Cloud Atlas: High-precision HST/WFC3/IR Time-resolved Observations of Directly Imaged Exoplanet HD 106906b

摘要: HD 106906b is an ~11M_(Jup), ~15 Myr old directly imaged exoplanet orbiting at extremely large distance from its host star. The wide separation (7 11) between and star greatly reduces the difficulty in direct-imaging observations, making it one of most favorable exoplanets for detailed characterization. In this paper, we present HST/WFC3/IR time-resolved observations F127M, F139M, F153M bands. We have achieved ~1% precision lightcurves all three F127M lightcurve demonstrates marginally detectable (2.7σ significance) variability with a best-fitting period 4 hr, while other two bands are consistent flat lines. construct primary-subtracted deep images use these to exclude additional companions 106906 that more massive than M_(Jup) locate projected distances ~500 au. measure astrometry HST/WFC3 epochs achieve precisions better 2.5 mas. position angle measurements do not deviate those 2004 HST/ACS/HRC 1σ uncertainty. provide astrometric results 25 background stars can be used as reference sources future studies. Our also first 1.4 μm water band photometric measurement 106906b. 106906b's spectral energy distribution BT-Settl model inconsistency absorption band, which highlights challenges modeling atmospheres young planetary-mass objects.