SDSS J141624.08+134826.7: BLUE L DWARFS AND NON-EQUILIBRIUM CHEMISTRY
- Jet Propulsion Laboratory, California Institute of Technology, MS 264-723, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
- Los Alamos National Laboratory, Applied Physics Division, MS F663, Los Alamos, NM 87545 (United States)
We present an analysis of the recently discovered blue L dwarf SDSS J141624.08+134826.7. We extend the spectral coverage of its published spectrum to {approx}4 {mu}m by obtaining a low-resolution L-band spectrum with SpeX on the NASA IRTF. The spectrum exhibits a tentative weak CH{sub 4} absorption feature at 3.3 {mu}m but is otherwise featureless. We derive the atmospheric parameters of SDSS J141624.08+134826.7 by comparing its 0.7-4.0 {mu}m spectrum to the atmospheric models of Marley and Saumon which include the effects of both condensate cloud formation and non-equilibrium chemistry due to vertical mixing and find the best-fitting model has T{sub eff} = 1700 K, log g = 5.5 (cm s{sup -2}), f{sub sed} = 4, and K{sub zz} = 10{sup 4} cm{sup 2} s{sup -1}. The derived effective temperature is significantly cooler than previously estimated but we confirm the suggestion by Bowler et al. that the peculiar spectrum of SDSS J141624.08+134826.7 is primarily a result of thin condensate clouds. In addition, we find strong evidence of vertical mixing in the atmosphere of SDSS J141624.08+134826.7 based on the absence of the deep 3.3 {mu}m CH{sub 4} absorption band predicted by models computed in chemical equilibrium. Finally, this result suggests that observations of blue L dwarfs are an appealing way to quantitatively estimate the vigor of mixing in the atmospheres of L dwarfs because of the dramatic impact such mixing has on the strength of the 3.3 {mu}m CH{sub 4} band in the emergent spectra of L dwarfs with thin condensate clouds.
- OSTI ID:
- 21443194
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 140, Issue 5; Other Information: DOI: 10.1088/0004-6256/140/5/1428; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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