Characterization of the atmosphere of the hot Jupiter HAT-P-32Ab and the M-dwarf companion HAT-P-32B
Files
Accepted manuscript
Date
2014-12-01
Authors
Zhao, Ming
O'Rourke, Joseph G.
Wright, Jason T.
Knutson, Heather A.
Burrows, Adam
Fortney, Johnathan
Ngo, Henry
Fulton, Benjamin J.
Baranec, Christoph
Riddle, Reed
Version
Accepted manuscript
OA Version
Citation
Ming Zhao, Joseph G O'Rourke, Jason T Wright, Heather A Knutson, Adam Burrows, Johnathan Fortney, Henry Ngo, Benjamin J Fulton, Christoph Baranec, Reed Riddle, Nicholas M Law, Philip S Muirhead, Sasha Hinkley, Adam P Showman, Jason Curtis, Rick Burruss. 2014. "CHARACTERIZATION OF THE ATMOSPHERE OF THE HOT JUPITER HAT-P-32Ab AND THE M-DWARF COMPANION HAT-P-32B." ASTROPHYSICAL JOURNAL, Volume 796, Issue 2, 15 pp. https://doi.org/10.1088/0004-637X/796/2/115
Abstract
We report secondary eclipse photometry of the hot Jupiter HAT-P-32Ab, taken with Hale/WIRC
in H and KS bands and with Spitzer/IRAC at 3.6 and 4.5 μm. We carried out adaptive optics
imaging of the planet host star HAT-P-32A and its companion HAT-P-32B in the near-IR and the
visible. We clearly resolve the two stars from each other and find a separation of 2.′′923 ± 0.′′004 and
a position angle 110.◦64 ± 0.◦12. We measure the flux ratios of the binary in g′r′i′z′ and H & KS
bands, and determine Teff = 3565 ± 82 K for the companion star, corresponding to an M1.5 dwarf.
We use PHOENIX stellar atmosphere models to correct the dilution of the secondary eclipse depths
of the hot Jupiter due to the presence of the M1.5 companion. We also improve the secondary eclipse
photometry by accounting for the non-classical, flux-dependent nonlinearity of the WIRC IR detector
in the H band. We measure planet-to-star flux ratios of 0.090 ± 0.033%, 0.178 ± 0.057%, 0.364 ±
0.016%, and 0.438 ± 0.020% in the H, KS, 3.6 and 4.5 μm bands, respectively. We compare these
with planetary atmospheric models, and find they prefer an atmosphere with a temperature inversion
and inefficient heat redistribution. However, we also find that the data are equally well-described by
a blackbody model for the planet with Tp = 2042 ± 50 K. Finally, we measure a secondary eclipse
timing offset of 0.3 ± 1.3 min from the predicted mid-eclipse time, which constrains e = 0.0072+0.0700
−0.0064 when combined with RV data and is more consistent with a circular orbit.