A5008397678- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
Spanish National Observatory
2019-2024
Universidad Complutense de Madrid
2019
Instituto Geográfico Nacional
2019
Context. Teegarden's Star is the brightest and one of nearest ultra-cool dwarfs in solar neighbourhood. For its late spectral type (M7.0V), star shows relatively little activity a prime target for near-infrared radial velocity surveys such as CARMENES. Aims. As part CARMENES search exoplanets around M dwarfs, we obtained more than 200 radial-velocity measurements analysed them planetary signals. Methods. We find periodic variability velocities Star. also studied photometric to rule out...
Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB) when an efficient mass-loss process removes a significant fraction of their initial mass. For most sources, this relies on interplay between convection, stellar pulsations, dust formation. However, predicting history given star from first principles is complex not yet feasible at present. At end AGB, least some experience substantial increase in rate for unknown reasons, leading to creation post-AGB objects...
Statistical analyses from exoplanet surveys around low-mass stars indicate that super-Earth and Neptune-mass planets are more frequent than gas giants such stars, in agreement with core accretion theory of planet formation. Using precise radial velocities derived visual near-infrared spectra, we report the discovery a giant minimum mass 0.46 Jupiter masses an eccentric 204-day orbit very star GJ 3512. Dynamical models show high eccentricity is most likely explained planet-planet...
Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB), when an efficient mass-loss process removes a significant fraction of their initial mass. A substantial increase in rate at end AGB is observed for least some unknown reasons. This creates post-AGB objects that are completely enshrouded thick dusty envelopes might be associated with binary interactions. We $J=2-1$ line $^{13}$CO, C$^{17}$O, C$^{18}$O Atacama Large Millimeter / submillimeter Array (ALMA)...
There is a class of binary post-AGB stars with remarkable near-infrared excess that are surrounded by Keplerian or quasi-Keplerian disks and extended outflows composed gas escaping from the disk. The dynamics had been well identified in four cases, namely Red Rectangle, AC Her, IW Car, IRAS 08544-4431. In these objects, mass outflow represents ~ 10 % nebular mass, disk being dominant component nebula. We present interferometric NOEMA maps 12CO 13CO J=2-1 89 Her 19125+0343, R Sct. Several...
There is a class of binary post-asymptotic giant branch (post-AGB) stars that exhibit remarkable near-infrared (NIR) excess. These are surrounded by disks with Keplerian or quasi-Keplerian dynamics and outflows composed gas escaping from the rotating disk. Depending on dominance these components, there two subclasses post-AGB stars: disk-dominated outflow-dominated. We aim to properly study hourglass-like structure surrounds disk around 89 Her. present total-power on-the-fly maps $^{12}$CO...
Context. There is a class of binary post-asymptotic giant branch (post-AGB) stars that exhibit remarkable near-infrared (NIR) excess. Such are surrounded by Keplerian or quasi-Keplerian disks, as well extended outflows composed gas escaping from the disk. This can be subdivided into disk- and outflow-dominated sources, depending on whether it disk outflow represents most nebular mass, respectively. The chemistry this type source has been practically unknown thus far. Methods. We focused our...
Stellar evolution models serve as tools to derive stellar parameters from elemental and isotopic abundance ratios. For low-to-intermediate mass evolved stars, C/O, 12C/13C, 17O/18O ratios are proxies of the initial mass, a largely unknown parameter in post-AGB sources, yet fundamental establish correlations with main properties their envelopes, progressing understanding formation evolution. In these C/O ratio can be constrained detection C- or O-bearing species addition CO, while is...
There is a class of binary post-AGB stars that are surrounded by Keplerian disks and often present outflows resulting from gas escaping the disk. We maps complex models 12CO 13CO J=2-1 emission lines for four objects: AC Herculis, 89 IRAS 19125+0343, R Scuti. Our allow us to study their morphology, kinematics, mass distribution. modeling Her reveal 95% total nebular located in So this source disk-dominated (like Red Rectangle, IW Carinae, 08544-4431). On contrary, our Scuti suggest outflow...
There is a class of binary post-asymptotic giant branch (post-AGB) stars that exhibit remarkable near-infrared (NIR) excess. These are surrounded by disks with Keplerian or quasi-Keplerian dynamics and outflows composed gas escaping from the rotating disk. Depending on dominance these components, there two subclasses post-AGB stars: disk-dominated outflow-dominated. We aim to properly study hourglass-like structure surrounds disk around 89 Her. present total-power on-the-fly maps $^{12}$CO...
There is a class of binary post-AGB stars (binary system including star) that are surrounded by Keplerian disks and outflows resulting from gas escaping the disk. To date, there seven sources have been studied in detail through interferometric millimeter-wave maps CO lines (ALMA/NOEMA). For cases Red Rectangle, IW Carinae, IRAS 08544-4431, AC Herculis, it found around ≥85% total nebular mass located disk with dynamics. The remainder an expanding component. This outflow probably wind...
There is a class of binary post-AGB stars (binary system including star) that are surrounded by Keplerian disks and outflows resulting from gas escaping the disk. To date, there seven sources have been studied in detail through interferometric millimeter-wave maps CO lines (ALMA/NOEMA). For cases Red Rectangle, IW Carinae, IRAS 08544-4431, AC Herculis, it found around greater than 85% total nebular mass located disk with dynamics. The remainder an expanding component. This outflow probably...