Examinando por Autor "Ballester, G. E."

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Acceso Abierto
Another Servicing Mission to Extend Hubble Space Telescope’s Science past the Next Decade
(American Astronomical Society, 2019-09-30) López Morales, M.; France, K.; Ferraro, F. R.; Chandar, R.; Finkelstein, S.; Charlot, S.; Ballester, G. E.; Bersten, M. C.; Diego, J. M.; Folatelli, T.; García Senz, D.; Giavalisco, M.; Jansen, R. A.; Kelly, P. L.; Maccarone, Thomas J.; Redfield, S.; Ruiz Lapuente, P.; Shore, S.; Kallivayalil, N.; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The Hubble Space Telescope has produced astonishing science over the past thirty years. Hubble's productivity can continue to soar for years to come provided some worn out components get upgraded. While powerful new ground-based and space telescopes are expected to come online over the next decade, none of them will have the UV capabilities that make Hubble a unique observatory. Without Hubble, progress in UV and blue optical astrophysics will be halted. Observations at these wavelengths are key for a range of unresolved astrophysics questions, ranging from the characterization of solar system planets to understanding interaction of galaxies with the intergalactic medium and the formation history of the universe. Hubble will remain our only source of high-angular resolution UV imaging and high-sensitivity UV spectroscopy for the next two decades, offering the ability for continued unique science and maximizing the science return from complementary observatories. Therefore, we recommend that NASA, ESA, and the private sector study the scientific merit, technical feasibility, and risk of a new servicing mission to Hubble to boost its orbit, fix aging components, and expand its instrumentation. Doing so would: 1) keep Hubble on its path to reach its unmet full potential, 2) extend the mission's lifetime past the next decade, which will maximize the synergy of Hubble with other upcoming facilities, and 3) enable and enhance the continuation of scientific discoveries in UV and optical astrophysics.
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
WASP-52b. The effect of star-spot correction on atmospheric retrievals
(Oxford Academics: Oxford University Press, 2019-11-18) Bruno, G.; Lewis, N. K.; Alam, M. K.; López Morales, M.; Barstow, J. K.; Wakeford, H. R.; Sing, D. K.; Henry, G. W.; Ballester, G. E.; Bourrier, V.; Buchhave, L. A.; Cohen, O.; Mikal Evans, T.; García Muñoz, Antonio; Lavvas, P.; Sanz Forcada, J.; Agencia Estatal de Investigación (AEI); National Aeronautics and Space Administration (NASA); European Research Council (ERC); Deutsche Forschungsgemeinschaft (DFG); Buchhave, L. A. [0000-0003-1605-5666]; Bruno, G. [0000-0002-3288-0802]; Sing, D. [0000-0001-6050-7645]; Mikal Evans, T. [0000-0001-5442-1300]; Alam, M. [0000-0003-4157-832X]; Wakeford, H. [0000-0003-4328-3867]
We perform atmospheric retrievals on the full optical to infrared (⁠0.3−5μm⁠) transmission spectrum of the inflated hot Jupiter WASP-52b by combining HST/STIS, WFC3 IR, and Spitzer/IRAC observations. As WASP-52 is an active star that shows both out-of-transit photometric variability and star-spot crossings during transits, we account for the contribution of non-occulted active regions in the retrieval. We recover a 0.1–10× solar atmospheric composition, in agreement with core accretion predictions for giant planets, and no significant contribution of aerosols. We also obtain a <3000 K temperature for the star-spots, a measure which is likely affected by the models used to fit instrumental effects in the transits, and a 5 per cent star-spot fractional coverage, compatible with expectations for the host star’s spectral type. Such constraints on the planetary atmosphere and on the activity of its host star will inform future JWST GTO observations of this target.