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arXiv · 1012.0615

Spitzer Mid-Infrared Photometry of 500 - 750 K Brown Dwarfs

S. K. Leggett·L. Albert·E. Artigau·Ben Burningham·X. Delfosse·P. Delorme·T. Forveille·P. W. Lucas·M. S. Marley·D. J. Pinfield·C. Reyle·D. Saumon·R. L. Smart·S. J. Warren
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Abstract

Mid-infrared data, including Spitzer warm-IRAC [3.6] and [4.5] photometry, is critical for understanding the cold population of brown dwarfs now being found, objects which have more in common with planets than stars. As effective temperature (T_eff) drops from 800 K to 400 K, the fraction of flux emitted beyond 3 microns increases rapidly, from about 40% to >75%. This rapid increase makes a color like H-[4.5] a very sensitive temperature indicator, and it can be combined with a gravity- and metallicity-sensitive color like H-K to constrain all three of these fundamental properties, which in turn gives us mass and age for these slowly cooling objects. Determination of mid-infrared color trends also allows better exploitation of the WISE mission by the community. We use new Spitzer Cycle 6 IRAC photometry, together with published data, to present trends of color with type for L0 to T10 dwarfs. We also use the atmospheric and evolutionary models of Saumon & Marley to investigate the masses and ages of 13 very late-type T dwarfs, which have H-[4.5] > 3.2 and T_eff ~ 500 K to 750 K.

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S. K. Leggett, L. Albert, E. Artigau, Ben Burningham, X. Delfosse, P. Delorme, T. Forveille, P. W. Lucas, M. S. Marley, D. J. Pinfield, C. Reyle, D. Saumon, R. L. Smart, S. J. Warren. 2010-12-03. Spitzer Mid-Infrared Photometry of 500 - 750 K Brown Dwarfs. https://arxiv.org/abs/1012.0615

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