A Wide Planetary Mass Companion Discovered Through the Citizen Science Project Backyard Worlds: Planet 9
Jacqueline K. Faherty, Jonathan Gagne, Mark Popinchalk, Johanna M., Vos, Adam J. Burgasser, Jorg Schumann, Adam C. Schneider, J. Davy, Kirkpatrick, Aaron M. Meisner, Marc J. Kuchner, Daniella C. Bardalez, Gagliuffi, Federico Marocco, Dan Caselden, Eileen C. Gonzales, Austin

TL;DR
A citizen science project led to the discovery of a young, planetary-mass companion to a star, characterized by its red color, low gravity, and atmospheric features, with implications for understanding planetary formation.
Contribution
This study reports the first discovery of a wide planetary-mass companion through citizen science, including detailed characterization and analysis of its properties and system age.
Findings
Discovered a late-type L dwarf companion at 1662 AU separation.
Estimated the companion's mass to be approximately 15 Jupiter masses.
Confirmed the system's age to be between 50 and 150 million years.
Abstract
Through the Backyard Worlds: Planet 9 citizen science project we discovered a late-type L dwarf co-moving with the young K0 star BD+60 1417 at a projected separation of 37" or 1662 AU. The secondary - CWISER J124332.12+600126.2 (W1243) - is detected in both the CatWISE2020 and 2MASS reject tables. The photometric distance and CatWISE proper motion both match that of the primary within ~1sigma and our estimates for chance alignment yield a zero probability. Follow-up near infrared spectroscopy reveals W1243 to be a very red 2MASS color(J-Ks=2.72), low-surface gravity source that we classify as L6 - L8gamma. Its spectral morphology strongly resembles that of confirmed late-type L dwarfs in 10 - 150 Myr moving groups as well as that of planetary mass companions. The position on near- and mid-infrared color-magnitude diagrams indicates the source is redder and fainter than the field…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
Taxonomy
TopicsStellar, planetary, and galactic studies · Astronomy and Astrophysical Research · Astro and Planetary Science
