Proyecto de Investigación: Origins 832428
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832428
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The CARMENES search for exoplanets around M dwarfs: Measuring precise radial velocities in the near infrared: The example of the super-Earth CD Cet b
(EDP Sciences, 2020-08-10) Bauer, F. F.; Zechmeister, M.; Kaminski, A.; Rodríguez López, C.; Caballero, J. A.; Azzaro, M.; Stahl, S.; Kossakowski, D.; Quirrenbach, A.; Becerril Jarque, S.; Rodríguez, E.; Amado, P. J.; Seifert, W.; Reiners, A.; Schäfer, S.; Ribas, I.; Béjar, V. J. S.; Cortés Contreras, M.; Dreizler, S.; Hatzes, A.; Henning, T.; Jeffers, S. V.; Kürster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Schmitt, H. M. M.; Schweitzer, A.; Solano, Enrique; European Research Council (ERC); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Deutsche Forschungsgemeinschaft (DFG); 0000-0003-1212-5225; 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 ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFÍSICA DE CANARIAS (IAC), SEV-2015-0548
The high-resolution, dual channel, visible and near-infrared spectrograph CARMENES offers exciting opportunities for stellar and exoplanetary research on M dwarfs. In this work we address the challenge of reaching the highest radial velocity precision possible with a complex, actively cooled, cryogenic instrument, such as the near-infrared channel. We describe the performance of the instrument and the work flow used to derive precise Doppler measurements from the spectra. The capability of both CARMENES channels to detect small exoplanets is demonstrated with the example of the nearby M5.0 V star CD Cet (GJ 1057), around which we announce a super-Earth (4.0 ± 0.4 M· ) companion on a 2.29 d orbit. © 2020 ESO.
The CARMENES search for exoplanets around M dwarfs: Characterization of the nearby ultra-compact multiplanetary system YZ Ceti
(EDP Sciences, 2020-05-01) Stock, S.; Kemmer, J.; Reffert, S.; Trifonov, T.; Kaminski, A.; Dreizler, S.; Quirrenbach, A.; Caballero, J. A.; Reiners, A.; Anglada Escudé, G.; Ribas, I.; Amado, P. J.; Barrado, D.; Barnes, J. R.; Bauer, F. F.; Berdiñas, Z. M.; Béjar, V. J. S.; Coleman, G. A. L.; Cortés Contreras, M.; Díez Alonso, E.; Domínguez Fernández, A. J.; Espinoza, N.; Haswell, C. A.; Hatzes, A.; Henning, T.; Jenkins, J. S.; Jones, H. R. A.; Kossakowski, D.; Kürster, M.; Lafarga, M.; Lee, M. H.; López González, M. J.; Montes, D.; Morales, J. C.; Morales, N.; Pallé, E.; Pedraz, S.; Rodríguez, E.; Rodríguez López, C.; Zechmeister, M.; Jeffers, S. V.; Deutsche Forschungsgemeinschaft (DFG); Agencia Estatal de Investigación (AEI); Comisión Nacional de Investigación Científica y Tecnológica (CONICYT); Ministerio de Economía y Competitividad (MINECO); Junta de Andalucía; European Research Council (ERC); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Science and Technology Facilities Council (STFC); Generalitat de Catalunya; 0000-0002-1166-9338; 0000-0003-3929-1442; 0000-0002-0460-8289; 0000-0002-0236-775X; 0000-0003-0203-8208; 0000-0002-7349-1387; 0000-0003-2490-4779; 0000-0002-6689-0312; 0000-0002-8388-6040; 0000-0003-1930-5683; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFÍSICA DE CANARIAS (IAC), SEV-2015-0548; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
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).
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.
The CARMENES search for exoplanets around M dwarfs: Dynamical characterization of the multiple planet system GJ 1148 and prospects of habitable exomoons around GJ 1148 b
(EDP Sciences, 2020-06-03) Trifonov, T.; Lee, M. H.; Kürster, M.; Henning, T.; Grishin, E.; Stock, S.; Tjoa, J.; Caballero, J. A.; Wong, K. H.; Bauer, F. F.; Quirrenbach, A.; Zechmeister, M.; Ribas, I.; Reffert, S.; Reiners, A.; Amado, P. J.; Kossakowski, D.; Azzaro, M.; Béjar, V. J. S.; Cortés Contreras, M.; Dreizler, S.; Hatzes, A. P.; Jeffers, S. V.; Kaminski, A.; Lafarga, M.; Montes, D.; Morales, J. C.; Pavlov, A.; Rodríguez López, C.; Schmitt, H. M. M.; Barnes, R.; Solano, Enrique; Deutsche Forschungsgemeinschaft (DFG); Ministerio de Economía y Competitividad (MINECO); Junta de Andalucía; European Research Council (ERC); Agencia Estatal de Investigación (AEI); Trifonov, T. https://orcid.org/0000-0002-0236-775X; 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
Context. GJ 1148 is an M-dwarf star hosting a planetary system composed of two Saturn-mass planets in eccentric orbits with periods of 41.38 and 532.02 days. Aims. We reanalyze the orbital configuration and dynamics of the GJ 1148 multi-planetary system based on new precise radial velocity measurements taken with CARMENES. Methods. We combined new and archival precise Doppler measurements from CARMENES with those available from HIRES for GJ 1148 and modeled these data with a self-consistent dynamical model. We studied the orbital dynamics of the system using the secular theory and direct N-body integrations. The prospects of potentially habitable moons around GJ 1148 b were examined. Results. The refined dynamical analyses show that the GJ 1148 system is long-term stable in a large phase-space of orbital parameters with an orbital configuration suggesting apsidal alignment, but not in any particular high-order mean-motion resonant commensurability. GJ 1148 b orbits inside the optimistic habitable zone (HZ). We find only a narrow stability region around the planet where exomoons can exist. However, in this stable region exomoons exhibit quick orbital decay due to tidal interaction with the planet. Conclusions. The GJ 1148 planetary system is a very rare M-dwarf planetary system consisting of a pair of gas giants, the inner of which resides in the HZ. We conclude that habitable exomoons around GJ 1148 b are very unlikely to exist. © 2020 T. Trifonov et al.
