J/AJ/164/239ivo://CDS.VizieR/J/AJ/164/239doi:10.26093/cds/vizier.51640239CDSZhou Y.Bowler B.P.Apai D.Kataria T.Morley C.V.Bryan M.L.,Skemer A.J.,Benneke B.2023-03-29T13:17:06Z2023-02-10T06:52:42ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frexoplanetsbrown-dwarfsinfrared-astronomyspectroscopyThe photometric and spectral variability of brown dwarfs probes heterogeneous temperature and cloud distributions and traces the atmospheric circulation patterns. We present a new 42hr Hubble Space Telescope (HST) Wide Field Camera 3 G141 spectral time series of VHS1256-1257b, a late L-type planetary-mass companion that has been shown to have one of the highest variability amplitudes among substellar objects. The light curve is rapidly evolving and best fit by a combination of three sine waves with different periods and a linear trend. The amplitudes of the sine waves and the linear slope vary with the wavelength, and the corresponding spectral variability patterns match the predictions by models invoking either heterogeneous clouds or thermal profile anomalies. Combining these observations with previous HST monitoring data, we find that the peak-to-valley flux difference is 33%{+/-}2% with an even higher amplitude reaching 38% in the J band, the highest amplitude ever observed in a substellar object. The observed light curve can be explained by maps that are composed of zonal waves, spots, or a mixture of the two. Distinguishing the origin of rapid light curve evolution requires additional long-term monitoring. Our findings underscore the essential role of atmospheric dynamics in shaping brown-dwarf atmospheres and highlight VHS1256-1257b as one of the most favorable targets for studying the atmospheres, clouds, and atmospheric circulation of planets and brown dwarfs.2022AJ....164..239Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/164/239CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/814/65 : Jupiter HST light curves (Karalidi+, 2015)J/ApJS/225/10 : Kinematic analysis of M7-L8 dwarfs (Faherty+, 2016)J/ApJ/818/176 : HST/WFC3 NIR photometry of 2M1207b (Zhou+, 2016)J/A+A/629/A145 : L9-T3.5 brown dwarfs light curves (Eriksson+, 2019)J/AJ/160/63 : IR spectra of 5 brown dwarfs Gemini North IRS (Miles+, 2020)J/AJ/160/38 : Spitzer variability detections of 79 brown dwarfs (Vos+, 2020)J/AJ/161/42 : Volume-limited sample cool dwarfs I L0-T8 dwarfs (Best+, 2021)J/AJ/164/143 : Spectroscopy HR8799 planets with SCExAO/CHARIS (Wang+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/164/239https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/164/239http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/164/239https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/164/239https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/164/239http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/164/239GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap1.2674828593606592e-19 1.6013215698023027e-19InfrareddefaultJ/AJ/164/239/fig8*Combined light curves of VHS 1256 b in the 2018 and 2020 epochsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[2458183/2458998] Julian date of observationdtime.epochdoubleEpoch[2018/2020] Epoch, 2018 or 2022yrtime.epochintG141[3e-13/5e-13] HST/WFC3 G141 grism broadband flux density1000W.m**-3phot.flux.density;em.IR.Jdoublee_G141[5e-16/8e-16] Uncertainty in G1411000W.m**-3stat.errordoubleF127M[3e-13/5e-13] HST/WFC3 F127M filter flux density1000W.m**-3phot.flux.density;em.IR.Jdoublee_F127M[1e-15/3e-15] Uncertainty in F127M1000W.m**-3stat.errordoubleF139M[1e-13/3e-13] HST/WFC3 F139M filter flux density1000W.m**-3phot.flux.density;em.IR.Jdoublee_F139M[1e-15/2e-15] Uncertainty in F139M1000W.m**-3stat.errordoubleF153M[3e-13/5e-13] HST/WFC3 F153M filter flux density1000W.m**-3phot.flux.density;em.IR.Hdoublee_F153M[1e-15/2e-15] Uncertainty in F153M1000W.m**-3stat.errordouble