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Ross 19B: An Extremely Cold Companion Discovered via the Backyard Worlds: Planet 9 Citizen Science Project

Schneider, Adam C. and Meisner, Aaron M. and Gagné, Jonathan and Faherty, Jacqueline K. and Marocco, Federico and Burgasser, Adam J. and Kirkpatrick, J. Davy and Kuchner, Marc J. and Gramaize, Léopold and Rothermich, Austin and Brooks, Hunter and Vrba, Frederick J. and Bardalez Gagliuffi, Daniella and Caselden, Dan and Cushing, Michael C. and Gelino, Christopher R. and Line, Michael R. and Casewell, Sarah L. and Debes, John H. and Aganze, Christian and Ayala, Andrew and Gerasimov, Roman and Gonzales, Eileen C. and Hsu, Chih-Chun and Kiman, Rocio and Popinchalk, Mark and Theissen, Christopher (2021) Ross 19B: An Extremely Cold Companion Discovered via the Backyard Worlds: Planet 9 Citizen Science Project. Astrophysical Journal, 921 (2). Art. No. 140. ISSN 0004-637X. doi:10.3847/1538-4357/ac1c75.

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Through the Backyard Worlds: Planet 9 citizen science project, we have identified a wide-separation (∼10', ∼9900 au projected) substellar companion to the nearby (∼17.5 pc), mid-M dwarf Ross 19. We have developed a new formalism for determining chance alignment probabilities based on the BANYAN Σ tool, and find a 100% probability that this is a physically associated pair. Through a detailed examination of Ross 19A, we find that the system is metal-7.2^(+3.8)_(−3.6) poor ([Fe/H] = −0.40 ± 0.12) with an age of Gyr. Combining new and existing photometry and astrometry, we find that Ross 19B is one of the coldest known wide-separation companions, with a spectral type on the T/Y boundary, an effective temperature of 500^(+115)_(−100) K, and a mass in the range 15–40 M_(Jup). This new, extremely cold benchmark companion is a compelling target for detailed characterization with future spectroscopic observations using facilities such as the Hubble Space Telescope or James Webb Space Telescope.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Schneider, Adam C.0000-0002-6294-5937
Meisner, Aaron M.0000-0002-1125-7384
Gagné, Jonathan0000-0002-2592-9612
Faherty, Jacqueline K.0000-0001-6251-0573
Marocco, Federico0000-0001-7519-1700
Burgasser, Adam J.0000-0002-6523-9536
Kirkpatrick, J. Davy0000-0003-4269-260X
Kuchner, Marc J.0000-0002-2387-5489
Gramaize, Léopold0000-0002-8960-4964
Rothermich, Austin0000-0003-4083-9962
Brooks, Hunter0000-0002-5253-0383
Bardalez Gagliuffi, Daniella0000-0001-8170-7072
Caselden, Dan0000-0001-7896-5791
Cushing, Michael C.0000-0001-7780-3352
Line, Michael R.0000-0002-2338-476X
Casewell, Sarah L.0000-0003-2478-0120
Debes, John H.0000-0002-1783-8817
Aganze, Christian0000-0003-2094-9128
Gerasimov, Roman0000-0003-0398-639X
Gonzales, Eileen C.0000-0003-4636-6676
Hsu, Chih-Chun0000-0002-5370-7494
Kiman, Rocio0000-0003-2102-3159
Popinchalk, Mark0000-0001-9482-7794
Theissen, Christopher0000-0002-9807-5435
Additional Information:© 2021. The American Astronomical Society. Received 2021 June 25; revised 2021 July 30; accepted 2021 August 9; published 2021 November 9. The Backyard Worlds: Planet 9 team would like to thank the many Zooniverse volunteers who have participated in this project, from providing feedback during the beta review stage to classifying flipbooks to contributing to the discussions on TALK. We would also like to thank the Zooniverse web development team for their work creating and maintaining the Zooniverse platform and the Project Builder tools. This research was supported by NASA grant 2017-ADAP17-0067. This material is based upon work supported by the National Science Foundation under grant No. 2007068, 2009136, and 2009177. F.M. also acknowledges support from grant 80NSSC20K0452 under the NASA Astrophysics Data Analysis Program. E.G. acknowledges support from the Heising-Simons Foundation. (Some of) The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, and NEOWISE, which is a project of the Jet Propulsion Laboratory/California Institute of Technology. WISE and NEOWISE are funded by the National Aeronautics and Space Administration. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Software: crowdsource (Schlafly et al. 2018, 2019), BANYAN Σ (Gagné et al. 2018a), CoMover (Gagné et al. 2021), SEDkit (Filippazzo 2020), SpeXTool (Cushing et al. 2004).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Heising-Simons FoundationUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:Brown dwarfs; Low mass stars
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Brown dwarfs (185); Low mass stars (2050)
Record Number:CaltechAUTHORS:20211124-165131119
Persistent URL:
Official Citation:Adam C. Schneider et al 2021 ApJ 921 140
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112040
Deposited By: Tony Diaz
Deposited On:24 Nov 2021 18:49
Last Modified:24 Nov 2021 18:49

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