The Cloudy Atmospheres of Brown Dwarfs: Lessons for Direct Detection of Extrasolar Giant Planets

Details The Cloudy Atmospheres of Brown Dwarfs: Lessons for Direct Detection of Extrasolar Giant Planets The Cloudy Atmospheres of Brown Dwarfs: Lessons for Direct Detection of Extrasolar Giant Planets

Sep 1999

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999dps....31.0203m&link_type=abstract

American Astronomical Society, DPS meeting #31, #02.03

Astronomy and Astrophysics

Astronomy

Scientific paper

Brown dwarfs are pathfinders to the era of direct detection and interpretation of extrasolar giant planets. As with our own giant planets, one of the more vexing issues in understanding these objects is the role of clouds. Dusty condensate clouds play an increasingly important role in controlling the thermal emission spectra of brown dwarfs with effective temperatures warmer than about 1300 K. Atmospheres with Teff near 2000 K are perhaps the dustiest. Coincidentally this is the same effective temperature range where atmospheric carbon transitions from CH_4 to CO. At lower effective temperatures there are few major condensates until water clouds appear in atmospheres with Teff below about 500 K. Thus we can divide the atmospheres of brown dwarfs into three broad classes: (1) hot, CO-rich, dusty atmospheres (e.g. Kelu-1); (2) warm, exceptionally clear (flux from 100 bars can be detected for 30 M_J objects), CH_4-dominated atmospheres (e.g. Gliese 229B); and (3) cooler, CH_4-rich atmospheres with icy condensate clouds like Jupiter (e.g. upsilon -And d, but no direct extrasolar detections, yet). The newly-coined ``L'' stellar classification spectral type roughly corresponds to class (1). We have computed model spectra of extrasolar giant planets and brown dwarfs with 200 < Teff < 2000 K with and without clouds. It is becoming increasingly clear from this work and the growing sample of brown dwarf spectra that an adequate understanding of the first class of objects, and thus the abundant L-dwarfs, requires input from cloud microphysical models. We will present the signature of various cloud models and discuss the need for additional detailed microphysical modeling. Lessons for detecting and then interpreting the spectra of extrasolar giant planets will be considered. Work supported by the NASA Planetary Atmospheres and MURED and NSF CAREER programs.

Affiliated with

Also associated with

No associations

Rating

The Cloudy Atmospheres of Brown Dwarfs: Lessons for Direct Detection of Extrasolar Giant Planets does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Cloudy Atmospheres of Brown Dwarfs: Lessons for Direct Detection of Extrasolar Giant Planets, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Cloudy Atmospheres of Brown Dwarfs: Lessons for Direct Detection of Extrasolar Giant Planets will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1554506