SIMBAD references

2020AJ....159..125L - Astron. J., 159, 125-125 (2020/March-0)

Cloud atlas: weak color modulations due to rotation in the planetary-mass companion GU Psc b and 11 other brown dwarfs.

LEW B.W.P., APAI D., ZHOU Y., RADIGAN J., MARLEY M., SCHNEIDER G., COWAN N.B., MILES-PAEZ P.A., MANJAVACAS E., KARALIDI T., BEDIN L.R., LOWRANCE P.J. and BURGASSER A.J.

Abstract (from CDS):

Among the greatest challenges in understanding ultracool brown dwarf and exoplanet atmospheres is the evolution of cloud structure as a function of temperature and gravity. In this study, we present the rotational modulations of GU Psc b-a rare mid-T spectral type planetary-mass companion at the end of the L/T spectral type transition. Based on the Hubble Space Telescope/WFC3 1.1-1.67 µm time-series spectra, we observe a quasi-sinusoidal light curve with a peak-to-trough flux variation of 2.7% and a minimum period of 8 h. The rotation-modulated spectral variations are weakly wavelength-dependent, or largely gray between 1.1 and 1.67 µm. The gray modulations indicate that heterogeneous clouds are present in the photosphere of this low-gravity mid-T dwarf. We place the color and brightness variations of GU Psc b in the context of rotational modulations reported for mid-L to late-T dwarfs. Based on these observations, we report a tentative trend: mid-to-late T dwarfs become slightly redder in J - H color with increasing J-band brightness, while L dwarfs become slightly bluer with increasing brightness. If this trend is verified with more T-dwarf samples, it suggests that in addition to the mostly gray modulations, there is a second-order spectral-type dependence on the nature of rotational modulations.

Abstract Copyright: © 2020. The American Astronomical Society. All rights reserved.

Journal keyword(s): Brown dwarfs - Exoplanet atmospheres - Planetary atmospheres - Exoplanet atmospheric variability - T dwarfs

Simbad objects: 18

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2021.06.23-17:06:09

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