WISEA J083011.95+283716.0: A Missing Link Planetary-mass Object
Daniella C. Bardalez Gagliuffi, Jacqueline K. Faherty, Adam C. Schneider, Aaron Meisner, Dan Caselden, Guillaume Colin, Sam Goodman, J. Davy Kirkpatrick, Marc Kuchner, Jonathan Gagné, Sarah E. Logsdon, Adam J. Burgasser, Katelyn Allers, John Debes, John Wisniewski, Austin Rothermich, Nikolaj Stevnbak Andersen, Melina Thévenot, Jim Walla
Abstract
Abstract We present the discovery of WISEA J083011.95+283716.0, the first Y-dwarf candidate identified through the “Backyard Worlds: Planet 9” citizen science project. We identified this object as a red, fast-moving source with a faint W 2 detection in multiepoch AllWISE and unWISE images. We have characterized this object with Spitzer and Hubble Space Telescope’s (HST) follow-up imaging. With mid-infrared detections in Spitzer's ch1 and ch2 bands and flux upper limits in HST F 105 W and F 125 W filters, we find that this object is both very faint and has extremely red colors ( ch 1 − ch 2 = 3.25 ± 0.23 mag, F 125 W − ch 2 ≥ 9.36 mag), consistent with a T eff ∼ 300 K source, as estimated from the known Y-dwarf population. A preliminary parallax provides a distance of pc, leading to a slightly warmer temperature of ∼350 K. The extreme faintness and red HST and Spitzer colors of this object suggest that it may be a link between the broader Y-dwarf population and the coldest known brown dwarf WISE J0855−0714, and may highlight our limited knowledge of the true spread of Y-dwarf colors. We also present four additional “Backyard Worlds: Planet 9” late-T brown dwarf discoveries within 30 pc.