Weather on Other Worlds. VI. Optical Spectrophotometry of Luhman 16B Reveals Large-amplitude Variations in the Alkali Lines

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dc.contributor.authorHeinze, A. N.
dc.contributor.authorMetchev, Stanimir
dc.contributor.authorKurtev, Radostin
dc.contributor.authorGillon, Michael
dc.date.accessioned2022-11-30T02:46:25Z
dc.date.available2022-11-30T02:46:25Z
dc.date.issued2021
dc.description.abstractUsing a novel wide-slit, multiobject approach with the GMOS spectrograph on the 8 m Gemini South telescope, we have obtained precise time-series spectrophotometry of the binary brown dwarf Luhman 16 at optical wavelengths over two full nights. The B component of this binary system is known to be variable in the red optical and near-infrared with a period of 5 hr and an amplitude of 5%–20%. Our observations probe its spectrally resolved variability in the 6000–10000 Å range. At wavelengths affected by the extremely strong, broadened spectral lines of the neutral alkali metals (the potassium doublet centered near 7682 Å and the sodium doublet at 5893 Å), we see photometric variations that differ strikingly from those of the 8000–10000 Å "red continuum" that dominates our detected flux. On UT 2014 February 24, these variations are anticorrelated with the red continuum, while on February 25 they have a large relative phase shift. The extent to which the wavelength-dependent photometric behavior diverges from that of the red continuum appears to correlate with the strength of the alkali absorption. We consider but ultimately reject models in which our observations are explained by lightning or auroral activity. A more likely cause is cloud-correlated, altitude-dependent variations in the gas-phase abundances of sodium and potassium, which are in chemical equilibrium with their chlorides in brown dwarf atmospheres. Clouds could influence these chemical equilibria by changing the atmospheric temperature profile and/or through cloud particles acting as chemical catalysts.en_ES
dc.facultadFacultad de Cienciasen_ES
dc.file.nameHeinze_Wea2021.pdf
dc.identifier.citationA. N. Heinze et al 2021 ApJ 920 108en_ES
dc.identifier.doihttps://doi.org/10.3847/1538-4357/ac178b
dc.identifier.urihttp://repositoriobibliotecas.uv.cl/handle/uvscl/7368
dc.languageen
dc.publisherAmerican Astronomical Society
dc.rights© 2021. The American Astronomical Society. All rights reserved
dc.sourceThe Astrophysical Journal
dc.subjectBROWN DWARFSen_ES
dc.subjectATMOSPHERIC CLOUDSen_ES
dc.subjectEXOPLANET ATMOSPHERIC VARIABILITYen_ES
dc.subjectVARIABLE STARSen_ES
dc.subjectSPECTROPHOTOMETRYen_ES
dc.subjectTIME SERIES ANALYSISen_ES
dc.titleWeather on Other Worlds. VI. Optical Spectrophotometry of Luhman 16B Reveals Large-amplitude Variations in the Alkali Lines
dc.typeArticulo
uv.departamentoInstituto de Fisica y Astronomia

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