EXPLORING the ROLE of SUB-MICRON-SIZED DUST GRAINS in the ATMOSPHERES of RED L0-L6 DWARFS

Kay Hiranaka, Kelle L. Cruz, Stephanie T. Douglas, Mark S. Marley, Vivienne F. Baldassare

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

We examine the hypothesis that the red near-infrared colors of some L dwarfs could be explained by a "dust haze" of small particles in their upper atmospheres. This dust haze would exist in conjunction with the clouds found in dwarfs with more typical colors. We developed a model that uses Mie theory and the Hansen particle size distributions to reproduce the extinction due to the proposed dust haze. We apply our method to 23 young L dwarfs and 23 red field L dwarfs. We constrain the properties of the dust haze including particle size distribution and column density using Markov Chain Monte Carlo methods. We find that sub-micron-range silicate grains reproduce the observed reddening. Current brown dwarf atmosphere models include large-grain (1-100 μm) dust clouds but not sub-micron dust grains. Our results provide a strong proof of concept and motivate a combination of large and small dust grains in brown dwarf atmosphere models.

Original languageEnglish (US)
Article number96
JournalAstrophysical Journal
Volume830
Issue number2
DOIs
StatePublished - Oct 20 2016
Externally publishedYes

Keywords

  • brown dwarfs
  • dust, extinction

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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