The Role of Dust and Non-Equilibrium Chemistry in the Atmospheres of L and T Dwarfs as Constrained by Spitzer IRS and IRAC Observations

Details The Role of Dust and Non-Equilibrium Chemistry in the Atmospheres of L and T Dwarfs as Constrained by Spitzer IRS and IRAC Observations The Role of Dust and Non-Equilibrium Chemistry in the Atmospheres of L and T Dwarfs as Constrained by Spitzer IRS and IRAC Observations

May 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006sptz.prop30140m&link_type=abstract

Spitzer Proposal ID #30140

Physics

Scientific paper

We propose to instensively study the physical processes that can affect the mid-infrared spectra and colors of L- and T-type brown dwarfs as observed by Spitzer. In particular we will modify our current atmosphere structure and spectral models of these objects to understand the origin of the unexpected flattening seen at 8 to 10 microns in IRS spectra of mid L-type objects. This flattening is likely due to a larger abundance of small silicate grains in the L dwarf clouds than predicted by our model. By producing a large number of models with a variety of grain sizes and compositions (enstatite, forsterite, and possibly quartz, including both crystalline and amorphous phases) we expect to constrain the composition and vertical structure of L dwarf cloud layers. We will also explore the role of non-equilibrium chemistry driven by atmospheric mixing in affecting the abundances of CO and ammonia in late L and T dwarf atmospheres. Excess CO lowers the flux in IRAC band 2 below that predicted by models that assume equilibrium chemistry and makes cool brown dwarfs more difficult to detect than predicted by equilibriium models (an important point for surveys aiming at detecting T and Y dwarfs). Lower than expected ammonia abundances are apparent in the shape of the ammonia absorption feature seen in IRS spectra at 10 microns.

Affiliated with

Also associated with

No associations

Rating

The Role of Dust and Non-Equilibrium Chemistry in the Atmospheres of L and T Dwarfs as Constrained by Spitzer IRS and IRAC Observations 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 Role of Dust and Non-Equilibrium Chemistry in the Atmospheres of L and T Dwarfs as Constrained by Spitzer IRS and IRAC Observations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Role of Dust and Non-Equilibrium Chemistry in the Atmospheres of L and T Dwarfs as Constrained by Spitzer IRS and IRAC Observations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-933043