![]() HD 106906b’s spectral energy distribution and the best-fitting BT-Settl model have an inconsistency in the 1.4 μm water absorption band, which highlights the challenges in modeling atmospheres of young planetary-mass objects. Our observations also provide the first 1.4 μm water band photometric measurement for HD 106906b. We provide the HST/WFC3 astrometric results for 25 background stars that can be used as reference sources in future precision astrometry studies. The position angle and separation measurements do not deviate from those in the 2004 HST/ACS/HRC images for more than 1 σ uncertainty. In the second paper of this series, we perfected our method of linking high-precision Hubble Space Telescope astrometry to the high-accuracy Gaia DR2. We measure the astrometry of HD 106906b in two HST/WFC3 epochs and achieve precisions better than 2.5 mas. We construct primary-subtracted deep images and use these images to exclude additional companions to HD 106906 that are more massive than 4 M J u p and locate at projected distances of more than ∼500 au. The F127M lightcurve demonstrates marginally detectable (2.7 σ significance) variability with a best-fitting period of 4 hr, while the lightcurves in the other two bands are consistent with flat lines. Absolute astrometry, on the other hand, is more difficult owing to uncertainties in the locations of the instrument apertures relative to the Optical Telescope Assembly (OTA) and inherent uncertainty in the guide star positions. We have achieved ∼1% precision in the lightcurves in all three bands. Differential astrometry is easy and relatively accurate for HST images. In this paper, we present HST/WFC3/IR time-resolved observations of HD 106906b in the F127M, F139M, and F153M bands. The wide separation (7.″11) between HD 106906b and its host star greatly reduces the difficulty in direct-imaging observations, making it one of the most favorable directly imaged exoplanets for detailed characterization. ![]() HD 106906b is an ∼ 11 M J u p, ∼15 Myr old directly imaged exoplanet orbiting at an extremely large distance from its host star.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |