Model atmospheres and spectra: The role of dust

Forskningsoutput: Kapitel i bok/rapport/Conference proceedingKonferenspaper i proceeding

Abstract

Brown dwarf atmospheres form molecules, then high temperature condensates (corundum, titanates, silicates, and iron compounds), and then low temperature condensates (ices) as they cool down over time. These produce large opacities which govern entirely their spectral energy distribution. Just as it is important to know molecular opacities (TiO, H2O, CH4, etc.) with accuracy, it is imperative to understand the interplay of processes (e.g. condensation, sedimentation, coagulation, convection) that determines the radial and size distribution of grains. Limiting case models have shown that young, hot brown (L) dwarfs form dust mostly in equilibrium, while at much cooler stages (late T dwarfs) all high temperature condensates have sedimented out of their photospheres. But this process is gradual and all intermediate classes of brown dwarfs can partly be understood in terms of partial sedimentation of dust. With new models accounting for these processes, we describe the effects they may have upon brown dwarf spectral properties.

Detaljer

Författare
  • F Allard
  • T Guillot
  • Hans-Günter Ludwig
  • P H Hauschildt
  • A Schweitzer
  • DR Alexander
  • JW Ferguson
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Astronomi, astrofysik och kosmologi
Originalspråkengelska
Titel på värdpublikationProceedings of the International Astronomical Union (Brown Dwarfs)
RedaktörerEduardo L. Martín
FörlagAstronomical Society of the Pacific (ASP)
Sidor325-332
Volym211
ISBN (tryckt)ISBN:1-58381-132-X
StatusPublished - 2003
PublikationskategoriForskning
Peer review utfördJa
Evenemang211th Symposium of the International Astronomical Union - Outrigger Waikoloa Beach Hotel Waikoloa, Hawaii, USA
Varaktighet: 2002 maj 202002 maj 24

Publikationsserier

Namn
Volym211
ISSN (tryckt)0074-1809

Konferens

Konferens211th Symposium of the International Astronomical Union
LandUSA
OrtOutrigger Waikoloa Beach Hotel Waikoloa, Hawaii
Period2002/05/202002/05/24