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http://hdl.handle.net/20.500.12386/33016
Title: | Cloud Atlas: Weak Color Modulations Due to Rotation in the Planetary-mass Companion GU Psc b and 11 Other Brown Dwarfs | Authors: | Lew, Ben W. P. Apai, Dániel Zhou, Yifan Radigan, Jacqueline Marley, Mark Schneider, Glenn Cowan, Nicolas B. Miles-Páez, Paulo A. Manjavacas, Elena Karalidi, Theodora BEDIN, Luigi Lowrance, Patrick J. Burgasser, Adam J. |
Issue Date: | 2020 | Journal: | THE ASTRONOMICAL JOURNAL | Number: | 159 | Issue: | 3 | First Page: | 125 | Abstract: | 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. | URI: | http://hdl.handle.net/20.500.12386/33016 | URL: | https://iopscience.iop.org/article/10.3847/1538-3881/ab5f59 https://api.elsevier.com/content/abstract/scopus_id/85085116303 |
ISSN: | 0004-6256 | DOI: | 10.3847/1538-3881/ab5f59 | Bibcode ADS: | 2020AJ....159..125L | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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Lew_2020_AJ_159_125.pdf | Pdf editoriale | 4.74 MB | Adobe PDF | View/Open |
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