Our goal is to study the processes that lead to the formation of low mass stars, brown dwarfs and planets and to characterize the physical properties of these objects in various evolutionary stages. Low mass stars and brown dwarfs are likely the most numerous type of objects in our Galaxy but due to their low intrinsic luminosity they are not so well known. We aim to study the frequency, multiplicity and spatial distribution of these objects in the solar neighbourhood and in nearby star forming regions and stellar clusters in order to better understand the mechanism of formation, characterise their optical and infrared properties and establish the relation between spectral properties, mass and luminosity.. Most of our effort will be dedicated to push toward lower mass limits the detection of these astros either bounded to stars and brown dwarfs and/or free-floating in interstellar space. The lowest mass objects display a lower intrinsic luminosity and cooler effective temperatures thus they are remarkably difficult to detect using direct imaging techniques. However, these techniques allow a full photometric and spectroscopic characterization and a best determination of their physical and chemical properties. We also aim to investigate the presence of planets around low mass stars using radial velocity measurements and techniques for high spatial resolution imaging. We will develop ultrastable spectrographs for large telescopes and systems for ultrafast imaging. With the spectrographs it would be possible to detect planets of similar mass to the Earth around G, K and M-type stars. The goal is to establish the frequency of these planets in stars of the solar neighbourhood and characterise the properties of the associated planetary systems.
- The optical and near-infrared sequence of 10 Myr-old L dwarfs in the nearest OB association to the Sun, Upper Scorpius
- The lithium depletion boundary of the Hyades cluster.
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. DespiteMaas, A. J. et al.
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 forDamasso, M. et al.
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 CARMENESChaturvedi, P. et al.
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 2.23Kossakowski, D. et al.
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 reportBurdanov, Artem Y. et al.
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 thoroughlyCaballero, J. A. et al.
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 periodLuque, R. et al.
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 rotationalSchöfer, P. et al.
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 canJeffers, S. V. et al.
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 rotationQuirrenbach, A. et al.
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 initioReiners, A. et al.
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 andMurray, C. A. et al.
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 forCliment, J. B. et al.
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). HoweverPassegger, V. M. et al.
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 radiusKemmer, J. et al.
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 anGonzález-Álvarez, E. et al.
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 theseFukui, Akihiko et al.
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 linesFuhrmeister, B. et al.
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 ofSchanche, N. et al.
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
Related talksNo related talks were found.
Related conferencesNo related conferences were found.
The Euclid telescope takes off to explore the dark universeAdvertised on
An ancient brown dwarf in our cosmic neighbourhoodAdvertised on
Astronomers discover ancient brown dwarf with lithium deposits intactAdvertised on