Evidence of cloud disruption in the L/T dwarf transition

Adam J. Burgasser, Mark S. Marley, Andrew S. Ackerman, Didier Saumon, Katharina Lodders, Conard C. Dahn, Hugh C. Harris, J. Davy Kirkpatrick

Research output: Contribution to journalArticlepeer-review

159 Scopus citations

Abstract

Clouds of metal-bearing condensates play a critical role in shaping the emergent spectral energy distributions of the coolest classes of low-mass stars and brown dwarfs, L and T dwarfs. Because condensate clouds in planetary atmospheres show distinct horizontal structure, we have explored a model for partly cloudy atmospheres in brown dwarfs. Our model successfully reproduces the colors and magnitudes of both L and T dwarfs for the first time, including the unexpected brightening of the early- and mid-type T dwarfs at the J band, provided that clouds are rapidly removed from the photosphere at T eff ≈ 1200 K. The clearing of cloud layers also explains the surprising persistence and strengthening of gaseous FeH bands in early- and mid-type T dwarfs. The breakup of cloud layers is likely driven by convection in the troposphere, analogous to phenomena observed on Jupiter. Our results demonstrate that planetary-like atmospheric dynamics must be considered when examining the evolution of free-floating brown dwarfs.

Original languageEnglish (US)
Pages (from-to)L151-L154
JournalAstrophysical Journal
Volume571
Issue number2 II
DOIs
StatePublished - Jun 1 2002
Externally publishedYes

Keywords

  • Infrared: stars
  • Stars: atmospheres
  • Stars: fundamental parameters
  • Stars: individual (SDSS J1254-0122, 2MASS J0559-1404)
  • Stars: low-mass, brown dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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