Redder than Red: Discovery of an Exceptionally Red L/T Transition Dwarf

Creators: Schneider, Adam C.; Burgasser, Adam J.; Bruursema, Justice; Munn, Jeffrey A.; Vrba, Frederick J.; Caselden, Dan; Kabatnik, Martin; Rothermich, Austin; Sainio, Arttu; Bickle, Thomas P.; Dahm, Scott E.; Meisner, Aaron M.; Kirkpatrick, J. Davy; Suárez, Genaro; Gagné, Jonathan; Faherty, Jacqueline K.; Vos, Johanna M.; Kuchner, Marc J.; Williams, Stephen J.; Bardalez Gagliuffi, Daniella; Aganze, Christian; Hsu, Chih-Chun; Theissen, Christopher; Cushing, Michael C.; Marocco, Federico; Casewell, Sarah L.; Backyard Worlds: Planet 9 Collaboration

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)_(MKO) color of 2.97 ± 0.03 mag and a J_(MKO) − 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 CH₄ absorption 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 3–5 μm 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 the β Pic moving group. A future parallax measurement will help to establish a more definitive moving group membership for this unusual object.

Additional Information

© 2023. 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. The Backyard Worlds: Planet 9 team would like to thank the many Zooniverse volunteers who have participated in this project. 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 supported by the National Science Foundation under grant No. 2007068, 2009136, and 2009177. This publication makes use of data products from the UKIRT Hemisphere Survey, which is a joint project of the United States Naval Observatory, The University of Hawaii Institute for Astronomy, the Cambridge University Cambridge Astronomy Survey Unit, and the University of Edinburgh Wide-Field Astronomy Unit (WFAU). UHS is primarily funded by the United States Navy. The WFAU gratefully acknowledges support for this work from the Science and Technology Facilities Council through ST/T002956/1 and previous grants. The authors acknowledge the support provided by the US Naval Observatory in the areas of celestial and reference frame research, including the USNO's postdoctoral program. (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. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has benefitted from the SpeX Prism Spectral Libraries, maintained by Adam Burgasser. 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. Facilities: UKIRT/WFCAM, Keck/NIRES, WISE, NEOWISE. Software: BANYAN Σ (Gagné et al. 2018a), CASUTOOLS (Irwin et al. 2004), LACEwING (Riedel et al. 2017), SpeXTool (Cushing et al. 2004), SPLAT (Burgasser 2014), WiseView (Caselden et al. 2018).

Attached Files

Published - Schneider_2023_ApJL_943_L16.pdf

Files

Schneider_2023_ApJL_943_L16.pdf

Files (5.6 MB)

Name	Size	Download all
Schneider_2023_ApJL_943_L16.pdf md5:9bee2114d6f60c5efdb69a8f495c7087	5.6 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes