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Title: Redder than Red: Discovery of an Exceptionally Red L/T Transition Dwarf
Abstract We present the discovery of CWISE J050626.96+073842.4 (CWISE J0506+0738), an L/T transition dwarf with extremely red near-infrared colors discovered through the Backyard Worlds: Planet 9 citizen science project. Photometry from UKIRT and CatWISE give a (J−K)MKOcolor of 2.97 ± 0.03 mag and aJMKO− W2 color of 4.93 ± 0.02 mag, making CWISE J0506+0738 the reddest known free-floating L/T dwarf in both colors. We confirm the extremely red nature of CWISE J0506+0738 using Keck/NIRES near-infrared spectroscopy and establish that it is a low-gravity, late-type L/T transition dwarf. The spectrum of CWISE J0506+0738 shows possible signatures of CH4absorption in its atmosphere, suggesting a colder effective temperature than other known, young, red L dwarfs. We assign a preliminary spectral type for this source of L8γ–T0γ. We tentatively find that CWISE J0506+0738 is variable at 3–5μm based on multiepoch WISE photometry. Proper motions derived from follow-up UKIRT observations combined with a radial velocity from our Keck/NIRES spectrum and a photometric distance estimate indicate a strong membership probability in theβPic moving group. A future parallax measurement will help to establish a more definitive moving group membership for this unusual object.  more » « less
Award ID(s):
2009177 2009136
PAR ID:
10468215
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; ; ; « less
Publisher / Repository:
The Astrophysical Journal Letters
Date Published:
Journal Name:
The Astrophysical Journal Letters
Volume:
943
Issue:
2
ISSN:
2041-8205
Page Range / eLocation ID:
L16
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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