Examinando por Autor "Herrero, E."

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A nearby transiting rocky exoplanet that is suitable for atmospheric investigation
(Science, 2021-03-05) Trifonov, T.; Caballero, J. A.; Morales, J. C.; Seifahrt, A.; Reiners, A.; Bean, J. L.; Luque, R.; Parviainen, H.; Pallé, E.; Stock, S.; Zechmeister, M.; Amado, P. J.; Anglada Escudé, G.; Azzaro, M.; Barclay, T.; Béjar, V. J. S.; Bluhm, P.; Casasayas Barris, N.; Cifuentes, C.; Collins, K. A.; Collins, K. I.; Cortés Contreras, M.; De Leon, J. P.; Dreizler, S.; Dressing, C. D.; Esparza Borges, E.; Espinoza, N.; Fausnaugh, M.; Fukui, A.; Hatzes, A. P.; Hellier, C.; Henning, T.; Henze, C. E.; Herrero, E.; Jeffers, S. V.; Jenkins, J. M.; Jensen, E. L. N.; Kaminski, A.; Kasper, D.; Kossakowski, D.; Kürster, M.; Lafarga, M.; Latham, D. W.; Mann, A. W.; Molaverdikhani, K.; Montes, D.; Montet, B. T.; Murgas Alcaino, F.; Narita, N.; Oshagh, M.; Passegger, V. M.; Pollacco, D.; Quinn, S. N.; Quirrenbach, A.; Ricker, G. R.; Rodríguez López, C.; Sánz Forcada, J.; Schwarz, R. P.; Schweitzer, A.; Seager, S.; Shporer, A.; Stangret, M.; Stürmer, J.; Tan, T. G.; Tenenbaum, P.; Twicken, J. D.; Vanderspek, R.; Winn, J. N.; Deutsche Forschungsgemeinschaft (DFG); Agencia Estatal de Investigación (AEI); National Aeronautics and Space Administration (NASA); European Research Council (ERC); Japan Society for the Promotion of Science (JSPS); La Caixa; Japan Science and Technology Agency (JST); Trifonov, T. [0000-0002-0236-775X]; Caballero, J. A. [0000-0002-7349-1387]; Morales, J. C. [0000-0003-0061-518X]; Seifahrt, A. [0000-0003-4526-3747]; Ribas, I. [0000-0002-6689-0312]; Bean, J. [0000-0003-4733-6532]; Luque, R. [0000-0002-4671-2957]; Parviainen, H. [0000-0001-5519-1391]; Pallé, E. [0000-0003-0987-1593]; Stock, S. [0000-0002-1166-9338]; Zechmeister, M. [0000-0002-6532-4378]; Amado, P. J. [0000-0002-8388-6040]; Anglada Escudé, G. [0000-0002-3645-5977]; Azzaro, M. [0000-0002-1317-0661]; Barclay, T. [0000-0001-7139-2724]; Béjar, V. J. S. [0000-0002-5086-4232]; Bluhm, P. [0000-0002-0374-8466]; Casasayas Barris, N. [0000-0002-2891-8222]; Cifuentes, C. [0000-0003-1715-5087]; Collins, K. A. [0000-0001-6588-9574]; Collins, K. I. [0000-0003-2781-3207]; Cortés Contreras, M. [0000-0003-3734-9866]; Dreizler, S. [0000-0001-6187-5941]; Dressing, C. D. [0000-0001-8189-0233]; Esparza Borges, E. [0000-0002-2341-3233]; Espinoza, N. [0000-0001-9513-1449]; Fausnaugh, M. [0000-0002-9113-7162]; Fukui, A. [0000-0002-4909-5763]; Hatzes, A. P. [0000-0002-3404-8358]; Hellier, C. [0000-0002-3439-1439]; Henning, T. [0000-0002-1493-300X]; Herrero, E. [0000-0001-8602-6639]; Jeffers, S. V. [0000-0003-2490-4779]; Jenkins, J. M. [0000-0002-4715-9460]; Jensen, E. L. N. [0000-0002-4625-7333]; Kaminski, A. [0000-0003-0203-8208]; Kasper, D. [0000-0003-0534-6388]; Kossakowski, D. [0000-0002-0436-7833]; Lafarga, M. [0000-0002-8815-9416]; Latham, D. W. [0000-0001-9911-7388]; Mann, A. W. [0000-0003-3654-1602]; Molaverdikhani, K. [0000-0002-0502-0428]; Montes, D. [0000-0002-7779-238X]; Montet, B. T. [0000-0001-7516-8308]; Murgas, F. [0000-0001-9087-1245]; Narita, N. [0000-0001-8511-2981]; Oshagh, M. [0000-0002-0715-8789]; Passegger, V. M. [0000-0002-8569-7243]; Pollacco, D. [0000-0001-9850-9697]; Quinn, S. N. [0000-0002-8964-8377]; Rodríguez López, C. [0000-0001-5559-7850]; Sanz Forcada, J. [0000-0002-1600-7835]; Schwarz, R. P. [0000-0001-8227-1020]; Schweitzer, A. [0000-0002-1624-0389]; Seager, S. [0000-0002-6892-6948]; Stangret, M. [0000-0002-1812-8024]; Stürmer, J. [0000-0002-4410-4712]; Tan, T. G. [0000-0001-5603-6895]; Tenenbaum, P. [0000-0002-1949-4720]; Twicken, J. D. [0000-0002-6778-7552]; Vanderspek, R. [0000-0001-6763-6562]; Winn, J. N. [0000-0002-4265-047X]; 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
Spectroscopy of transiting exoplanets can be used to investigate their atmospheric properties and habitability. Combining radial velocity (RV) and transit data provides additional information on exoplanet physical properties. We detect a transiting rocky planet with an orbital period of 1.467 days around the nearby red dwarf star Gliese 486. The planet Gliese 486 b is 2.81 Earth masses and 1.31 Earth radii, with uncertainties of 5%, as determined from RV data and photometric light curves. The host star is at a distance of ~8.1 parsecs, has a J-band magnitude of ~7.2, and is observable from both hemispheres of Earth. On the basis of these properties and the planet’s short orbital period and high equilibrium temperature, we show that this terrestrial planet is suitable for emission and transit spectroscopy.
Acceso Abierto
The CARMENES search for exoplanets around M dwarfs Convective shift and starspot constraints from chromatic radial velocities
(EDP Sciences, 2020-09-10) Baroch, D.; Morales, J. C.; Ribas, I.; Herrero, E.; Rosich, A.; Perger, M.; Anglada Escudé, G.; Reiners, A.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Jeffers, S. V.; Cifuentes, C.; Passegger, V. M.; Schweitzer, A.; Lafarga, M.; Bauer, F. F.; Béjar, V. J. S.; Colomé, J.; Cortés Contreras, M.; Dreizler, S.; Galadí Enríquez, D.; Hatzes, A. P.; Henning, T.; Kaminski, A.; Kürster, M.; Montes, D.; Rodríguez López, C.; Zechmeister, M.; Deutsche Forschungsgemeinschaft (DFG); Agencia Estatal de Investigación (AEI); National Aeronautics and Space Administration (NASA); Baroch, D. [0000-0001-7568-5161]; Ribas, I. [0000-0002-6689-0312]; Montes, D. [0000-0002-7779-238X]; 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. Variability caused by stellar activity represents a challenge to the discovery and characterization of terrestrial exoplanets and complicates the interpretation of atmospheric planetary signals. Aims. We aim to use a detailed modeling tool to reproduce the effect of active regions on radial velocity measurements, which aids the identification of the key parameters that have an impact on the induced variability. Methods. We analyzed the effect of stellar activity on radial velocities as a function of wavelength by simulating the impact of the properties of spots, shifts induced by convective motions, and rotation. We focused our modeling effort on the active star YZ CMi (GJ 285), which was photometrically and spectroscopically monitored with CARMENES and the Telescopi Joan Oró. Results. We demonstrate that radial velocity curves at different wavelengths yield determinations of key properties of active regions, including spot-filling factor, temperature contrast, and location, thus solving the degeneracy between them. Most notably, our model is also sensitive to convective motions. Results indicate a reduced convective shift for M dwarfs when compared to solar-type stars (in agreement with theoretical extrapolations) and points to a small global convective redshift instead of blueshift. Conclusions. Using a novel approach based on simultaneous chromatic radial velocities and light curves, we can set strong constraints on stellar activity, including an elusive parameter such as the net convective motion effect.
Acceso Abierto
The CARMENES search for exoplanets around M dwarfs Three temperate-to-warm super-Earths
(EDP Sciences, 2020-11-10) Stock, S.; Nagel, E.; Kemmer, J.; Passegger, V. M.; Reffert, S.; Quirrenbach, A.; Caballero, J. A.; Czesla, S.; Béjar, V. J. S.; Cardona Guillén, C.; Díez Alonso, E.; Herrero, E.; Lalitha, S.; Schlecker, M.; Tal Or, L.; Rodríguez, E.; Rodríguez López, C.; Ribas, I.; Reiners, A.; Amado, P. J.; Bauer, F. F.; Bluhm, P.; Cortés Contreras, M.; González Cuesta, L.; Dreizler, S.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; López González, M. J.; Montes, D.; Morales, J. C.; Pedraz, S.; Schöfer, P.; Schweitzer, A.; Trifonov, T.; Zapatero Osorio, M. R.; Zechmeister, M.; Agencia Estatal de Investigación (AEI); Generalitat de Catalunya; National Aeronautics and Space Administration (NASA); Tel-Aviv University (Israel); Stock, S. [0000-0002-1166-9338]; Nagel, E. [0000-0002-4019-3631]; Kemmer, J. [0000-0003-3929-1442]; Reffert, S. [0000-0002-0460-8289]; Caballero, J. A. [0000-0002-7349-1387]; Cardona, C. [0000-0002-2198-4200]; Schlecker, M. [0000-0001-8355-2107]; Tal Or, L. [0000-0003-3757-1440]; Rodríguez, E. [0000-0001-6827-9077]; Ribas, I. [0000-0002-6689-0312]; Amado, P. J. [0000-0002-8388-6040]; Cortés Contreras, M. [0000-0003-3734-9866]; González Cuesta, L. [0000-0002-1241-5508]; López González, M. J. [0000-0001-8104-5128]; Zapatero Osorio, M. R. [0000-0001-5664-2852]; Zechmeister, M. [0000-0002-6532-4378]; 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
We announce the discovery of two planets orbiting the M dwarfs GJ 251 (0.360 ± 0.015M⊙) and HD 238090 (0.578 ± 0.021M⊙) based on CARMENES radial velocity (RV) data. In addition, we independently confirm with CARMENES data the existence of Lalande 21185 b, a planet that has recently been discovered with the SOPHIE spectrograph. All three planets belong to the class of warm or temperate super-Earths and share similar properties. The orbital periods are 14.24 d, 13.67 d, and 12.95 d and the minimum masses are 4.0 ± 0.4 M⊕, 6.9 ± 0.9 M⊕, and 2.7 ± 0.3 M⊕ for GJ 251 b, HD 238090 b, and Lalande 21185 b, respectively. Based on the orbital and stellar properties, we estimate equilibrium temperatures of 351.0 ± 1.4 K for GJ 251 b, 469.6 ± 2.6 K for HD 238090 b, and 370.1 ± 6.8 K for Lalande 21185 b. For the latter we resolve the daily aliases that were present in the SOPHIE data and that hindered an unambiguous determination of the orbital period. We find no significant signals in any of our spectral activity indicators at the planetary periods. The RV observations were accompanied by contemporaneous photometric observations. We derive stellar rotation periods of 122.1 ± 2.2 d and 96.7 ± 3.7 d for GJ 251 and HD 238090, respectively. The RV data of all three stars exhibit significant signals at the rotational period or its first harmonic. For GJ 251 and Lalande 21185, we also find long-period signals around 600 d, and 2900 d, respectively, which we tentatively attribute to long-term magnetic cycles. We apply a Bayesian approach to carefully model the Keplerian signals simultaneously with the stellar activity using Gaussian process regression models and extensively search for additional significant planetary signals hidden behind the stellar activity. Current planet formation theories suggest that the three systems represent a common architecture, consistent with formation following the core accretion paradigm.
Acceso Abierto
The CARMENES search for exoplanets around M dwarfs: Radial velocities and activity indicators from cross-correlation functions with weighted binary masks
(EDP Sciences, 2020-04-13) Lafarga, M.; Ribas, I.; Lovis, C.; Perger, M.; Zechmeister, M.; Bauer, F.; Kürster, M.; Cortés Contreras, M.; Morales, J. C.; Herrero, E.; Rosich, A.; Baroch, D.; Reiners, A.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Alacid, J. M.; Béjar, V. J. S.; Dreizler, S.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Montes, D.; Pedraz, S.; Rodríguez López, C.; Schmitt, H. M. M.; 0000-0002-8815-9416; 0000-0002-6532-4378; 0000-0002-7349-1387; 0000-0001-9224-0455; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. For years, the standard procedure to measure radial velocities (RVs) of spectral observations consisted in cross-correlating the spectra with a binary mask, that is, a simple stellar template that contains information on the position and strength of stellar absorption lines. The cross-correlation function (CCF) profiles also provide several indicators of stellar activity. Aims. We present a methodology to first build weighted binary masks and, second, to compute the CCF of spectral observations with these masks from which we derive radial velocities and activity indicators. These methods are implemented in a python code that is publicly available. Methods. To build the masks, we selected a large number of sharp absorption lines based on the profile of the minima present in high signal-to-noise ratio (S/N) spectrum templates built from observations of reference stars. We computed the CCFs of observed spectra and derived RVs and the following three standard activity indicators: full-width-at-half-maximum as well as contrast and bisector inverse slope. Results. We applied our methodology to CARMENES high-resolution spectra and obtain RV and activity indicator time series of more than 300 M dwarf stars observed for the main CARMENES survey. Compared with the standard CARMENES template matching pipeline, in general we obtain more precise RVs in the cases where the template used in the standard pipeline did not have enough S/N. We also show the behaviour of the three activity indicators for the active star YZ CMi and estimate the absolute RV of the M dwarfs analysed using the CCF RVs. © ESO 2020.