Mid-infrared followup of cold brown dwarfs: Diversity in age, mass and metallicity

S. K. Leggett, B. Burningham, D. Saumon, M. S. Marley, S. J. Warren, H. R.A. Jones, D. J. Pinfield, R. L. Smart

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

We use Spitzer IRAC 3.6-8.0μm photometry of late-type T dwarfs to investigate various trends which can aid the planning and interpretation of infrared (IR) surveys for the coldest T or Y dwarfs. Brown dwarfs with effective temperature (Teff)<700K emit>50% of their flux at λ>3μm, and the ratio of the mid-IR to the near-IR flux becomes very sensitive to Teff. The color H - [4.5] is a good indicator of Teff with a weak dependence on metallicity ([m/H]) and gravity (g) while H -K and [4.5] - [5.8] are sensitive to [m/H] and g. Thus Teff and g can be constrained and mass and age can then be determined from evolutionary models. There are 12 dwarfs known with H - [4.5] > 3.0 and 500 TeffK 800, which we examine in detail. The ages of these dwarfs range from very young (0.1-1.0Gyr) to old (3-12Gyr). The mass range is possibly as low as 5 MJup to 70 MJup, and [m/H] also spans a large range of ∼ -0.3 to ∼ +0.3. The T8-T9 dwarfs found so far in the UKIRT IR Deep Sky Survey are unexpectedly young and low-mass. Extensions to the warm Spitzer and WISE space missions are needed to obtain mid-IR data for cold brown dwarfs, and to discover more of these rare objects.

Original languageEnglish (US)
Title of host publicationResearch, Science and Technology of Brown Dwarfs and Exoplanets
Subtitle of host publicationProceedings of an International Conference Held in Shangai on Occasion of a Total Eclipse of the Sun
EditorsWeipeng Lin, Eduardo L. Martin, Eduardo L. Martin, Jian Ge
PublisherEDP Sciences
ISBN (Electronic)9782759806645
DOIs
StatePublished - Jul 18 2011
Externally publishedYes
EventInternational Conference Held in Shangai on Occasion of a Total Eclipse of the Sun - Shanghai, China
Duration: Jul 20 2009Jul 24 2009

Publication series

NameEPJ Web of Conferences
Volume16
ISSN (Print)2101-6275
ISSN (Electronic)2100-014X

Other

OtherInternational Conference Held in Shangai on Occasion of a Total Eclipse of the Sun
Country/TerritoryChina
CityShanghai
Period7/20/097/24/09

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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