We report the identification of 89 new systems containing ultracool dwarf companions to main-sequence stars and white dwarfs, using the citizen science project Backyard Worlds: Planet 9 and cross-reference between Gaia and CatWISE2020. 32 of these companions and 33 host stars were followed up with spectroscopic observations, with companion spectral types ranging from M7–T9 and host spectral types ranging from G2–M9. These systems exhibit diverse characteristics, from young to old ages, blue to very red spectral morphologies, potential membership to known young moving groups, and evidence of spectral binarity in nine companions. 20 of the host stars in our sample show evidence for higher-order multiplicity, with an additional 11 host stars being resolved binaries themselves. We compare this sample's characteristics with those of the known stellar binary and exoplanet populations, and find our sample begins to fill in the gap between directly imaged exoplanets and stellar binaries on mass ratio–binding energy plots. With this study, we increase the population of ultracool dwarf companions to FGK stars by ∼42%, and more than triple the known population of ultracool dwarf companions with separations larger than 1000 au, providing excellent targets for future atmospheric retrievals.
89 New Ultracool Dwarf Comoving Companions Identified with the Backyard Worlds: Planet 9 Citizen Science Project
- Creators
- Rothermich, Austin
- Faherty, Jacqueline K.
- Bardalez-Gagliuffi, Daniella
- Schneider, Adam C.
- Kirkpatrick, J. Davy1
- Meisner, Aaron M.
- Burgasser, Adam J.
- Kuchner, Marc
- Allers, Katelyn
- Gagné, Jonathan
- Caselden, Dan
- Calamari, Emily
- Popinchalk, Mark
- Suárez, Genaro
- Gerasimov, Roman
- Aganze, Christian
- Softich, Emma
- Hsu, Chin-Chun
- Karpoor, Preethi
- Theissen, Christopher A.
- Rees, Jon
- Cecilio-Flores-Elie, Rosario
- Cushing, Michael C.
- Marocco, Federico
- Casewell, Sarah
- Bickle, Thomas P.
- Hamlet, Les
- Allen, Michaela B.
- Beaulieu, Paul
- Colin, Guillaume
- Gantier, Jean Marc
- Gramaize, Leopold
- Jalowiczor, Peter
- Kabatnik, Martin
- Kiwy, Frank
- Martin, David W.
- Pendrill, Billy
- Pumphrey, Ben
- Sainio, Arttu
- Schumann, Jorg
- Stevnbak, Nikolaj
- Sun, Guoyou
- Tanner, Christopher
- Thakur, Vinod
- Thevenot, Melina
- Wedracki, Zbigniew
Abstract
Copyright and License
© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
he authors would like to thank the numerous citizen scientist volunteers of the Backyard Worlds: Planet 9 project for their hard work, dedication, and contributions to this paper.
The authors acknowledge support from NASA award #80NSSC21K0402 and NASA ADAP award #80NSSC22K0491 as well as NSF award #2009177. J.F. acknowledges support from the Heising-Simons foundation. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. Based in part on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia e Inovações (MCTI/LNA) do Brasil, the US National Science Foundation's NOIRLab, the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c)3 nonprofit organization 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. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Some of the observations reported in this paper were obtained with the Southern African Large Telescope (SALT). This work presents results from the European Space Agency (ESA) space mission Gaia. Gaia data are being processed by the Gaia Data Processing and Analysis Consortium (DPAC). Funding for the DPAC is provided by national institutions, in particular the institutions participating in the Gaia MultiLateral Agreement (MLA). The Gaia mission website is https://www.cosmos.esa.int/gaia. The Gaia archive website is https://archives.esac.esa.int/gaia. 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, funded by the National Aeronautics and Space Administration.
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Additional details
- ISSN
- 1538-3881
- National Aeronautics and Space Administration
- 80NSSC21K0402
- National Aeronautics and Space Administration
- 80NSSC22K0491
- National Science Foundation
- AST-2009177
- Heising-Simons Foundation
- W. M. Keck Foundation
- European Space Agency
- Gaia Multilateral Agreement
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)