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The Luminosities of the Coldest Brown Dwarfs

Tinney, C. G. and Faherty, Jacqueline K. and Kirkpatrick, J. Davy and Cushing, Mike and Morley, Caroline V. and Wright, Edward L. (2014) The Luminosities of the Coldest Brown Dwarfs. Astrophysical Journal, 796 (1). Art. No. 39. ISSN 0004-637X.

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In recent years, brown dwarfs have been extended to a new Y-dwarf class with effective temperatures colder than 500 K and masses in the range of 5-30 Jupiter masses. They fill a crucial gap in observable atmospheric properties between the much colder gas-giant planets of our own solar system (at around 130 K) and both hotter T-type brown dwarfs and the hotter planets that can be imaged orbiting young nearby stars (both with effective temperatures in the range of 1500-1000 K). Distance measurements for these objects deliver absolute magnitudes that make critical tests of our understanding of very cool atmospheres. Here we report new distances for nine Y dwarfs and seven very late T dwarfs. These reveal that Y dwarfs do indeed represent a continuation of the T-dwarf sequence to both fainter luminosities and cooler temperatures. They also show that the coolest objects display a large range in absolute magnitude for a given photometric color. The latest atmospheric models show good agreement with the majority of these Y-dwarf absolute magnitudes. This is also the case for WISE0855-0714, the coldest and closest brown dwarf to the Sun, which shows evidence for water ice clouds. However, there are also some outstanding exceptions, which suggest either binarity or the presence of condensate clouds. The former is readily testable with current adaptive optics facilities. The latter would mean that the range of cloudiness in Y dwarfs is substantial with most hosting almost no clouds—while others have dense clouds, making them prime targets for future variability observations to study cloud dynamics.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Tinney, C. G.0000-0002-7595-0970
Faherty, Jacqueline K.0000-0001-6251-0573
Kirkpatrick, J. Davy0000-0003-4269-260X
Cushing, Mike0000-0001-7780-3352
Morley, Caroline V.0000-0002-4404-0456
Wright, Edward L.0000-0001-5058-1593
Additional Information:© 2014 American Astronomical Society. Received 2014 July 8; accepted 2014 October 2; published 2014 November 4. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. Australian access to the Magellan Telescopes was supported through the National Collaborative Research Infrastructure and Collaborative Research Infrastructure Strategies of the Australian Federal Government. Access through the Chilean Time Allocation Committee was supported by awards CN2012A-011, CN2012B-057, CN2013A-127. This research was supported by Australian Research Council grants DP0774000 and DP130102695. This publication makes use of data products from the Wide-field Infrared Survey Explorer (WISE), 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 US National Aeronautics and Space Administration. Facilities: Magellan:Baade (FourStar), WISE
Funding AgencyGrant Number
Chilean Time Allocation CommitteeCN2012A-011
Chilean Time Allocation CommitteeCN2012B-057
Chilean Time Allocation CommitteeCN2013A-127
Australian Research CouncilDP0774000
Australian Research CouncilDP130102695
Subject Keywords:brown dwarfs; parallaxes; planetary systems; stars: distances
Issue or Number:1
Record Number:CaltechAUTHORS:20141211-103409607
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Official Citation:The Luminosities of the Coldest Brown Dwarfs C. G. Tinney et al. 2014 ApJ 796 39
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52597
Deposited By: Ruth Sustaita
Deposited On:11 Dec 2014 21:23
Last Modified:09 Mar 2020 13:19

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