Examinando por Autor "Salz, M."

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Acceso Abierto
Evidence of energy-, recombination-, and photon-limited escape regimes in giant planet H/He atmospheres
(EDP Sciences, 2021-04-23) Lampón, M.; López Puertas, M.; Czesla, S.; Sánchez López, A.; Lara, L. M.; Salz, M.; Sanz Forcada, J.; Molaverdikhani, K.; Quirrenbach, A.; Pallé, E.; Caballero, J. A.; Henning, T.; Nortmann, L.; Amado, P. J.; Montes, D.; Reiners, A.; Ribas, I.; Consejo Superior de Investigaciones Científicas (CSIC); Junta de Andalucía; European Regional Development Fund (ERDF); Deutsche Forschungsgemeinschaft (DFG); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Generalitat de Catalunya; European Research Council (ERC); Lampón, M. [0000-0002-0183-7158]; López Puertas, M. [0000-0003-2941-7734]; Sánchez López, A. [0000-0002-0516-7956]; Lara, L. M. [0000-0002-7184-920X]; Sanz Forcada, J. [0000-0002-1600-7835]; Molaverdikhani, K. [0000-0002-0502-0428]; Caballero, J. A. [0000-0002-7349-1387]; Nortmann, L. [0000-0001-8419-8760]; Amado, P. J. [0000-0001-8012-3788]; Montes, D. [0000-0002-7779-238X]; Ribas, I. [0000-0002-6689-0312]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737; Centro de Excelencia Científica Severo Ochoa Instituto de Astrofísica de Andalucía , SEV-2017-0709; Centro de Excelencia Científica Severo Ochoa Instituto de Astrofísica de Canarias, SEV-2015-0548
Hydrodynamic escape is the most efficient atmospheric mechanism of planetary mass loss and has a large impact on planetary evolution. Three hydrodynamic escape regimes have been identified theoretically: energy-limited, recombination-limited, and photon-limited. However, no evidence of these regimes had been reported until now. Here, we report evidence of these three regimes via an analysis of a helium I triplet at 10 830 Å and Lyα absorption involving a 1D hydrodynamic model that allows us to estimate hydrogen recombination and advection rates. In particular, we show that HD 209458 b is in the energy-limited regime, HD 189733 b is in the recombination-limited regime, and GJ 3470 b is in the photon-limited regime. These exoplanets can be considered as benchmark cases for their respective regimes.
Acceso Abierto
Modelling the He I triplet absorption at 10 830 Å in the atmospheres of HD 189733 b and GJ 3470 b
(EDP Sciences, 2021-03-23) Lampón, M.; López Puertas, M.; Sanz Forcada, J.; Sánchez López, A.; Molaverdikhani, K.; Czesla, S.; Quirrenbach, A.; Pallé, E.; Caballero, J. A.; Henning, T.; Salz, M.; Nortmann, L.; Aceituno, J.; Amado, P. J.; Bauer, F. F.; Montes, D.; Nagel, E.; Reiners, A.; Ribas, I.; European Regional Development Fund (ERDF); Deutsche Forschungsgemeinschaft (DFG); Agencia Estatal de Investigación (AEI); Generalitat de Catalunya; European Research Council (ERC); 0000-0002-0183-7158; 0000-0003-2941-7734; 0000-0002-1600-7835; 0000-0002-0516-7956; 0000-0002-7349-1387; 0000-0001-8419-8760; 0000-0001-8012-3788; 0000-0002-4019-3631; 0000-0002-6689-0312; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFÍSICA DE CANARIAS (IAC), SEV-2015-0548; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709
Characterising the atmospheres of exoplanets is key to understanding their nature and provides hints about their formation and evolution. High resolution measurements of the helium triplet absorption of highly irradiated planets have been recently reported, which provide a new means of studying their atmospheric escape. In this work we study the escape of the upper atmospheres of HD 189733 b and GJ 3470 b by analysing high resolution He I triplet absorption measurements and using a 1D hydrodynamic spherically symmetric model coupled with a non-local thermodynamic model for the He I triplet state. We also use the H density derived from Lyα observations to further constrain their temperatures, mass-loss rates, and H/He ratios. We have significantly improved our knowledge of the upper atmospheres of these planets. While HD 189733 b has a rather compressed atmosphere and small gas radial velocities, GJ 3470 b, on the other hand with a gravitational potential ten times smaller, exhibits a very extended atmosphere and large radial outflow velocities. Hence, although GJ 3470 b is much less irradiated in the X-ray and extreme ultraviolet radiation, and its upper atmosphere is much cooler, it evaporates at a comparable rate. In particular, we find that the upper atmosphere of HD 189733 b is compact and hot, with a maximum temperature of 12 400−300+400 K, with a very low mean molecular mass (H/He = (99.2/0.8) ± 0.1), which is almost fully ionised above 1.1 RP, and with a mass-loss rate of (1.1 ± 0.1) × 1011 g s−1. In contrast, the upper atmosphere of GJ 3470 b is highly extended and relatively cold, with a maximum temperature of 5100 ± 900 K, also with a very low mean molecular mass (H/He = (98.5/1.5)−1.5+1.0), which is not strongly ionised, and with a mass-loss rate of (1.9 ± 1.1) × 1011 g s−1. Furthermore, our results suggest that upper atmospheres of giant planets undergoing hydrodynamic escape tend to have a very low mean molecular mass (H/He ≳ 97/3).
Acceso Abierto
Multiple water band detections in the CARMENES near-infrared transmission spectrum of HD 189733 b
(EDP Sciences, 2019-01-10) Alonso Floriano, F. J.; Sánchez López, A.; Snellen, I. A. G.; López Puertas, M.; Nagel, E.; Amado, P. J.; Bauer, F. F.; Caballero, J. A.; Czesla, S.; Nortmann, L.; Pallé, E.; Salz, M.; Reiners, A.; Ribas, I.; Quirrenbach, A.; Aceituno, J.; Anglada Escudé, G.; Béjar, V. J. S.; Guenther, E. W.; Henning, T.; Kaminski, A.; Kürster, M.; Lampón, M.; Lara, L. M.; Montes, D.; Morales, J. C.; Tal Or, L.; Schmitt, J. H. M. M.; Zapatero Osorio, M. R.; Zechmeister, M.; European Research Council (ERC); Ministerio de Economía y Competitividad (MINECO); Ministerio de Ciencia e Innovación (MICINN); Agencia Estatal de Investigación (AEI); Zapatero Osorio, M. R. [0000-0001-5664-2852]; Ribas, I. [0000-0002-6689-0312]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Aims. We explore the capabilities of CARMENES for characterising hot-Jupiter atmospheres by targeting multiple water bands, in particular, those at 1.15 and 1.4 μm. Hubble Space Telescope observations suggest that this wavelength region is relevant for distinguishing between hazy and/or cloudy and clear atmospheres. Methods. We observed one transit of the hot Jupiter HD 189733 b with CARMENES. Telluric and stellar absorption lines were removed using SYSREM, which performs a principal component analysis including proper error propagation. The residual spectra were analysed for water absorption with cross-correlation techniques using synthetic atmospheric absorption models. Results. We report a cross-correlation peak at a signal-to-noise ratio (S/N) of 6.6, revealing the presence of water in the transmission spectrum of HD 189733 b. The absorption signal appeared slightly blueshifted at –3.9 ± 1.3 km s−1. We measured the individual cross-correlation signals of the water bands at 1.15 and 1.4 μm, finding cross-correlation peaks at S/N of 4.9 and 4.4, respectively. The 1.4 μm feature is consistent with that observed with the Hubble Space Telescope. Conclusions. The water bands studied in this work have been mainly observed in a handful of planets from space. Being able also to detect them individually from the ground at higher spectral resolution can provide insightful information to constrain the properties of exoplanet atmospheres. Although the current multi-band detections can not yet constrain atmospheric haze models for HD 189733 b, future observations at higher S/N could provide an alternative way to achieve this aim.