Cloud Atlas: High-precision HST/WFC3/IR Time-Resolved Observations of Directly-Imaged Exoplanet HD106906b. (arXiv:2001.08304v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_Y/0/1/0/all/0/1">Yifan Zhou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Apai_D/0/1/0/all/0/1">D&#xe1;niel Apai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bedin_L/0/1/0/all/0/1">Luigi R. Bedin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lew_B/0/1/0/all/0/1">Ben W. P. Lew</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schneider_G/0/1/0/all/0/1">Glenn Schneider</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burgasser_A/0/1/0/all/0/1">Adam J. Burgasser</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Manjavacas_E/0/1/0/all/0/1">Elena Manjavacas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Karalidi_T/0/1/0/all/0/1">Theodora Karalidi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Metchev_S/0/1/0/all/0/1">Stanimir Metchev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miles_Paez_P/0/1/0/all/0/1">Paulo A. Miles-P&#xe1;ez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cowan_N/0/1/0/all/0/1">Nicolas B. Cowan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lowrance_P/0/1/0/all/0/1">Patrick J. Lowrance</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Radigan_J/0/1/0/all/0/1">Jacqueline Radigan</a>

HD106906b is an ~11$M_{mathrm{Jup}}$, ~15Myr old directly-imaged exoplanet
orbiting at an extremely large distance from its host star. The wide separation
(7.11 arcsec) between HD106906b 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. In this paper, we
present HST/WFC3/IR time-resolved observations of HD106906b in the F127M,
F139M, and F153M bands. We have achieved ~1% precision in the lightcurves in
all three bands. The F127M lightcurve demonstrates marginally-detectable
($2.7sigma$ significance) variability with a best-fitting period of 4 hr,
while the lightcurves in the other two bands are consistent with flat lines. We
construct primary-subtracted deep images and use these images to exclude
additional companions to HD106906 that are more massive than
4$M_{mathrm{Jup}}$ and locate at projected distances of more than ~500 au. We
measure the astrometry of HD106906b in two HST/WFC3 epochs and achieve
precisions better than 2.5 mas. The position angle and separation measurements
do not deviate from those in the 2004 HST/ACS/HRC images for more than
$1sigma$ uncertainty. We provide the HST/WFC3 astrometric results for 25
background stars that can be used as reference sources in future precision
astrometry studies. Our observations also provide the first 1.4-micron water
band photometric measurement for HD106906b. HD106906b’s spectral energy
distribution and the best-fitting BT-Settl model have an inconsistency in the
1.4-micron water absorption band, which highlights the challenges in modeling
atmospheres of young planetary-mass objects.

HD106906b is an ~11$M_{mathrm{Jup}}$, ~15Myr old directly-imaged exoplanet
orbiting at an extremely large distance from its host star. The wide separation
(7.11 arcsec) between HD106906b 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. In this paper, we
present HST/WFC3/IR time-resolved observations of HD106906b in the F127M,
F139M, and F153M bands. We have achieved ~1% precision in the lightcurves in
all three bands. The F127M lightcurve demonstrates marginally-detectable
($2.7sigma$ significance) variability with a best-fitting period of 4 hr,
while the lightcurves in the other two bands are consistent with flat lines. We
construct primary-subtracted deep images and use these images to exclude
additional companions to HD106906 that are more massive than
4$M_{mathrm{Jup}}$ and locate at projected distances of more than ~500 au. We
measure the astrometry of HD106906b in two HST/WFC3 epochs and achieve
precisions better than 2.5 mas. The position angle and separation measurements
do not deviate from those in the 2004 HST/ACS/HRC images for more than
$1sigma$ uncertainty. We provide the HST/WFC3 astrometric results for 25
background stars that can be used as reference sources in future precision
astrometry studies. Our observations also provide the first 1.4-micron water
band photometric measurement for HD106906b. HD106906b’s spectral energy
distribution and the best-fitting BT-Settl model have an inconsistency in the
1.4-micron water absorption band, which highlights the challenges in modeling
atmospheres of young planetary-mass objects.

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