2002ApJ...577..986B -
Astrophys. J., 577, 986-992 (2002/October-1)
New CrH opacities for the study of l and brown dwarf atmospheres.
BURROWS A., RAM R.S., BERNATH P., SHARP C.M. and MILSOM J.A.
Abstract (from CDS):
In this paper, we calculate new line lists and opacities for the 12 bands of the A6Σ+-X6Σ+ transitions of the CrH molecule. Identified in objects of the new L dwarf spectroscopic class (many of which are brown dwarfs), as well as in sunspots, the CrH molecule plays an important role in the diagnosis of low-temperature atmospheres. As a tentative first application of these opacities, we employ our new theoretical CrH data in an atmospheres code to obtain a CrH/H2number ratio for the skin of the L5 dwarf 2MASSI J1507038-151648 of ~(2-4)x10–9, in rough agreement with chemical equilibrium expectations. Since in previous compilations the oscillator strength was off by more than an order of magnitude, this agreement represents a modest advance. However, in order to fit the CrH abundance in the L dwarf spectral class, silicate clouds need to be incorporated into the model. Given that this subject is still in a primitive stage of development, one should view any spectral model in the L dwarf range as merely tentative. Nevertheless, a necessary first step in L dwarf modeling is a reliable CrH opacity algorithm, and this is what we have here attempted to provide.
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Journal keyword(s):
Astrochemistry - Infrared: Stars - Molecular Data - Stars: Atmospheres - Stars: Fundamental Parameters - Stars: Low-Mass, Brown Dwarfs
Simbad objects:
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