandro Barboza Rembold, A. M. Reyna, James Rich, Hannah Richstein, Jethro Ridl, Rogerio Riffel, Rogemar A. Riffel, Hans-Walter Rix, Annie C. Robin, Constance M. Rockosi, Sergio Rodriguez-Torres, Thaise S. Rodrigues, Natalie Roe, A. Roman Lopes, Carlos Roman-Zuniga, Ashley J. Ross, Graziano Rossi, John Ruan, Rossana Ruggeri, Jessie C. Runnoe, Salvador Salazar-Albornoz, Mara Salvato, Ariel G. Sanchez, Sebastian F. Sanchez, Jose R. Sanchez-Gallego, Basilio Xavier Santiago, Ricardo Schiavon, Jaderson S. Schimoia, Eddie Schlafly, David J. Schlegel, Donald P. Schneider, Ralph Schoenrich, Mathias Schultheis, Axel Schwope, Hee-Jong Seo, Aldo Serenelli, Branimir Sesar, Zhengyi Shao, Matthew Shetrone, Michael Shull, Victor Silva Aguirre, M. F. Skrutskie, Anže Slosar, Michael Smith, Verne V. Smith, Jennifer Sobeck, Garrett Somers, Diogo Souto, David V. Stark, Keivan G. Stassun, Matthias Steinmetz, Dennis Stello, Thaisa Storchi Bergmann, Michael A. Strauss, Alina Streblyanska, Guy S. Stringfellow, Genaro Suarez, Jing Sun, Manuchehr Taghizadeh-Popp, Baitian Tang, Charling Tao, Jamie Tayar, Mita Tembe, Daniel Thomas, Jeremy Tinker, Rita Tojeiro, Christy Tremonti, Nicholas Troup, Jonathan R. Trump, Eduardo Unda-Sanzana, O. Valenzuela, Remco van den Bosch, Mariana Vargas-Magana, Jose Alberto Vazquez, Sandro Villanova, M. Vivek, Nicole Vogt, David Wake, Rene Walterbos, Yuting Wang, Enci Wang, Benjamin Alan Weaver, Anne-Marie Weijmans, David H. Weinberg, Kyle B. Westfall, David G. Whelan, Eric Wilcots, Vivienne Wild, Rob A. Williams, John Wilson, W. M. Wood-Vasey, Dominika Wylezalek, Ting Xiao, Renbin Yan, Meng Yang, Jason E. Ybarra, Christophe Yeche, Fang-Ting Yuan, Nadia Zakamska, Olga Zamora, Gail Zasowski, Kai Zhang, Cheng Zhao, Gong-Bo Zhao, Zheng Zheng, Zheng Zheng, Zhi-Min Zhou, Guangtun Zhu, Joel C. Zinn, Hu Zou

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in July 2014. It pursues three core programs: APOGEE-2, MaNGA, and eBOSS. In addition, eBOSS contains two major subprograms: TDSS and SPIDERS. Read More

Theoretical models and spectroscopic observations of newborn stars suggest that protoplantary disks have an inner "wall" at a distance set by the disk interaction with the star. Around T Tauri stars, the size of this disk hole is expected to be on a 0.1-AU scale that is unresolved by current adaptive optics imaging, though some model-dependent constraints have been obtained by near-infrared interferometry. Read More

2016Jan
Affiliations: 1Western Washington Univ, 2Columbia Univ, 3Univ. of North Carolina-Chapel Hill, 4Columbia Univ, 5Max Planck Institut for Radioastronomy, 6Spitzer Science Center, 7California Institute of Technology, 8Max Planck Institute for Astronomy, 9Spitzer Science Center

Stellar rotation periods measured in open clusters have proved to be extremely useful for studying stars' angular momentum content and rotationally driven magnetic activity, which are both age- and mass-dependent processes. While period measurements have been obtained for hundreds of solar-mass members of the Pleiades, period measurements exist for only a few low-mass ($<$0.5 M$_{\odot}$) members of this key laboratory for stellar evolution theory. Read More

We provide CoRoT and Spitzer light curves, as well as broad-band multi-wavelength photometry and high resolution, multi- and single-epoch spectroscopy for 17 classical T Tauris in NGC 2264 whose CoRoT light curves (LCs) exemplify the "stochastic" LC class as defined in Cody et al. (2014). The most probable physical mechanism to explain the optical variability in this LC class is time-dependent mass accretion onto the stellar photosphere, producing transient hot spots. Read More

In its three years of operation, the Sloan Digital Sky Survey (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE-1) observed $>$14,000 stars with enough epochs over a sufficient temporal baseline for the fitting of Keplerian orbits. We present the custom orbit-fitting pipeline used to create this catalog, which includes novel quality metrics that account for the phase and velocity coverage of a fitted Keplerian orbit. With a typical RV precision of $\sim100-200$ m s$^{-1}$, APOGEE can probe systems with small separation companions down to a few Jupiter masses. Read More

2015Nov
Affiliations: 1Department of Astronomy, University of Florida, 2Department of Astronomy, University of Florida, 3Western Washington University, 4University of Oxford, 5Yale, 6Department of Astronomy, University of Florida, 7Leiden Observatory, 8Steward Observatory, 9ETH Zurich, 10University of Michigan, 11Vanderbilt University, 12University of Virginia, 13Wesleyan University, 14University of Virginia, 15University of Virginia, 16University of Virginia, 17Apache Point Observatory and New Mexico State University

We present the results of the SDSS APOGEE INfrared Spectroscopy of Young Nebulous Clusters program (IN-SYNC) survey of the Orion A molecular cloud. This survey obtained high resolution near infrared (NIR) spectroscopy of about 2700 young pre-main sequence stars throughout the region, acquired across five distinct fields spanning 6deg field of view (FOV). With these spectra, we have measured accurate stellar parameters (T_eff, log g, v sin i) and extinctions, and placed the sources in the Hertzsprung-Russel Diagram (HRD). Read More

Empirical calibrations of the stellar age-rotation-activity relation (ARAR) rely on observations of the co-eval populations of stars in open clusters. We used the Chandra X-ray Observatory to study M37, a 500-Myr-old open cluster that has been extensively surveyed for rotation periods ($P_{\rm rot}$). M37 was observed almost continuously for five days, for a total of 440. Read More

Most field stars will have encountered the highest stellar density and hence the largest number of interactions in their birth environment. Yet the stellar dynamics during this crucial phase are poorly understood. Here we analyze the radial velocities measured for 152 out of 380 observed stars in the 2-6 Myr old star cluster IC 348 as part of the SDSS-III APOGEE. Read More

Evolutionary models of pre-main sequence stars remain largely uncalibrated, especially for masses below that of the Sun, making each new dynamical mass and radius measurement a valuable test of theoretical models. Stellar mass dependent features of star formation (such as disk evolution, planet formation, and even the IMF) are fundamentally tied to these models, which implies a systematic uncertainty that can only be improved with precise measurements of calibrator stars. We present the discovery that UScoCTIO 5, a known spectroscopic binary (P = 34 days, Mtot sin(i) = 0. Read More

We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical {\em CoRoT} light curves exhibiting short-duration, shallow, periodic flux dips. All of these stars have infrared (IR) excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHM generally less than one day, depths almost always less than 15%, and periods (3Read More

2015Jan
Authors: Shadab Alam1, Franco D. Albareti2, Carlos Allende Prieto3, F. Anders4, Scott F. Anderson5, Brett H. Andrews6, Eric Armengaud7, Éric Aubourg8, Stephen Bailey9, Julian E. Bautista10, Rachael L. Beaton11, Timothy C. Beers12, Chad F. Bender13, Andreas A. Berlind14, Florian Beutler15, Vaishali Bhardwaj16, Jonathan C. Bird17, Dmitry Bizyaev18, Cullen H. Blake19, Michael R. Blanton20, Michael Blomqvist21, John J. Bochanski22, Adam S. Bolton23, Jo Bovy24, A. Shelden Bradley25, W. N. Brandt26, D. E. Brauer27, J. Brinkmann28, Peter J. Brown29, Joel R. Brownstein30, Angela Burden31, Etienne Burtin32, Nicolás G. Busca33, Zheng Cai34, Diego Capozzi35, Aurelio Carnero Rosell36, Ricardo Carrera37, Yen-Chi Chen38, Cristina Chiappini39, S. Drew Chojnowski40, Chia-Hsun Chuang41, Nicolas Clerc42, Johan Comparat43, Kevin Covey44, Rupert A. C. Croft45, Antonio J. Cuesta46, Katia Cunha47, Luiz N. da Costa48, Nicola Da Rio49, James R. A. Davenport50, Kyle S. Dawson51, Nathan De Lee52, Timothée Delubac53, Rohit Deshpande54, Letícia Dutra-Ferreira55, Tom Dwelly56, Anne Ealet57, Garrett L. Ebelke58, Edward M. Edmondson59, Daniel J. Eisenstein60, Stephanie Escoffier61, Massimiliano Esposito62, Xiaohui Fan63, Emma Fernández-Alvar64, Diane Feuillet65, Nurten Filiz Ak66, Hayley Finley67, Alexis Finoguenov68, Kevin Flaherty69, Scott W. Fleming70, Andreu Font-Ribera71, Jonathan Foster72, Peter M. Frinchaboy73, J. G. Galbraith-Frew74, D. A. García-Hernández75, Ana E. García Pérez76, Patrick Gaulme77, Jian Ge78, R. Génova-Santos79, Luan Ghezzi80, Bruce A. Gillespie81, Léo Girardi82, Daniel Goddard83, Satya Gontcho A Gontcho84, Jonay I. González Hernández85, Eva K. Grebel86, Jan Niklas Grieb87, Nolan Grieves88, James E. Gunn89, Hong Guo90, Paul Harding91, Sten Hasselquist92, Suzanne L. Hawley93, Michael Hayden94, Fred R. Hearty95, Shirley Ho96, David W. Hogg97, Kelly Holley-Bockelmann98, Jon A. Holtzman99, Klaus Honscheid100, Joseph Huehnerhoff101, Linhua Jiang102, Jennifer A. Johnson103, Karen Kinemuchi104, David Kirkby105, Francisco Kitaura106, Mark A. Klaene107, Jean-Paul Kneib108, Xavier P. Koenig109, Charles R. Lam110, Ting-Wen Lan111, Dustin Lang112, Pierre Laurent113, Jean-Marc Le Goff114, Alexie Leauthaud115, Khee-Gan Lee116, Young Sun Lee117, Timothy C. Licquia118, Jian Liu119, Daniel C. Long120, Martín López-Corredoira121, Diego Lorenzo-Oliveira122, Sara Lucatello123, Britt Lundgren124, Robert H. Lupton125, Claude E. Mack III126, Suvrath Mahadevan127, Marcio A. G. Maia128, Steven R. Majewski129, Elena Malanushenko130, Viktor Malanushenko131, A. Manchado132, Marc Manera133, Qingqing Mao134, Claudia Maraston135, Robert C. Marchwinski136, Daniel Margala137, Sarah L. Martell138, Marie Martig139, Karen L. Masters140, Cameron K. McBride141, Peregrine M. McGehee142, Ian D. McGreer143, Richard G. McMahon144, Brice Ménard145, Marie-Luise Menzel146, Andrea Merloni147, Szabolcs Mészáros148, Adam A. Miller149, Jordi Miralda-Escudé150, Hironao Miyatake151, Antonio D. Montero-Dorta152, Surhud More153, Xan Morice-Atkinson154, Heather L. Morrison155, Demitri Muna156, Adam D. Myers157, Jeffrey A. Newman158, Mark Neyrinck159, Duy Cuong Nguyen160, Robert C. Nichol161, David L. Nidever162, Pasquier Noterdaeme163, Sebastián E. Nuza164, Julia E. O'Connell165, Robert W. O'Connell166, Ross O'Connell167, Ricardo L. C. Ogando168, Matthew D. Olmstead169, Audrey E. Oravetz170, Daniel J. Oravetz171, Keisuke Osumi172, Russell Owen173, Deborah L. Padgett174, Nikhil Padmanabhan175, Martin Paegert176, Nathalie Palanque-Delabrouille177, Kaike Pan178, John K. Parejko179, Changbom Park180, Isabelle Pâris181, Petchara Pattarakijwanich182, M. Pellejero-Ibanez183, Joshua Pepper184, Will J. Percival185, Ismael Pérez-Fournon186, Ignasi Pérez-Ràfols187, Patrick Petitjean188, Matthew M. Pieri189, Marc H. Pinsonneault190, Gustavo F. Porto de Mello191, Francisco Prada192, Abhishek Prakash193, Adrian M. Price-Whelan194, M. Jordan Raddick195, Mubdi Rahman196, Beth A. Reid197, James Rich198, Hans-Walter Rix199, Annie C. Robin200, Constance M. Rockosi201, Thaíse S. Rodrigues202, Sergio Rodríguez-Rottes203, Natalie A. Roe204, Ashley J. Ross205, Nicholas P. Ross206, Graziano Rossi207, John J. Ruan208, J. A. Rubiño-Martín209, Eli S. Rykoff210, Salvador Salazar-Albornoz211, Mara Salvato212, Lado Samushia213, Ariel G. Sánchez214, Basílio Santiago215, Conor Sayres216, Ricardo P. Schiavon217, David J. Schlegel218, Sarah J. Schmidt219, Donald P. Schneider220, Mathias Schultheis221, Axel D. Schwope222, C. G. Scóccola223, Kris Sellgren224, Hee-Jong Seo225, Neville Shane226, Yue Shen227, Matthew Shetrone228, Yiping Shu229, Thirupathi Sivarani230, M. F. Skrutskie231, Anže Slosar232, Verne V. Smith233, Flávia Sobreira234, Keivan G. Stassun235, Matthias Steinmetz236, Michael A. Strauss237, Alina Streblyanska238, Molly E. C. Swanson239, Jonathan C. Tan240, Jamie Tayar241, Ryan C. Terrien242, Aniruddha R. Thakar243, Daniel Thomas244, Benjamin A. Thompson245, Jeremy L. Tinker246, Rita Tojeiro247, Nicholas W. Troup248, Mariana Vargas-Magaña249, Jose A. Vazquez250, Licia Verde251, Matteo Viel252, Nicole P. Vogt253, David A. Wake254, Ji Wang255, Benjamin A. Weaver256, David H. Weinberg257, Benjamin J. Weiner258, Martin White259, John C. Wilson260, John P. Wisniewski261, W. M. Wood-Vasey262, Christophe Yèche263, Donald G. York264, Nadia L. Zakamska265, O. Zamora266, Gail Zasowski267, Idit Zehavi268, Gong-Bo Zhao269, Zheng Zheng270, Xu Zhou271, Zhimin Zhou272, Guangtun Zhu273, Hu Zou274
Affiliations: 1Bruce and Astrid McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA, 2Instituto de Física Teórica, 3Instituto de Astrofísica de Canarias, 4Leibniz-Institut für Astrophysik Potsdam, 5Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA, 6Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, 7CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette, France, 8APC, University of Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cité, F-75205 Paris, France, 9Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA, 10APC, University of Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cité, F-75205 Paris, France, 11Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 12Department of Physics and JINA Center for the Evolution of the Elements, University of Notre Dame, Notre Dame, IN 46556 USA, 13Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, 14Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235, USA, 15Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA, 16Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA, 17Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235, USA, 18Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 19University of Pennsylvania, Department of Physics and Astronomy, 219 S. 33rd St., Philadelphia, PA 19104, USA, 20Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003, USA, 21Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA, 22Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA, 23Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA, 24Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540, USA, 25Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 26Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, 27Leibniz-Institut für Astrophysik Potsdam, 28Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 29George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A. and M. University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843, USA, 30Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA, 31Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 32CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette, France, 33Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil, 34Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA, 35Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 36Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil, 37Instituto de Astrofísica de Canarias, 38Department of Statistics, Bruce and Astrid McWilliams Center for Cosmology, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA, 39Leibniz-Institut für Astrophysik Potsdam, 40Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003, USA, 41Instituto de Física Teórica, 42Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstr. D-85741 Garching, Germany, 43Instituto de Física Teórica, 44Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff AZ 86001, 45Bruce and Astrid McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA, 46Institut de Ciències del Cosmos, Universitat de Barcelona/IEEC, Barcelona E-08028, Spain, 47Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil, 48Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil, 49Department of Astronomy, University of Florida, Bryant Space Science Center, Gainesville, FL 32611-2055, USA, 50Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA, 51Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA, 52Department of Physics and Geology, Northern Kentucky University, Highland Heights, KY 41099, USA, 53Laboratoire d'Astrophysique, École Polytechnique Fédérale de Lausanne, 54Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, 55Universidade Federal do Rio de Janeiro, Observatório do Valongo, Ladeira do Pedro Antônio 43, 20080-090 Rio de Janeiro, Brazil, 56Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstr. D-85741 Garching, Germany, 57Centre de Physique des Particules de Marseille, Aix-Marseille Université, CNRS/IN2P3, E-13288 Marseille, France, 58Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 59Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 60Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA, 61Centre de Physique des Particules de Marseille, Aix-Marseille Université, CNRS/IN2P3, E-13288 Marseille, France, 62Instituto de Astrofísica de Canarias, 63Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA, 64Instituto de Astrofísica de Canarias, 65Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003, USA, 66Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, 67Institut d'Astrophysique de Paris, UPMC-CNRS, UMR7095, 98 bis Boulevard Arago, F-75014, Paris, France, 68Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2, Helsinki FI-00140, Finland, 69Department of Astronomy, Van Vleck Observatory, Wesleyan University, Middletown, CT 06459, 70Space Telescope Science Institute, 3700 San Martin Dr, Baltimore, MD 21218, USA, 71Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA, 72Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT, 06520, USA, 73Department of Physics and Astronomy, Texas Christian University, 2800 South University Drive, Fort Worth, TX 76129, USA, 74Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA, 75Instituto de Astrofísica de Canarias, 76Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 77Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 78Department of Astronomy, University of Florida, Bryant Space Science Center, Gainesville, FL 32611-2055, USA, 79Instituto de Astrofísica de Canarias, 80Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil, 81Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 82INAF, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy, 83Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 84Institut de Ciències del Cosmos, Universitat de Barcelona/IEEC, Barcelona E-08028, Spain, 85Instituto de Astrofísica de Canarias, 86Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12--14, D-69120 Heidelberg, Germany, 87Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstr. D-85741 Garching, Germany, 88Department of Astronomy, University of Florida, Bryant Space Science Center, Gainesville, FL 32611-2055, USA, 89Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA, 90Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA, 91Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106, USA, 92Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003, USA, 93Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA, 94Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003, USA, 95Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, 96Bruce and Astrid McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA, 97Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003, USA, 98Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235, USA, 99Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003, USA, 100Department of Physics, Ohio State University, Columbus, OH 43210, USA, 101Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 102Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China, 103Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, 104Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 105Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA, 106Leibniz-Institut für Astrophysik Potsdam, 107Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 108Laboratoire d'Astrophysique, École Polytechnique Fédérale de Lausanne, 109Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101, USA, 110Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 111Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 112Bruce and Astrid McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA, 113CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette, France, 114CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette, France, 115Kavli Institute for the Physics and Mathematics of the Universe, 116Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany, 117Department of Astronomy and Space Science Chungnam National University Daejeon 305-764, Repulic of Korea, 118PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260, USA, 119Department of Astronomy, University of Florida, Bryant Space Science Center, Gainesville, FL 32611-2055, USA, 120Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 121Instituto de Astrofísica de Canarias, 122Universidade Federal do Rio de Janeiro, Observatório do Valongo, Ladeira do Pedro Antônio 43, 20080-090 Rio de Janeiro, Brazil, 123INAF, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy, 124Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison WI 53703, USA, 125Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA, 126Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235, USA, 127Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, 128Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil, 129Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 130Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 131Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 132Instituto de Astrofísica de Canarias, 133Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 134Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235, USA, 135Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 136Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, 137Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA, 138School of Physics, University of New South Wales, Sydney, NSW 2052, Australia, 139Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany, 140Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 141Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA, 142IPAC, MS 220-6, California Institute of Technology, Pasadena, CA 91125, USA, 143Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA, 144Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK, 145Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 146Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstr. D-85741 Garching, Germany, 147Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstr. D-85741 Garching, Germany, 148ELTE Gothard Astrophysical Observatory, H-9704 Szombathely, Szent Imre herceg st. 112, Hungary, 149Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA, 150Institució Catalana de Recerca i Estudis Avançats, Barcelona E-08010, Spain, 151Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA, 152Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA, 153Kavli Institute for the Physics and Mathematics of the Universe, 154Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 155Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106, USA, 156Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, 157Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA, 158PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260, USA, 159Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 160Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, ON, M5S 3H4, Canada, 161Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 162Dept. of Astronomy, University of Michigan, Ann Arbor, MI, 48104, USA, 163Institut d'Astrophysique de Paris, UPMC-CNRS, UMR7095, 98 bis Boulevard Arago, F-75014, Paris, France, 164Leibniz-Institut für Astrophysik Potsdam, 165Department of Physics and Astronomy, Texas Christian University, 2800 South University Drive, Fort Worth, TX 76129, USA, 166Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 167Bruce and Astrid McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA, 168Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil, 169Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA, 170Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 171Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 172Bruce and Astrid McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA, 173Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA, 174NASA/GSFC, Code 665, Greenbelt, MC 20770, USA, 175Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT, 06520, USA, 176Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235, USA, 177CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette, France, 178Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA, 179Department of Physics, Yale University, 260 Whitney Ave, New Haven, CT, 06520, USA, 180School of Physics, Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 130-722, Republic of Korea, 181INAF, Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34131 Trieste, Italy, 182Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA, 183Instituto de Astrofísica de Canarias, 184Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA 18015, USA, 185Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 186Instituto de Astrofísica de Canarias, 187Institut de Ciències del Cosmos, Universitat de Barcelona/IEEC, Barcelona E-08028, Spain, 188Institut d'Astrophysique de Paris, UPMC-CNRS, UMR7095, 98 bis Boulevard Arago, F-75014, Paris, France, 189A*MIDEX, Aix Marseille Université, CNRS, LAM, 190Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, 191Universidade Federal do Rio de Janeiro, Observatório do Valongo, Ladeira do Pedro Antônio 43, 20080-090 Rio de Janeiro, Brazil, 192Instituto de Física Teórica, 193PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260, USA, 194Department of Astronomy, Columbia University, New York, NY 10027, USA, 195Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 196Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 197Department of Physics, University of California, Berkeley, CA 94720, USA, 198CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette, France, 199Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany, 200Université de Franche-Comté, Institut Utinam, UMR CNRS 6213, OSU Theta, Besançon, F-25010, France, 201Department of Astronomy and Astrophysics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA, 202INAF, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy, 203Instituto de Física Teórica, 204Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA, 205Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 206Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA, 207Department of Astronomy and Space Science, Sejong University, Seoul, 143-747, Korea, 208Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA, 209Instituto de Astrofísica de Canarias, 210SLAC National Accelerator Laboratory, Menlo Park, CA 94025, 211Universitäts-Sternwarte München, Scheinerstrasse 1, D-81679 Munich, Germany, 212Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstr. D-85741 Garching, Germany, 213Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506, USA, 214Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstr. D-85741 Garching, Germany, 215Instituto de Física, UFRGS, Caixa Postal 15051, Porto Alegre, RS - 91501-970, Brazil, 216Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA, 217Gemini Observatory, 670 N. A'Ohoku Place, Hilo, HI 96720, USA, 218Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA, 219Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, 220Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, 221Université de Nice Sophia-Antipolis, CNRS, Observatoire de Côte d'Azur, Laboratoire Lagrange, BP 4229, F-06304 Nice Cedex 4, France, 222Leibniz-Institut für Astrophysik Potsdam, 223Instituto de Astrofísica de Canarias, 224Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, 225Department of Physics and Astronomy, Ohio University, 251B Clippinger Labs, Athens, OH 45701, USA, 226Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 227Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA, 228University of Texas at Austin, Hobby-Eberly Telescope, 32 Fowlkes Rd, McDonald Observatory, TX 79734-3005, USA, 229Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA, 230Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034, India, 231Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 232Brookhaven National Laboratory, Bldg 510, Upton, NY 11973, USA, 233National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ, 85719, USA, 234Laboratório Interinstitucional de e-Astronomia, - LIneA, Rua Gal.José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil, 235Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235, USA, 236Leibniz-Institut für Astrophysik Potsdam, 237Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA, 238Instituto de Astrofísica de Canarias, 239Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA, 240Department of Astronomy, University of Florida, Bryant Space Science Center, Gainesville, FL 32611-2055, USA, 241Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, 242Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, 243Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 244Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK, 245Department of Physics and Astronomy, Texas Christian University, 2800 South University Drive, Fort Worth, TX 76129, USA, 246Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003, USA, 247School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, KY16 9SS, UK, 248Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 249Bruce and Astrid McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA, 250Brookhaven National Laboratory, Bldg 510, Upton, NY 11973, USA, 251Institució Catalana de Recerca i Estudis Avançats, Barcelona E-08010, Spain, 252INAF, Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34131 Trieste, Italy, 253Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003, USA, 254Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison WI 53703, USA, 255Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101, USA, 256Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003, USA, 257Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA, 258Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA, 259Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA, 260Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA, 261H.L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA, 262PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260, USA, 263CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette, France, 264Department of Astronomy and Astrophysics and the Enrico Fermi Institute, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA, 265Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 266Instituto de Astrofísica de Canarias, 267Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 268Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106, USA, 269National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012, China, 270Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA, 271Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012, China, 272Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012, China, 273Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA, 274Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012, China

The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Read More

The remarkable scientific return and legacy of LSST, in the era that it will define, will not only be realized in the breakthrough science that will be achieved with catalog data. This Big Data survey will shape the way the entire astronomical community advances -- or fails to embrace -- new ways of approaching astronomical research and data. In this white paper, we address the NRC template questions 4,5,6,8 and 9, with a focus on the unique challenges for smaller, and often under-resourced, institutions, including institutions dedicated to underserved minority populations, in the efficient and effective use of LSST data products to maximize LSST's scientific return. Read More

Over two years 8,859 high-resolution H-band spectra of 3,493 young (1 - 10 Myr) stars were gathered by the multi-object spectrograph of the APOGEE project as part of the IN-SYNC ancillary program of that SDSS-III survey. Here we present the forward modeling approach used to derive effective temperatures, surface gravities, radial velocities, rotational velocities, and H-band veiling from these near-infrared spectra. We discuss in detail the statistical and systematic uncertainties in these stellar parameters. Read More

We present H- and K-band spectra for late-type Kepler Objects of Interest (the "Cool KOIs"): low-mass stars with transiting-planet candidates discovered by NASA's Kepler Mission that are listed on the NASA Exoplanet Archive. We acquired spectra of 103 Cool KOIs and used the indices and calibrations of Rojas-Ayala et al. to determine their spectral types, stellar effective temperatures and metallicities, significantly augmenting previously published values. Read More

We present the fiducial main sequence stellar locus traced by 10 photometric colors observed by SDSS, 2MASS, and WISE. Median colors are determined using 1,052,793 stars with r-band extinction less than 0.125. Read More

Based on more than four weeks of continuous high cadence photometric monitoring of several hundred members of the young cluster NGC 2264 with two space telescopes, NASA's Spitzer and the CNES CoRoT (Convection, Rotation, and planetary Transits), we provide high quality, multi-wavelength light curves for young stellar objects (YSOs) whose optical variability is dominated by short duration flux bursts, which we infer are due to enhanced mass accretion rates. These light curves show many brief -- several hour to one day -- brightenings at optical and near-infrared (IR) wavelengths with amplitudes generally in the range 5-50% of the quiescent value. Typically, a dozen or more of these bursts occur in a thirty day period. Read More

Many photometric time-domain surveys are driven by specific goals, such as searches for supernovae or transiting exoplanets, which set the cadence with which fields are re-imaged. In the case of the Palomar Transient Factory (PTF), several sub-surveys are conducted in parallel, leading to non-uniform sampling over its $\sim$$20,000 \mathrm{deg}^2$ footprint. While the median $7. Read More

We present metallicities, radial velocities and near-infrared spectral types for 447 M dwarfs determined from moderate resolution (R~2000) near-infrared (NIR) spectra obtained with IRTF/SpeX. These M dwarfs are targets of the MEarth Survey, a transiting planet survey searching for super Earths around mid-to-late M dwarfs within 33pc. We present NIR spectral types and new IRTF spectral templates in the Z, J, H and K-bands, created using M dwarfs with near-solar metallicities. Read More

With the loss of two reaction wheels, the period of Kepler's ultra-high precision photometric performance is at an end. Yet Kepler retains unique capabilities impossible to replicate from the ground or with existing or future space missions. This White Paper calls for the use of Kepler to conduct a survey in the ecliptic plane to search for planet transits around stars at high galactic latitudes and to study star forming regions to investigate physics of very young stars not studied by Kepler in its prime mission. Read More

2013Sep
Affiliations: 1Cornell University, 2Cornell University, 3University of Rochester, 4Institute for Advanced Study, 5Lowell Observatory, 6Lowell Observatory, 7Princeton University, 8Instituto Nacional de Astrofísica, Óptica y Electrónica, 9Instituto Nacional de Astrofísica, Óptica y Electrónica, 10Instituto Nacional de Astrofísica, Óptica y Electrónica

This white paper discusses a repurposed mission for the Kepler spacecraft that focusses on solving outstanding problems in planet formation and evolution by targeting the study of the hot Jupiter population of young stars. This mission can solve the question of the mode of migration of hot Jupiters, address the problem of whether Jupiters form by hot-start (gravitational instability) or cold-start (core accretion) mechanisms, and provide a wealth of data on the early stages of planetary system evolution during the active phases of stars which impact planetary habitability. In one year of observations of three weeks dwell time per field, Kepler would increase by more than an order of magnitude the number of known hot Jupiters, which can be followed up with fast cadence observations to to search for transit timing variations and to perform asteroseismological characterization of the host stars. Read More

Even with the diminished precision possible with only two reaction wheels, the Kepler spacecraft can obtain mmag level, time-resolved photometry of tens of thousands of sources. The presence of such a rich, large data set could be transformative for stellar astronomy. In this white paper, we discuss how rotation periods for a large ensemble of single and binary main- sequence dwarfs can yield a quantitative understanding of the evolution of stellar spin-down over time. Read More

We investigate the shape of the extinction law in two 1-degree square fields of the Perseus Molecular Cloud complex. We combine deep red-optical (r, i, and z-band) observations obtained using Megacam on the MMT with UKIDSS near-infrared (J, H, and K-band) data to measure the colours of background stars. We develop a new hierarchical Bayesian statistical model, including measurement error, intrinsic colour variation, spectral type, and dust reddening, to simultaneously infer parameters for individual stars and characteristics of the population. Read More

Recent studies have identified several young stellar objects (YSOs) which exhibit significant mid-infrared (mid-IR) variability. A wide range of physical mechanisms may be responsible for these variations, including changes in a YSO's accretion rate or in the extinction or emission from the inner disk. We have obtained and analyzed multi-epoch near-infrared (NIR) spectra for five actively accreting YSOs in the $\rho$ Oph star-forming region along with contemporaneous mid-IR light curves obtained as part of the YSOVAR Spitzer/IRAC survey. Read More

We report extensive new photometry and spectroscopy of the highly variable young stellar object PTF 10nvg including optical and near-infrared time series data as well as mid-infrared and millimeter data. Following the previously reported 2010 rise, during 2011 and 2012 the source underwent additional episodes of brightening and dimming events including prolonged faint states. The observed high-amplitude variations are largely consistent with extinction changes having a 220 day quasi-periodic signal. Read More

We present the characterization of the star KOI 961, an M dwarf with transit signals indicative of three short-period exoplanets, originally discovered by the Kepler Mission. We proceed by comparing KOI 961 to Barnard's Star, a nearby, well-characterized mid-M dwarf. By comparing colors, optical and near-infrared spectra, we find remarkable agreement between the two, implying similar effective temperatures and metallicities. Read More

We present K band spectra for 133 nearby (d < 33 parsecs) M dwarfs, including 18 M dwarfs with reliable metallicity estimates (as inferred from an FGK type companion), 11 M dwarf planet hosts, more than 2/3 of the M dwarfs in the Northern 8 pc sample, and several M dwarfs from the LSPM catalog. From these spectra, we measure equivalent widths of the Ca and Na lines, and a spectral index quantifying the absorption due to H2O opacity (the H2O-K2 index). Using empirical spectral types standards and synthetic models, we calibrate the H2O-K2 index as an indicator of an M dwarf's spectral type and effective temperature. Read More

We report the confirmation and characterization of a transiting gas giant planet orbiting the M dwarf KOI-254 every 2.455239 days, which was originally discovered by the Kepler mission. We use radial velocity measurements, adaptive optics imaging and near infrared spectroscopy to confirm the planetary nature of the transit events. Read More

We report stellar parameters for late-K and M-type planet-candidate host stars announced by the Kepler Mission. We obtained medium-resolution, K-band spectra of 84 cool (Teff < 4400 K) Kepler Objects of Interest (KOIs) from Borucki et al. We identified one object as a giant (KOI 977); for the remaining dwarfs, we measured effective temperatures (Teff) and metallicities ([M/H]) using the K-band spectral indices of Rojas-Ayala et al. Read More

The initial mass function (IMF) succinctly characterizes a stellar population, provides a statistical measure of the end result of the star-formation process, and informs our under- standing of the structure and dynamical evolution of stellar clusters, the Milky Way, and other galaxies. Detecting variations in the form of the IMF could provide powerful insights into the processes that govern the formation and evolution of stars, clusters, and galaxies. In this contribution, we review measurements of the IMF in resolved stellar populations, and critically assess the evidence for systematic IMF variations. Read More

2011Jul
Affiliations: 1Columbia, 2Cornell, 3Columbia, 4Toronto, 5IfA, 6Cornell, 7Berkeley, 8Berkeley, 9Caltech, 10Caltech, 11LBNL, 12Caltech, 13Berkeley, 14Caltech

Stellar rotation periods measured from single-age populations are critical for investigating how stellar angular momentum content evolves over time, how that evolution depends on mass, and how rotation influences the stellar dynamo and the magnetically heated chromosphere and corona. We report rotation periods for 40 late-K to mid-M stars members of the nearby, rich, intermediate-age (~600 Myr) open cluster Praesepe. These rotation periods were derived from ~200 observations taken by the Palomar Transient Factory of four cluster fields from 2010 February to May. Read More

Theoretical work suggests that a young star's angular momentum and rotation rate may be strongly influenced by magnetic interactions with its circumstellar disk. A generic prediction of these 'disk-locking' (DL) theories is that a disk-locked star will be forced to co-rotate with the Keplerian angular velocity of the inner edge of the disk. These theories have also been interpreted to suggest a correlation between young stars' rotation periods and the structural properties of their disks, such that slowly rotating stars possess close-in disks that enforce the star's slow rotation, whereas rapidly rotating stars possess anemic or evacuated inner disks that are unable to brake the stars and they spin up as they contract. Read More

Precise near-infrared radial velocimetry enables efficient detection and transit verification of low-mass extrasolar planets orbiting M dwarf hosts, which are faint for visible-wavelength radial velocity surveys. The TripleSpec Exoplanet Discovery Instrument, or TEDI, is the combination of a variable-delay Michelson interferometer and a medium-resolution (R=2700) near-infrared spectrograph on the Palomar 200" Hale Telescope. We used TEDI to monitor GJ 699, a nearby mid-M dwarf, over 11 nights spread across 3 months. Read More

We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release of the Sloan Digital Sky Survey (SDSS). For each spectrum, we provide measurements of the spectral type, a number of molecular bandheads, and the H-alpha, H-beta, H-gamma, H-delta and Ca II K emission lines. In addition, we calculate the metallicity-sensitive parameter zeta and identify a relationship between zeta and the g-r and r-z colors of M dwarfs. Read More

Variability is a defining characteristic of young stellar systems, and optical variability has been heavily studied to select and characterize the photospheric properties of young stars. In recent years, multi-epoch observations sampling a wider range of wavelengths and time-scales have revealed a wealth of time-variable phenomena at work during the star formation process. This splinter session was convened to summarize recent progress in providing improved coverage and understanding of time-variable processes in young stars and circumstellar disks. Read More

We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release (DR7) of the Sloan Digital Sky Survey (SDSS). For each spectrum, we provide measurements of the spectral type, a number of molecular bandheads, and the H-alpha, H-beta, H-gamma, H-delta and Ca II K emission lines. In addition, we calculate the metallicity-sensitive parameter zeta and 3D space motions for most of the stars in the sample. Read More

The difference in stellar structure above and below spectral type ~M4 is expected to be a very important one, connected directly or indirectly to a variety of observational phenomena in cool stars---such as rotation, activity, magnetic field generation and topology, timescales for evolution of these, and even the basic mass-radius relationship. In this Cool Stars XVI Splinter Session, we aimed to use the M4 transition as an opportunity for discussion about the interiors of low-mass stars and the mechanisms which determine their fundamental properties. By the conclusion of the session, several key points were elucidated. Read More

Few topics in astronomy initiate such vigorous discussion as whether or not the initial mass function (IMF) of stars is universal, or instead sensitive to the initial conditions of star formation. The distinction is of critical importance: the IMF influences most of the observable properties of stellar populations and galaxies, and detecting variations in the IMF could provide deep insights into the process by which stars form. In this contribution, we take a critical look at the case for IMF variations, with a view towards whether other explanations are sufficient given the evidence. Read More

Over the past 40 years, observational surveys have established the existence of a tight relationship between a star's age, rotation period, and magnetic activity. This age-rotation-activity relation documents the interplay between a star's magnetic dynamo and angular momentum evolution, and provides a valuable age estimator for isolated field stars. While the age-rotation-activity relation has been studied extensively in clusters younger than 500 Myr, empirically measured rotation periods are scarce for older ages. Read More

During a synoptic survey of the North American Nebula region, the Palomar Transient Factory (PTF) detected an optical outburst (dubbed PTF10nvg) associated with the previously unstudied flat or rising spectrum infrared source IRAS 20496+4354. The PTF R-band light curve reveals that PTF10nvg brightened by more than 5 mag during the current outburst, rising to a peak magnitude of R~13.5 in 2010 Sep. Read More

2010Nov
Affiliations: 1UC Berkeley, 2CIT, 3Cornell, 4UC Berkeley, 5UC Berkeley, 6UC Berkeley, 7Cornell, 8Cornell, 9UC Berkeley, 10UC Berkeley, 11CIT, 12UC Berkeley, 13UToronto, 14CIT, 15COO/CIT, 16COO/CIT, 17COO/CIT, 18COO/CIT, 19CIT, 20LBNL, 21LBNL, 22COO/CIT, 23COO/CIT, 24COO/CIT, 25COO/CIT, 26COO/CIT, 27COO/CIT, 28CIT, 29UC Berkeley

We present pre- and post-outburst observations of the new FU Orionis-like young stellar object PTF 10qpf (also known as LkHa 188-G4 and HBC 722). Prior to this outburst, LkHa 188-G4 was classified as a classical T Tauri star on the basis of its optical emission-line spectrum superposed on a K8-type photosphere, and its photometric variability. The mid-infrared spectral index of LkHa 188-G4 indicates a Class II-type object. Read More

Transit light curves for stellar continua have only one minimum and a "U" shape. By contrast, transit curves for optically thin chromospheric emission lines can have a "W" shape because of stellar limb-brightening. We calculate light curves for an optically thin shell of emission and fit these models to time-resolved observations of Si IV absorption by the planet HD209458b. Read More