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Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project

Meisner, Aaron M. and Faherty, Jacqueline K. and Kirkpatrick, J. Davy and Schneider, Adam C. and Caselden, Dan and Gagné, Jonathan and Kuchner, Marc J. and Burgasser, Adam J. and Casewell, Sarah L. and Debes, John H. and Artigau, Étienne and Bardalez Gagliuffi, Daniella C. and Logsdon, Sarah E. and Kiman, Rocio and Allers, Katelyn and Hsu, Chih-chun and Wisniewski, John P. and Allen, Michaela B. and Beaulieu, Paul and Colin, Guillaume and Durantini Luca, Hugo A. and Goodman, Sam and Gramaize, Léopold and Hamlet, Leslie K. and Hinckley, Ken and Kiwy, Frank and Martin, David W. and Pendrill, William and Rothermich, Austin and Sainio, Arttu and Schümann, Jörg and Andersen, Nikolaj Stevnbak and Tanner, Christopher and Thakur, Vinod and Thévenot, Melina and Walla, Jim and Wędracki, Zbigniew and Aganze, Christian and Gerasimov, Roman and Theissen, Christopher (2020) Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project. Astrophysical Journal, 899 (2). Art. No. 123. ISSN 1538-4357. doi:10.3847/1538-4357/aba633.

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We present Spitzer follow-up imaging of 95 candidate extremely cold brown dwarfs discovered by the Backyard Worlds: Planet 9 citizen science project, which uses visually perceived motion in multiepoch Wide-field Infrared Survey Explorer (WISE) images to identify previously unrecognized substellar neighbors to the Sun. We measure Spitzer [3.6]–[4.5] color to phototype our brown dwarf candidates, with an emphasis on pinpointing the coldest and closest Y dwarfs within our sample. The combination of WISE and Spitzer astrometry provides quantitative confirmation of the transverse motion of 75 of our discoveries. Nine of our motion-confirmed objects have best-fit linear motions larger than 1'' yr⁻¹; our fastest-moving discovery is WISEA J155349.96+693355.2 (μ ≈ 2.”15 yr⁻¹), a possible T-type subdwarf. We also report a newly discovered wide-separation (~400 au) T8 comoving companion to the white dwarf LSPM J0055+5948 (the fourth such system to be found), plus a candidate late T companion to the white dwarf LSR J0002+6357 at 5 5 projected separation (~8700 au if associated). Among our motion-confirmed targets, five have Spitzer colors most consistent with spectral type Y. Four of these five have exceptionally red Spitzer colors suggesting types of Y1 or later, adding considerably to the small sample of known objects in this especially valuable low-temperature regime. Our Y dwarf candidates begin bridging the gap between the bulk of the Y dwarf population and the coldest known brown dwarf.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Meisner, Aaron M.0000-0002-1125-7384
Faherty, Jacqueline K.0000-0001-6251-0573
Kirkpatrick, J. Davy0000-0003-4269-260X
Schneider, Adam C.0000-0002-6294-5937
Caselden, Dan0000-0001-7896-5791
Gagné, Jonathan0000-0002-2592-9612
Kuchner, Marc J.0000-0002-2387-5489
Burgasser, Adam J.0000-0002-6523-9536
Casewell, Sarah L.0000-0003-2478-0120
Debes, John H.0000-0002-1783-8817
Artigau, Étienne0000-0003-3506-5667
Bardalez Gagliuffi, Daniella C.0000-0001-8170-7072
Logsdon, Sarah E.0000-0002-9632-9382
Kiman, Rocio0000-0003-2102-3159
Allers, Katelyn0000-0003-0580-7244
Hsu, Chih-chun0000-0002-5370-7494
Wisniewski, John P.0000-0001-9209-1808
Colin, Guillaume0000-0002-7630-1243
Durantini Luca, Hugo A.0000-0002-4143-2550
Goodman, Sam0000-0003-2236-2320
Gramaize, Léopold0000-0002-8960-4964
Hamlet, Leslie K.0000-0002-7389-2092
Hinckley, Ken0000-0002-4733-4927
Kiwy, Frank0000-0001-8662-1622
Rothermich, Austin0000-0003-4083-9962
Sainio, Arttu0000-0003-4864-5484
Schümann, Jörg0000-0002-7587-7195
Andersen, Nikolaj Stevnbak0000-0003-4714-3829
Tanner, Christopher0000-0002-9807-5435
Thévenot, Melina0000-0001-5284-9231
Theissen, Christopher0000-0002-9807-5435
Additional Information:© 2020 The American Astronomical Society. Received 2020 May 22; revised 2020 June 29; accepted 2020 June 30; published 2020 August 20. We thank the anonymous referee for valuable comments. The Backyard Worlds: Planet 9 team would like to thank the many Zooniverse volunteers who have participated in this project, from providing feedback during the beta review stage to classifying flipbooks to contributing to the discussions on TALK. 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. S.L.C. acknowledges the support of an STFC Ernest Rutherford Fellowship. Support for this work was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51447.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. 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. This research has made use of the NASA/IPAC Infrared Science Archive, which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology. This research has made use of the VizieR catalog access tool, CDS, Strasbourg, France (DOI :10.26093/cds/vizier). The original description of the VizieR service was published in Ochsenbein et al. (2000). This work has made use of the white dwarf cooling models hosted by Pierre Bergeron at Facilities: Spitzer(IRAC) - Spitzer Space Telescope satellite, HST(WFC3) - , WISE/NEOWISE - , UKIRT(WFCAM) - , VISTA(VIRCAM) - , IRSA - , 2MASS - , Gaia - . Software: MOPEX (Makovoz & Khan 2005; Makovoz & Marleau 2005), WiseView (Caselden et al. 2018), (Lang et al. 2010).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)UNSPECIFIED
NASA Hubble FellowshipHST-HF2-51447.001-A
Subject Keywords:Y dwarfs ; Brown dwarfs ; T dwarfs ; Visual binary stars ; Proper motions ; Solar neighborhood ; Infrared astronomy
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Y dwarfs (1827); Brown dwarfs (185); T dwarfs (1679); Visual binary stars (1777); Proper motions (1295); Solar neighborhood (1509); Infrared astronomy (786)
Record Number:CaltechAUTHORS:20200824-065903851
Persistent URL:
Official Citation:Aaron M. Meisner et al 2020 ApJ 899 123
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105063
Deposited By: Tony Diaz
Deposited On:24 Aug 2020 16:24
Last Modified:16 Nov 2021 18:39

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