Subvenciones relacionadas:
General
Se investigan los procesos que conducen a la formación de estrellas de baja masa, enanas marrones y exoplanetas y caracterizar las propiedades físicas de estos astros en varias etapas evolutivas. Las estrellas de muy baja masa y las enanas marrones son probablemente los objetos más numerosos de nuestra Galaxia, pero no por ello están suficientemente bien establecidas sus propiedades. En particular, los objetos subestelares constituyen uno de los grupos más difíciles de estudiar desde el punto de vista observacional dada su baja luminosidad intrínseca. Se pretende establecer la frecuencia, multiplicidad y distribución espacial de estrellas ultrafrías y objetos subestelares en la vecindad del Sol y en regiones de formación estelar y cúmulos cercanos con el fin de proporcionar información sobre los mecanismos que los originan, caracterizar sus propiedades ópticas e infrarrojas, y establecer relaciones entre sus propiedades espectrales, masas y luminosidades. Se hace especial énfasis en empujar la frontera de detección hacia los objetos de menor masa, bien sea como objetos ligados por atracción gravitatoria a otros, o flotando libremente en el espacio interestelar. Los objetos menos masivos también suelen ser los de menor luminosidad intrínseca y temperaturas superficiales más frías por lo que entrañan notable dificultad de detección por medio de imagen directa. Sin embargo, la detección directa permite una caracterización fotométrica y espectroscópica mucho más completa y una mejor determinación de sus propiedades físicas y químicas. También se pretende investigar la presencia de exoplanetas en estrellas de baja masa empleando técnicas de medida de velocidad radial con muy alta precisión y técnicas de muy alta resolución espacial. Se trabaja en el desarrollo de espectrógrafos ultraestables para grandes telescopios y de sistemas de imagen ultrarrápida. Con los primeros es posible lograr la detección de planetas con masas similares a la de la Tierra en estrellas de tipos G, K y M un objetivo que se persigue es establecer la frecuencia de estos planetas en las estrellas de la vecindad solar y caracterizar las propiedades de los sistemas planetarios a los que pertenecen.
Miembros
Resultados
- La secuencia visible y infrarroja de las enanas de tipo L de 10 Myr de edad en la asociación OB mas cercana al Sol, Upper Scorpius
- El limite estelar/subestelar del cumulo más cercano al Sol, las Hiades
Actividad científica
Publicaciones relacionadas
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Lower-than-expected flare temperatures for TRAPPIST-1
Aims: Stellar flares emit thermal and nonthermal radiation in the X-ray and ultraviolet (UV) regime. Although high energetic radiation from flares is a potential threat to exoplanet atmospheres and may lead to surface sterilization, it might also provide the extra energy for low-mass stars needed to trigger and sustain prebiotic chemistry. Despite
Maas, A. J. et al.Fecha de publicación:
122022 -
A quarter century of spectroscopic monitoring of the nearby M dwarf Gl 514. A super-Earth on an eccentric orbit moving in and out of the habitable zone
Context. Statistical analyses based on Kepler data show that most of the early-type M dwarfs host multi-planet systems consisting of Earth- to sub-Neptune-sized planets with orbital periods of up to ~250 days, and that at least one such planet is likely located within the habitable zone. M dwarfs are therefore primary targets to search for
Damasso, M. et al.Fecha de publicación:
102022 -
TOI-1468: A system of two transiting planets, a super-Earth and a mini-Neptune, on opposite sides of the radius valley
We report the discovery and characterization of two small transiting planets orbiting the bright M3.0V star TOI-1468 (LSPM J0106+1913), whose transit signals were detected in the photometric time series in three sectors of the TESS mission. We confirm the planetary nature of both of them using precise radial velocity measurements from the CARMENES
Chaturvedi, P. et al.Fecha de publicación:
102022 -
The CARMENES search for exoplanets around M dwarfs. Stable radial-velocity variations at the rotation period of AD Leonis: A test case study of current limitations to treating stellar activity
Context. A challenge with radial-velocity (RV) data is disentangling the origin of signals either due to a planetary companion or to stellar activity. In fact, the existence of a planetary companion has been proposed, as well as contested, around the relatively bright, nearby M3.0 V star AD Leo at the same period as the stellar rotation of 2.23
Kossakowski, D. et al.Fecha de publicación:
102022 -
SPECULOOS Northern Observatory: Searching for Red Worlds in the Northern Skies
SPECULOOS is a ground-based transit survey consisting of six identical 1 m robotic telescopes. The immediate goal of the project is to detect temperate terrestrial planets transiting nearby ultracool dwarfs (late M-dwarf stars and brown dwarfs), which could be amenable for atmospheric research with the next generation of telescopes. Here, we report
Burdanov, Artem Y. et al.Fecha de publicación:
102022 -
A detailed analysis of the Gl 486 planetary system
Context. The Gl 486 system consists of a very nearby, relatively bright, weakly active M3.5 V star at just 8 pc with a warm transiting rocky planet of about 1.3 R⊕ and 3.0 M⊕. It is ideal for both transmission and emission spectroscopy and for testing interior models of telluric planets. Aims: To prepare for future studies, we aim to thoroughly
Caballero, J. A. et al.Fecha de publicación:
92022 -
The HD 260655 system: Two rocky worlds transiting a bright M dwarf at 10 pc
We report the discovery of a multiplanetary system transiting the M0 V dwarf HD 260655 (GJ 239, TOI-4599). The system consists of at least two transiting planets, namely HD 260655 b, with a period of 2.77 d, a radius of Rb = 1.240 ± 0.023 R⊕, a mass of Mb = 2.14 ± 0.34 M⊕, and a bulk density of ρb = 6.2 ± 1.0 g cm−3, and HD 260655 c, with a period
Luque, R. et al.Fecha de publicación:
82022 -
The CARMENES search for exoplanets around M dwarfs. Rotational variation in activity indicators of Ross 318, YZ CMi, TYC 3529-1437-1, and EV Lac
Context. The Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Échelle Spectrographs (CARMENES) instrument is searching for periodic radial-velocity (RV) variations of M dwarfs, which are induced by orbiting planets. However, there are other potential sources of such variations, including rotational
Schöfer, P. et al.Fecha de publicación:
72022 -
The CARMENES search for exoplanets around M dwarfs. Benchmarking the impact of activity in high-precision radial velocity measurements
Context. Current exoplanet surveys using the radial velocity (RV) technique are targeting M dwarfs because any habitable zone terrestrial-mass planets will induce a high RV and orbit on shorter periods than for more massive stars. One of the main caveats is that M dwarfs show a wide range of activity levels from inactive to very active, which can
Jeffers, S. V. et al.Fecha de publicación:
72022 -
The CARMENES search for exoplanets around M dwarfs. Two Saturn-mass planets orbiting active stars
The CARMENES radial-velocity survey is currently searching for planets in a sample of 387 M dwarfs. Here we report on two Saturn-mass planets orbiting TYC 2187-512-1 (M* = 0.50 M⊙) and TZ Ari (M* = 0.15 M⊙), respectively. We obtained supplementary photometric time series, which we use along with spectroscopic information to determine the rotation
Quirrenbach, A. et al.Fecha de publicación:
72022 -
Magnetism, rotation, and nonthermal emission in cool stars. Average magnetic field measurements in 292 M dwarfs
Stellar dynamos generate magnetic fields that are of fundamental importance to the variability and evolution of Sun-like and low-mass stars, and for the development of their planetary systems. As a key to understanding stellar dynamos, empirical relations between stellar parameters and magnetic fields are required for comparison to ab initio
Reiners, A. et al.Fecha de publicación:
62022 -
A study of flares in the ultra-cool regime from SPECULOOS-South
We present a study of photometric flares on 154 low-mass (≤0.2 M⊙) objects observed by the SPECULOOS-South Observatory from 2018 June 1 to 2020 March 23. In this sample, we identify 85 flaring objects, ranging in spectral type from M4 to L0. We detect 234 flares in this sample, with energies between 1029.2 and 1032.7 erg, using both automated and
Murray, C. A. et al.Fecha de publicación:
62022 -
Radio emission in a nearby, ultra-cool dwarf binary: A multifrequency study
Context. The substellar triple system VHS J125601.92−125723.9 (hereafter VHS 1256−1257) is composed of an equal-mass M7.5 brown dwarf binary and an L7 low-mass substellar object. In Guirado et al. (2018, A&A, 610, A23) we published the detection of radio emission at 8.4 GHz coming from the central binary and making it an excellent target for
Climent, J. B. et al.Fecha de publicación:
42022 -
Metallicities in M dwarfs: Investigating different determination techniques
Deriving metallicities for solar-like stars follows well-established methods, but for cooler stars such as M dwarfs, the determination is much more complicated due to forests of molecular lines that are present. Several methods have been developed in recent years to determine accurate stellar parameters for these cool stars (Teff ≲ 4000 K). However
Passegger, V. M. et al.Fecha de publicación:
22022 -
Discovery and mass measurement of the hot, transiting, Earth-sized planet, GJ 3929 b
We report the discovery of GJ 3929 b, a hot Earth-sized planet orbiting the nearby M3.5 V dwarf star, GJ 3929 (G 180-18, TOI-2013). Joint modelling of photometric observations from TESS sectors 24 and 25 together with 73 spectroscopic observations from CARMENES and follow-up transit observations from SAINT-EX, LCOGT, and OSN yields a planet radius
Kemmer, J. et al.Fecha de publicación:
32022 -
A multi-planetary system orbiting the early-M dwarf TOI-1238
Context. The number of super-Earth and Earth-mass planet discoveries has increased significantly in the last two decades thanks to the Doppler radial velocity and planetary transit observing techniques. Either technique can detect planet candidates on its own, but the power of a combined photometric and spectroscopic analysis is unique for an
González-Álvarez, E. et al.Fecha de publicación:
22022 -
TOI-2285b: A 1.7 Earth-radius planet near the habitable zone around a nearby M dwarf
We report the discovery of TOI-2285b, a sub-Neptune-sized planet transiting a nearby (42 pc) M dwarf with a period of 27.3 d. We identified the transit signal from the Transiting Exoplanet Survey Satellite photometric data, which we confirmed with ground-based photometric observations using the multiband imagers MuSCAT2 and MuSCAT3. Combining these
Fukui, Akihiko et al.Fecha de publicación:
22022 -
The CARMENES search for exoplanets around M dwarfs. Diagnostic capabilities of strong K I lines for photosphere and chromosphere
There are several strong K I lines found in the spectra of M dwarfs, among them the doublet near 7700 Å and another doublet near 12 500 Å. We study these optical and near-infrared doublets in a sample of 324 M dwarfs, observed with CARMENES, the high-resolution optical and near-infrared spectrograph at Calar Alto, and investigate how well the lines
Fuhrmeister, B. et al.Fecha de publicación:
12022 -
TOI-2257 b: A highly eccentric long-period sub-Neptune transiting a nearby M dwarf
Context. Thanks to the relative ease of finding and characterizing small planets around M-dwarf stars, these objects have become cornerstones in the field of exoplanet studies. The current paucity of planets in long-period orbits around M dwarfs makes such objects particularly compelling as they provide clues about the formation and evolution of
Schanche, N. et al.Fecha de publicación:
12022 -
TOI-2285b: A 1.7 Earth-radius planet near the habitable zone around a nearby M dwarf
We report the discovery of TOI-2285b, a sub-Neptune-sized planet transiting a nearby (42 pc) M dwarf with a period of 27.3 d. We identified the transit signal from the Transiting Exoplanet Survey Satellite photometric data, which we confirmed with ground-based photometric observations using the multiband imagers MuSCAT2 and MuSCAT3. Combining these
Fecha de publicación:
122021Bibcode
