2022ApJ...938...56G -
Astrophys. J., 938, 56 (2022/October-2)
A Comparative L-dwarf Sample Exploring the Interplay between Atmospheric Assumptions and Data Properties.
GONZALES E.C., BURNINGHAM B., FAHERTY J.K., LEWIS N.K., VISSCHER C. and MARLEY M.
Abstract (from CDS):
Comparisons of atmospheric retrievals can reveal powerful insights on the strengths and limitations of our data and modeling tools. In this paper, we examine a sample of five L dwarfs of similar effective temperature (Teff) or spectral type to compare their pressure-temperature (P-T) profiles. Additionally, we explore the impact of an object's metallicity and the signal-to-noise ratio (S/N) of the observations on the parameters we can retrieve. We present the first atmospheric retrievals: 2MASS J15261405+2043414, 2MASS J05395200-0059019, 2MASS J15394189-0520428, and GD 165B increasing the small but growing number of L dwarfs retrieved. When compared to the atmospheric retrievals of SDSS J141624.08+134826.7, a low-metallicity d/sdL7 primary in a wide L+T binary, we find that similar Teff sources have similar P-T profiles with metallicity differences impacting the relative offset between their P-T profiles in the photosphere. We also find that for near-infrared spectra, when the S/N is ≳80 we are in a regime where model uncertainties dominate over data measurement uncertainties. As such, S/N does not play a role in the retrieval's ability to distinguish between a cloud-free and cloudless model, but may impact the confidence of the retrieved parameters. Lastly, we also discuss how to break cloud model degeneracies and the impact of extraneous gases in a retrieval model.
Abstract Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Brown dwarfs - Exoplanets - Atmospheric composition - Fundamental parameters of stars - L dwarfs - Stellar atmospheres - Metallicity
Simbad objects:
7
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