TY - JOUR
T1 - Maps of evolving cloud structures in luhman 16AB from hst time-resolved spectroscopy
AU - Karalidi, Theodora
AU - Apai, Dániel
AU - Marley, Mark S.
AU - Buenzli, Esther
N1 - Funding Information:
This work is part of the Spitzer Cycle-9 Exploration Program Extrasolar Storms (program No. 90063). Support for this work was provided by NASA through an award issued by JPL/Caltech. Support for Program number 12314 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. An allocation of computer time from the UA Research Computing High Performance Computing (HTC) and High Throughput Computing (HTC) at the University of Arizona is gratefully acknowledged. This study, in part, is based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 526555. D. Apai acknowledges support by the National Aeronautics and Space Administration under agreement No. NNX15AD94G for the program Earths in Other Solar Systems. We thank I.J.M. Crossfield for providing us with the previously published Luhman 16B map data set. We thank Ben W.P.Lew for providing us with a best-fit exoplanet period for the PPCS-1 in Luhman 16B light curves. We thank the anonymous referee for a helpful report.
Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved.
PY - 2016/7/10
Y1 - 2016/7/10
N2 - WISE J104915.57-531906.1 is the nearest brown dwarf binary to our solar system, consisting of two brown dwarfs in the L/T transition: Luhman 16A and B. In this paper, we present the first map of Luhman 16A, and maps of Luhman 16B for two epochs. Our maps were created by applying Aeolus, a Markov-Chain Monte Carlo code that maps the top-of-the-atmosphere (TOA) structure of brown dwarf and other ultracool atmospheres, to light curves of Luhman 16A and B using the Hubble Space Telescope's G141 and G102 grisms. Aeolus retrieved three or four spots in the TOA of Luhman 16A and B, with a surface coverage of 19%-32% (depending on an assumed rotational period of 5 hr or 8 hr) or 21%-38.5% (depending on the observational epoch), respectively. The brightness temperature of the spots of the best-fit models was ∼200 K hotter than the background TOA. We compared our Luhman 16B map with the only previously published map. Interestingly, our map contained a large TOA spot that was cooler (ΔT ∼ 51 K) than the background, which lay at low latitudes, in agreement with the previous Luhman 16B map. Finally, we report the detection of a feature reappearing in Luhman 16B light curves that are separated by tens of hundreds of rotations from each other. We speculate that this feature is related to TOA structures of Luhman 16B.
AB - WISE J104915.57-531906.1 is the nearest brown dwarf binary to our solar system, consisting of two brown dwarfs in the L/T transition: Luhman 16A and B. In this paper, we present the first map of Luhman 16A, and maps of Luhman 16B for two epochs. Our maps were created by applying Aeolus, a Markov-Chain Monte Carlo code that maps the top-of-the-atmosphere (TOA) structure of brown dwarf and other ultracool atmospheres, to light curves of Luhman 16A and B using the Hubble Space Telescope's G141 and G102 grisms. Aeolus retrieved three or four spots in the TOA of Luhman 16A and B, with a surface coverage of 19%-32% (depending on an assumed rotational period of 5 hr or 8 hr) or 21%-38.5% (depending on the observational epoch), respectively. The brightness temperature of the spots of the best-fit models was ∼200 K hotter than the background TOA. We compared our Luhman 16B map with the only previously published map. Interestingly, our map contained a large TOA spot that was cooler (ΔT ∼ 51 K) than the background, which lay at low latitudes, in agreement with the previous Luhman 16B map. Finally, we report the detection of a feature reappearing in Luhman 16B light curves that are separated by tens of hundreds of rotations from each other. We speculate that this feature is related to TOA structures of Luhman 16B.
KW - methods: statistical
KW - stars: individual (WISE J104915.57-531906.1)
KW - techniques: photometric
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U2 - 10.3847/0004-637X/825/2/90
DO - 10.3847/0004-637X/825/2/90
M3 - Article
AN - SCOPUS:84978483961
SN - 0004-637X
VL - 825
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 90
ER -