Proyecto de Investigación: ESP2017-87676-C5-5-R
Cargando...
Colaboradores
Financiadores
ID
ESP2017-87676-C5-5-R
Autores
Publicaciones
A super-Earth on a close-in orbit around the M1V star GJ 740 A HADES and CARMENES collaboration
(EDP Sciences, 2021-04-07) Toledo Padrón, B.; Suárez Mascareño, A.; González Hernández, J. I.; Rebolo, R.; Pinamonti, M.; Perger, M.; Scandariato, G.; Damasso, M.; Sozzetti, A.; Moldonado, J.; Desidera, S.; Ribas, I.; Micela, G.; Affer, L.; González Álvarez, E.; Leto, G.; Pagano, I.; Zanmar Sánchez, R.; Giacobbe, P.; Herrero, Enrique; Morales, J. C.; Amado, P. J.; Caballero, J. A.; Quirrenbach, A.; Reiners, A.; Zechmeister, M.; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Generalitat de Catalunya
Context. M-dwarfs have proven to be ideal targets for planetary radial velocity (RV) searches due to their higher planet-star mass contrast, which favors the detection of low-mass planets. The abundance of super-Earth and Earth-like planets detected around this type of star motivates further such research on hosts without reported planetary companions.
Aims. The HADES and CARMENES programs are aimed at carrying out extensive searches of exoplanetary systems around M-type stars in the northern hemisphere, allowing us to address, in a statistical sense, the properties of the planets orbiting these objects. In this work, we perform a spectroscopic and photometric study of one of the program stars (GJ 740), which exhibits a short-period RV signal that is compatible with a planetary companion.
Methods. We carried out a spectroscopic analysis based on 129 HARPS-N spectra taken over a time span of 6 yr combined with 57 HARPS spectra taken over 4 yr, as well as 32 CARMENES spectra taken during more than 1 yr, resulting in a dataset with a time coverage of 10 yr. We also relied on 459 measurements from the public ASAS survey with a time-coverage of 8 yr, along with 5 yr of photometric magnitudes from the EXORAP project taken in the V, B, R, and I filters to carry out a photometric study. Both analyses were made using Markov chain Monte Carlo simulations and Gaussian process regression to model the activity of the star.
Results. We present the discovery of a short-period super-Earth with an orbital period of 2.37756−0.00011+0.00013 d and a minimum mass of 2.96−0.48+0.50 M⊕. We offer an update to the previously reported characterization of the magnetic cycle and rotation period of the star, obtaining values of Prot = 35.563 ± 0.071 d and Pcycle = 2800 ± 150 d. Furthermore, the RV time series exhibits a possibly periodic long-term signal, which might be related to a Saturn-mass planet of ~100 M⊕.
The CARMENES search for exoplanets around M dwarfs: LP 714-47 b (TOI 442.01): populating the Neptune desert
(EDP Sciences, 2020-12-11) Dreizler, S.; Crossfield, J. M.; Kossakowski, D.; Plavchan, P.; Jeffers, S. V.; Kemmer, J.; Luque, R.; Espinoza, N.; Pallé, E.; Stassun, K.; Matthews, E.; Chontos, A.; Esparza Borges, E.; Evans, P.; Ciardi, D. R.; Flowers, E. E.; Fukui, A.; Collins, K. I.; Furlan, E.; Gaidos, E.; Crane, J. D.; Giacalone, S.; Gillon, M.; Dragomir, D.; Gorjian, V.; Hellier, C.; Feng, F.; Howard, A. W.; Howell, Steve B.; Fulton, B.; Isaacson, I.; Geneser, C.; Jensen, E. L. N.; Kaminski, A.; Gonzales, E.; Kawauchi, K.; Kielkopf, J. F.; Hidalgo, D.; Kosiarek, M. R.; Kreidberg, L.; Huber, D.; Lafarga, M.; Livingston, J.; Jehin, E.; Mann, A. W.; Madrigal Aguado, A.; Kane, S. R.; Mocnik, T.; Morales, J. C.; Klahr, H.; Murgas Alcaino, F.; Kürster, M.; Narita, N.; Nowak, G.; Louie, D.; Parviainen, H.; Passegger, V. M.; Matson, R. A.; Pozuelos, F. J.; Quirrenbach, A.; Muirhead, P. S.; Ribas, I.; Robertson, P.; Nandakumar, S.; Rose, M. E.; Roy, A.; Oshagh, M.; Schlieder, Joshua; Shectman, S.; Pollacco, D.; Senavci, H. V.; Reefe, M.; Twicken, J. D.; Villaseñor, J. N.; Rodríguez López, C.; Weiss, L. M.; Wittrock, J.; Schweitzer, A.; Zohrabi, F.; Cale, B.; Tanner, A.; Schlecker, M.; Lillo Box, J.; Teske, J.; Lalitha, S.; Reiners, A.; Wang, S. X.; Bitsch, B.; Zapatero Osorio, M. R.; Yilmaz, M.; Ricker, George; Caballero, J. A.; Latham, D. W.; Seager, S.; Zechmeister, M.; Jenkins, J. M.; Aceituno, J.; Soubkiou, A.; Barkaoui, K.; Chaturvedi, P.; Hatzes, Artie; Batalha, N. M.; Bauer, F. F.; Vanderspek, R.; Benkhaldoun, Z.; Beichman, C.; Winn, J. N.; Butler, R. P.; Caldwell, D. A.; Amado, P. J.; Christianesen, J. L.; Barbieri, M.; Cifuentes, C.; Collins, K. A.; Benneke, B.; Combs, D.; Cortés Contreras, M.; Burt, J.; Daylan, T.; Chintada, A.; Junta de Andalucia; National Aeronautics and Space Administration (NASA); European Research Council (ERC); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Generalitat de Catalunya; Science and Technology Facilities Council (STFC); Centre National de la Recherche Scientifique (CNRS); Japan Society for the Promotion of Science (KAKENHI); 0000-0001-6187-5941; 0000-0002-8864-1667; 0000-0003-3929-1442; 0000-0003-0987-1593; 0000-0002-7349-1387; 0000-0003-3742-1987; 0000-0002-8388-6040; 0000-0003-1715-5087; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We report the discovery of a Neptune-like planet (LP 714-47 b, P = 4.05204 d, m(b) = 30.8 +/- 1.5M(circle plus), R-b = 4.7 +/- 0.3 R-circle plus) located in the "hot Neptune desert". Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer, and ground-based photometry from MuSCAT2, TRAPPIST-South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TuBTAK National Observatory, the University of Louisville Manner Telescope, and WASP-South. We also present high-spatial resolution adaptive optics imaging with the Gemini Near-Infrared Imager. The low uncertainties in the mass and radius determination place LP 714-47 b among physically well-characterised planets, allowing for a meaningful comparison with planet structure models. The host star LP 714-47 is a slowly rotating early M dwarf (T-eff = 3950 +/- 51 K) with a mass of 0.59 +/- 0.02M(circle dot) and a radius of 0.58 +/- 0.02R(circle dot). From long-term photometric monitoring and spectroscopic activity indicators, we determine a stellar rotation period of about 33 d. The stellar activity is also manifested as correlated noise in the radial-velocity data. In the power spectrum of the radial-velocity data, we detect a second signal with a period of 16 days in addition to the four-day signal of the planet. This could be shown to be a harmonic of the stellar rotation period or the signal of a second planet. It may be possible to tell the difference once more TESS data and radial-velocity data are obtained.
Unveiling the power spectra of delta Scuti stars with TESS The temperature, gravity, and frequency scaling relation
(EDP Sciences, 2020-06-11) Barceló Forteza, S.; Moya, A.; Barrado, D.; Solano, Enrique; Martín Ruiz, S.; Suárez, J. C.; García Hernández, A.; National Aeronautics and Space Administration (NASA); Ministerio de Economía y Competitividad (MINECO); European Research Council (ERC); Agencia Estatal de Investigación (AEI); Universidad de Granada (UGR); Junta de Andalucía; 0000-0001-9281-2919; 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
Thanks to high-precision photometric data legacy from space telescopes like CoRoT andKepler, the scientific community could detect and characterize the power spectra of hundreds of thousands of stars. Using the scaling relations, it is possible to estimate masses and radii for solar-type pulsators. However, these stars are not the only kind of stellar objects that follow these rules:delta Scuti stars seem to be characterized with seismic indexes such as the large separation (Delta nu). Thanks to long-duration high-cadence TESS light curves, we analysed more than two thousand of this kind of classical pulsators. In that way, we propose the frequency at maximum power (nu(max)) as a proper seismic index since it is directly related with the intrinsic temperature, mass and radius of the star. This parameter seems not to be affected by rotation, inclination, extinction or resonances, with the exception of the evolution of the stellar parameters. Furthermore, we can constrain rotation and inclination using the departure of temperature produced by the gravity-darkening effect. This is especially feasible for fast rotators as most of delta Scuti stars seem to be. © ESO 2020.
Gliese 49: activity evolution and detection of a super-Earth A HADES and CARMENES collaboration
(EDP Sciences, 2019-04-24) Perger, M.; Scandariato, G.; Ribas, I.; Morales, J. C.; Affer, L.; Azzaro, M.; Amado, P. J.; Anglada Escudé, G.; Baroch, D.; Barrado, D.; Bauer, F. F.; Béjar, V. J. S.; Caballero, J. A.; Cortés Contreras, M.; Damasso, M.; Dreizler, S.; González Cuesta, L.; González Hernández, J. I.; Guenther, E. W.; Henning, T.; Herrero, Enrique; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Leto, G.; López González, M. J.; Maldonado, J.; Micela, G.; Montes, D.; Pinamonti, M.; Quirrenbach, A.; Rebolo, R.; Reiners, A.; Rodríguez, E.; Rodríguez López, C.; Schimitt, J. H. M. M.; Sozzetti, A.; Suárez Mascareño, A.; Toledo Padrón, B.; Zanmar Sánchez, R.; Zapatero Osorio, M. R.; Zechmeister, M.; Ministerio de Economía y Competitividad (MINECO); European Commission (EC); Agencia Estatal de Investigación (AEI); 0000-0001-7098-0372; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. Small planets around low-mass stars often show orbital periods in a range that corresponds to the temperate zones of their host stars which are therefore of prime interest for planet searches. Surface phenomena such as spots and faculae create periodic signals in radial velocities and in observational activity tracers in the same range, so they can mimic or hide true planetary signals.
Aims. We aim to detect Doppler signals corresponding to planetary companions, determine their most probable orbital configurations, and understand the stellar activity and its impact on different datasets.
Methods. We analyzed 22 yr of data of the M1.5 V-type star Gl 49 (BD+61 195) including HARPS-N and CARMENES spectrographs, complemented by APT2 and SNO photometry. Activity indices are calculated from the observed spectra, and all datasets are analyzed with periodograms and noise models. We investigated how the variation of stellar activity imprints on our datasets. We further tested the origin of the signals and investigate phase shifts between the different sets. To search for the best-fit model we maximize the likelihood function in a Markov chain Monte Carlo approach.
Results. As a result of this study, we are able to detect the super-Earth Gl 49b with a minimum mass of 5.6 M⊕. It orbits its host star with a period of 13.85 d at a semi-major axis of 0.090 au and we calculate an equilibrium temperature of 350 K and a transit probability of 2.0%. The contribution from the spot-dominated host star to the different datasets is complex, and includes signals from the stellar rotation at 18.86 d, evolutionary timescales of activity phenomena at 40–80 d, and a long-term variation of at least four years.
