Examinando por Autor "Williamson, M. H."

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Acceso Abierto
The Hubble PanCET Program: A Metal-rich Atmosphere for the Inflated Hot Jupiter HAT-P-41b
(IOP Science Publishing, 2021-01-06) Sheppard, K. B.; Welbanks, L.; Mandell, A. M.; Madhusudhan, N.; Nikolov, N.; Deming, D. L.; Henry, G. W.; Williamson, M. H.; Sing, D. K.; López Morales, M.; Ih, J.; Sanz Forcada, J.; Lavvas, P.; Ballester, G. E.; Evans, T. M.; García Muñoz, Antonio; Dos Santos, L. A.; National Aeronautics and Space Administration (NASA); Sheppard, K. B. [0000-0003-4552-9541]; Welbanks, L. [0000-0003-0156-4564]; Mandell, A. M. [0000-0002-8119-3355]; Madhusudhan, M. [0000-0002-4869-000X]; Nikolov, N. [0000-0002-6500-3574]; Deming, D. [0000-0001-5727-4094]; Sing, D. K. [0000-0001-6050-7645]; Henry, G. W. [0000-0003-4155-8513]; López Morales, M. [0000-0003-3204-8183]; Ih, J. [0000-0003-2775-653X]; Sanz Forcada, J. [0000-0002-1600-7835]; Lavvas, P. [0000-0002-5360-3660]; Evans, T. M. [0000-0001-5442-1300]; García Muñoz, A. [0000-0003-1756-4825]; Dos Santos, L. A. [0000-0002-2248-3838]
We present a comprehensive analysis of the 0.3–5 μm transit spectrum for the inflated hot Jupiter HAT-P-41b. The planet was observed in transit with Hubble STIS and WFC3 as part of the Hubble Panchromatic Comparative Exoplanet Treasury (PanCET) program, and we combine those data with warm Spitzer transit observations. We extract transit depths from each of the data sets, presenting the STIS transit spectrum (0.29–0.93 μm) for the first time. We retrieve the transit spectrum both with a free-chemistry retrieval suite (AURA) and a complementary chemical equilibrium retrieval suite (PLATON) to constrain the atmospheric properties at the day–night terminator. Both methods provide an excellent fit to the observed spectrum. Both AURA and PLATON retrieve a metal-rich atmosphere for almost all model assumptions (most likely O/H ratio of ${\mathrm{log}}_{10}Z/{Z}_{\odot }={1.46}_{-0.68}^{+0.53}$ and ${\mathrm{log}}_{10}Z/{Z}_{\odot }={2.33}_{-0.25}^{+0.23}$, respectively); this is driven by a 4.9σ detection of H2O as well as evidence of gas absorption in the optical (>2.7σ detection) due to Na, AlO, and/or VO/TiO, though no individual species is strongly detected. Both retrievals determine the transit spectrum to be consistent with a clear atmosphere, with no evidence of haze or high-altitude clouds. Interior modeling constraints on the maximum atmospheric metallicity (${\mathrm{log}}_{10}Z/{Z}_{\odot }\lt 1.7$) favor the AURA results. The inferred elemental oxygen abundance suggests that HAT-P-41b has one of the most metal-rich atmospheres of any hot Jupiters known to date. Overall, the inferred high metallicity and high inflation make HAT-P-41b an interesting test case for planet formation theories.
Acceso Abierto
The Hubble Space Telescope PanCET Program: An Optical to Infrared Transmission Spectrum of HAT-P-32Ab
(The Institute of Physics (IOP), 2020-07-02) Alam, M. K.; López Morales, M.; Nikolov, N.; Sing, D. K.; Henry, G. W.; Baxter, C.; Désert, J. M.; Barstow, J. K.; Mikal Evans, T.; Bourrier, V.; Lavvas, P.; Wakeford, H. R.; Williamson, M. H.; Sanz Forcada, J.; Buchhave, L. A.; Cohen, O.; García Muñoz, Antonio; Agencia Estatal de Investigación (AEI); National Aeronautics and Space Administration (NASA); European Research Council (ERC); Alam, M. K. [0000-0003-4157-832X]; López Morales, M. [0000-0003-3204-8183]; Nikolov, N. [0000-0002-6500-3574]; Sing, D. K. [0000-0001-6050-7645]; Henry, G. W. [0000-0003-4155-8513]; Baxter, C. [0000-0003-3438-843X]; Désert, J. M. [0000-0002-0875-8401]; Barstow, J. K. [0000-0003-3726-5419]; Mikal Evans, T. [0000-0001-5442-1300]; Bourrier, V. [0000-0002-9148-034X]; Lavvas, P. [0000-0002-5360-3660]; Wakeford, H. R. [0000-0003-4328-3867]; Forcada, J. S. [0000-0002-1600-7835]; Buchhave, L. A. [0000-0003-1605-5666]; Cohen, O. [0000-0003-3721-0215]; García Muñoz, A. [0000-0003-1756-4825]
We present a 0.3−5 μm transmission spectrum of the hot Jupiter HAT-P-32Ab observed with the Space Telescope Imaging Spectrograph and Wide Field Camera 3 instruments mounted on the Hubble Space Telescope, combined with Spitzer Infrared Array Camera photometry. The spectrum is composed of 51 spectrophotometric bins with widths ranging between 150 and 400 Å, measured to a median precision of 215 ppm. Comparisons of the observed transmission spectrum to a grid of 1D radiative-convective equilibrium models indicate the presence of clouds/hazes, consistent with previous transit observations and secondary eclipse measurements. To provide more robust constraints on the planet's atmospheric properties, we perform the first full optical to infrared retrieval analysis for this planet. The retrieved spectrum is consistent with a limb temperature of ${1248}_{-92}^{+92}$ K, a thick cloud deck, enhanced Rayleigh scattering, and ~10× solar H2O abundance. We find log(Z/Z⊙) = ${2.41}_{-0.07}^{+0.06}$, and compare this measurement with the mass–metallicity relation derived for the solar system.