V. J. S. Béjar
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View article: The mass of the exo-Venus Gliese 12 b, as revealed by HARPS-N, ESPRESSO, and CARMENES
The mass of the exo-Venus Gliese 12 b, as revealed by HARPS-N, ESPRESSO, and CARMENES Open
Small temperate planets are prime targets for exoplanet studies due to their possible similarities with the rocky planets in the Solar System. M dwarfs are promising hosts since the planetary signals are within our current detection capabi…
View article: The CARMENES search for exoplanets around M dwarfs
The CARMENES search for exoplanets around M dwarfs Open
View article: A planetary system with a sub-Neptune planet in the habitable zone of TOI-2093
A planetary system with a sub-Neptune planet in the habitable zone of TOI-2093 Open
Aims . We aim to confirm and measure the mass of the transiting planet candidate around the K5 V star TOI-2093, previously announced by the Transiting Exoplanet Survey Satellite (TESS) project. Methods . We combined photometric data from 3…
View article: Euclid Quick Data Release (Q1)—Spectroscopic Search, Classification, and Analysis of Ultracool Dwarfs in the Deep Fields
Euclid Quick Data Release (Q1)—Spectroscopic Search, Classification, and Analysis of Ultracool Dwarfs in the Deep Fields Open
The Near-Infrared Spectrometer and Photometer on board the Euclid space mission has obtained near-infrared (NIR) slitless spectra of millions of objects, including hundreds of ultracool dwarfs (UCDs). Euclid observations retrieve images an…
View article: A detailed analysis of the Gl 486 planetary system
A detailed analysis of the Gl 486 planetary system Open
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…
View article: Silicate precursor silane detected in cold low-metallicity brown dwarf
Silicate precursor silane detected in cold low-metallicity brown dwarf Open
Within 20 pc of the Sun, there are currently 29 known cold brown dwarfs-sources with measured distances and an estimated effective temperature between that of Jupiter (170 K) and approximately 500 K (ref. 1). These sources are a…
View article: Polarized, variable radio emission from the scallop-shell binary system DG CVn
Polarized, variable radio emission from the scallop-shell binary system DG CVn Open
DG CVn is an eruptive variable star and represents the closest member of the known sample of complex periodic variables, or scallop-shell stars. Over the years, this M dwarf binary system has shown significant flaring activity at a wide ra…
View article: The CARMENES search for exoplanets around M dwarfs
The CARMENES search for exoplanets around M dwarfs Open
Context . Surveys for exoplanets indicate that the occurrence rate of gas giant planets orbiting late-type stars in orbits with periods shorter than 1000 days is lower than in the case of Sun-like stars. This is in agreement with planet fo…
View article: Discovery of a transiting hot water-world candidate orbiting Ross 176 with TESS and CARMENES
Discovery of a transiting hot water-world candidate orbiting Ross 176 with TESS and CARMENES Open
The Transiting Exoplanet Survey Satellite ( TESS ) discovered several new planet candidates that need to be confirmed and characterized with ground-based observations. This is the case of Ross 176, a late K-type star that hosts a promising…
View article: The mass of the exo-Venus Gliese 12 b, as revealed by HARPS-N, ESPRESSO, and CARMENES
The mass of the exo-Venus Gliese 12 b, as revealed by HARPS-N, ESPRESSO, and CARMENES Open
Small temperate planets are prime targets for exoplanet studies due to their possible similarities with the rocky planets in the Solar System. M dwarfs are promising hosts since the planetary signals are within our current detection capabi…
View article: Detection of Methane in the Closest Extreme Metal-poor T Dwarf WISEA J181006.18−101000.5*
Detection of Methane in the Closest Extreme Metal-poor T Dwarf WISEA J181006.18−101000.5* Open
WISEA J181006.18−101000.5 (WISE1810) is the nearest metal-poor ultracool dwarf to the Sun. It has a low effective temperature and has been classified as an extreme early-T subdwarf. However, methane, the characteristic molecule of the spec…
View article: Optical constraints on the coldest metal-poor population
Optical constraints on the coldest metal-poor population Open
Context. The coldest metal-poor population made up of T and Y dwarfs can serve as an archaeological tracer of our Galaxy because these very old objects have retained their pristine material. The optical properties of these objects are impo…
View article: The CARMENES search for exoplanets around M dwarfs
The CARMENES search for exoplanets around M dwarfs Open
Context. A multitude of spectral activity indicators are routinely computed nowadays from the spectra generated as part of planet-hunting radial velocity surveys. Searching for shared periods among them can help to robustly identify astrop…
View article: Coronal and chromospheric activity of Teegarden's star
Coronal and chromospheric activity of Teegarden's star Open
Teegarden's star is a late-type M-dwarf planet host, typically showing only rather low levels of activity. In this paper we present an extensive characterisation of this activity at photospheric, chromospheric, and coronal levels. We speci…
View article: The CARMENES search for exoplanets around M dwarfs
The CARMENES search for exoplanets around M dwarfs Open
Context. Current exoplanet surveys are focused on detecting small exoplanets orbiting in the liquid-water habitable zones of their host stars. Despite recent significant advancements in instrumentation, the main limitation in detecting the…
View article: Euclid Quick Data Release (Q1): A photometric search for ultracool dwarfs in the Euclid Deep Fields
Euclid Quick Data Release (Q1): A photometric search for ultracool dwarfs in the Euclid Deep Fields Open
We present a catalogue of more than 5000 new ultracool dwarf (UCD) candidates in the three Euclid Deep Fields in the Q1 data release. They range from late M to late T dwarfs, and include 1200 L and T dwarfs. More than 100 of them have been…
View article: The CARMENES search for exoplanets around M dwarfs
The CARMENES search for exoplanets around M dwarfs Open
Aims. Previous estimates of planet occurrence rates in the CARMENES survey indicated increased numbers of planets on short orbits for M dwarfs with masses below 0.34M ⊙ . Here we focused on the lowest-mass stars in the survey, comprising 1…
View article: CARMENES input catalogue of M dwarfs
CARMENES input catalogue of M dwarfs Open
Context . Multiplicity studies greatly benefit from focusing on M dwarfs because they are often paired in a variety of configurations with both stellar and substellar objects, including exoplanets. Aims . We aim to address the observed mul…
View article: Optical constraints on the coldest metal-poor population
Optical constraints on the coldest metal-poor population Open
The coldest metal-poor population made of T and Y dwarfs are archaeological tracers of our Galaxy because they are very old and have kept the pristine material. The optical properties of these objects are important to characterise their at…
View article: JWST Detects Silane in a Cold Low-Metallicity World
JWST Detects Silane in a Cold Low-Metallicity World Open
Within 20 pc of the Sun there are 29 isolated sources with measured distances (Kirkpatrick et al. 2024) and an estimated temperature between that of Jupiter (170K) and∼500K – the cold brown dwarf regime. These objects are valuable laborato…
View article: The CARMENES search for exoplanets around M dwarfs
The CARMENES search for exoplanets around M dwarfs Open
Context. Radial velocity (RV) jitter represents an intrinsic limitation on the precision of Doppler searches for exoplanets that can originate from both instrumental and astrophysical sources. Aims. We aim to determine the RV jitter floor …
View article: Hints of auroral and magnetospheric polarized radio emission from the scallop-shell star 2MASS J05082729–2101444
Hints of auroral and magnetospheric polarized radio emission from the scallop-shell star 2MASS J05082729–2101444 Open
Scallop-shell stars, a recently discovered class of young M dwarfs, show complex optical light curves that are characterized by periodic dips as well as other features that are stable over tens to hundreds of rotation cycles. The origin of…
View article: Hints of auroral and magnetospheric polarized radio emission from the scallop-shell star 2MASS J05082729$-$2101444
Hints of auroral and magnetospheric polarized radio emission from the scallop-shell star 2MASS J05082729$-$2101444 Open
Scallop-shell stars, a recently discovered class of young M dwarfs, show complex optical light curves that are characterized by periodic dips as well as other features that are stable over tens to hundreds of rotation cycles. The origin of…
View article: Coronal and chromospheric activity of Teegarden’s star
Coronal and chromospheric activity of Teegarden’s star Open
Teegarden’s star is a late-type M-dwarf planet host, typically showing only rather low levels of activity. In this paper we present an extensive characterisation of this activity at photospheric, chromospheric, and coronal levels. We speci…
View article: Validation of up to seven TESS planet candidates through multi-colour transit photometry using MuSCAT2 data
Validation of up to seven TESS planet candidates through multi-colour transit photometry using MuSCAT2 data Open
The TESS mission searches for transiting exoplanets by monitoring the brightness of hundreds of thousands of stars across the entire sky. M-type planet hosts are ideal targets for this mission due to their smaller size and cooler temperatu…
View article: The GAPS Programme at TNG
The GAPS Programme at TNG Open
Context . The long-term Global Architecture of Planetary Systems (GAPS) programme has been characterising a sample of young systems with transiting planets via spectroscopic and photometric follow-up observations. One of the main goals of …
View article: Validation of up to seven TESS planet candidates through multi-colour transit photometry using MuSCAT2 data
Validation of up to seven TESS planet candidates through multi-colour transit photometry using MuSCAT2 data Open
The TESS mission searches for transiting exoplanets by monitoring the brightness of hundreds of thousands of stars across the entire sky. M-type planet hosts are ideal targets for this mission due to their smaller size and cooler temperatu…
View article: The GAPS Programme at TNG. LIX. A characterisation study of the $\sim$300 Myr old multi-planetary system orbiting the star BD+40 2790 (TOI-2076)
The GAPS Programme at TNG. LIX. A characterisation study of the $\sim$300 Myr old multi-planetary system orbiting the star BD+40 2790 (TOI-2076) Open
We collected more than 300 high-resolution spectra of the 300 Myr old star BD+40 2790 (TOI-2076) over ~3 years. This star hosts three transiting planets discovered by TESS, with orbital periods ~10, 21, and 35 days. BD+40 2790 shows an act…
View article: <i>Euclid</i>: Early Release Observations – A glance at free-floating newborn planets in the σ Orionis cluster
<i>Euclid</i>: Early Release Observations – A glance at free-floating newborn planets in the σ Orionis cluster Open
We provide an early assessment of the imaging capabilities of the Euclid space mission to deeply probe nearby star-forming regions and associated very young open clusters, and in particular, to determine to which extent it can shed light i…
View article: Revisiting the dynamical masses of the transiting planets in the young AU Mic system: Potential AU Mic b inflation at ~20 Myr
Revisiting the dynamical masses of the transiting planets in the young AU Mic system: Potential AU Mic b inflation at ~20 Myr Open
Context . Understanding planet formation is important in the context of the origin of planetary systems in general and of the Solar System in particular, as well as to predict the likelihood of finding Jupiter, Neptune, and Earth analogues…