A5014634369- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Astronomical and nuclear sciences
- Geography and Environmental Studies in Latin America
- Mediterranean and Iberian flora and fauna
- Historical Studies on Spain
- High-pressure geophysics and materials
- Science, Technology, and Education in Latin America
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Historical Art and Architecture Studies
- Higher Education in Latin America
- Geography and Education Methods
- Space Exploration and Technology
Universidad Nacional de Córdoba
2019-2024
Consejo Nacional de Investigaciones Científicas y Técnicas
2016-2024
Argentine National Observatory
2005-2024
National Observatory
2007-2016
Centro Científico Tecnológico - Córdoba
2016
Centro Científico Tecnológico - San Juan
2014
Valongo Observatory
2007-2012
Drake University
2010
Instituto de Astrofísica de Canarias
2007
Aims. Exo-planets are preferentially found around high metallicity main sequence stars. We investigate whether evolved stars share this property, and its implications for planet formation.
We present fundamental stellar parameters and chemical abundances for a sample of 86 evolved stars with planets control 137 without planets. The analysis was based on both high S/N resolution echelle spectra. goals this work are i) to investigate differences between planets; ii) explore potential the properties around giants subgiants; iii) search possible correlations these their host stars. In agreement previous studies, we find that subgiants are, average, more metal-rich than by ~ 0.16...
We obtained spectra, covering the CaII H and K region, for 49 exoplanet host (EH) stars, observable from southern hemisphere. measured chromospheric activity index, . compiled previously published values of this index observed objects as well remaining EH stars in an effort to better smooth temporal variations derive a more representative value average each object. used obtain ages group stars. In addition we applied other methods, such as: Isochrone, lithium abundance, metallicity...
In this paper we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy a sample 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities scale height, radial velocities, the Na, Al, $alpha$-elements, iron-peak elements, s-process elements Y, Zr, La, Ce, Nd. employed local-thermodynamic-equilibrium model atmospheres Kurucz spectral code {\sc moog}. found that metallicities,...
We determined the atmospheric parameters and abundance pattern for a sample of metal-rich barium stars. used high-resolution optical spectroscopy. Atmospheric abundances were using local thermodynamic equilibrium atmosphere models Kurucz spectral analysis code MOOG. show that stars have enhancement factors, [s/Fe], from 0.25 to 1.16. Their Na, Al, alpha-elements, iron group elements as well their kinematical properties are similar characteristics other super already analyzed. conclude do not...
The relative distribution of abundances refractory, intermediate, and volatile elements in stars with planets can be an important tool for investigating the internal migration a giant planet. This lead to accretion planetesimals selective enrichment star these elements. We report on spectroscopic determination atmospheric parameters chemical parent transiting CoRoT-2b CoRoT-4b. Adding data CoRoT-3 CoRoT-5 from literature, we find flat as function their condensation temperatures. For CoRoT-2,...
Gravitational redshifts in solar-type main-sequence stars are expected to be some 500 ms$^{-1}$ greater than those giants. Such a signature is searched for between groups of open-cluster which share the same average space motion and thus have Doppler shift. 144 cool giants were observed M67 open cluster using ESO FEROS spectrograph, obtaining radial velocities by cross correlation with spectral template. dwarf giant radial-velocity distributions well represented Gaussian functions, sharing...
High-velocity halo stars provide important information about the properties of extreme Galactic halo. The study unbound and bound Population II permits us to better estimate mass halo.} {We carried out a detailed spectroscopic kinematic have significantly refined distance evolutionary state star. Its atmospheric parameters, chemical abundances kinematical were determined using high-resolution optical spectroscopy employing local-thermodynamic-equilibrium model atmospheres Kurucz spectral...
We investigate two topics regarding solar mass FGK-type stars, the lithium rotation connection (LRC) and existence of "lithium desert". determine minimum critical velocity ($v \sin i$) related with LRC separating slow from rapid stellar rotators, as being 5 km s$^{-1}$. This value also split different properties. For first time we explore behaviour for some associations ages between 45 Myr 120 Myr. allows us to study age dependence at beginning general spin down stage low which starts $\sim$...
Dwarf stars with debris discs and planets appear to be excellent laboratories study the core accretion theory of formation. These systems are however, insufficiently studied. In this paper we present main metallicity lithium abundance properties these together only planets. Stars without detected nor also considered. The analysed sample is formed by main-sequence FGK field single stars. Apart from basic stellar parameters, include use dusty masses. results show for first time that dust mass...
We present UBRVI polarimetry measurements for a group of 38 IRAS infrared excess stars and complement these observations with V-band data taken from the literature 87 additional objects. After correcting observed values by interstellar contribution, we find that 48% analyzed sample has polarization excess. In addition, may correlate color excesses, particularly at 60 100 μm. caution, however, poor quality longer wavelengths affects this correlation. analyze wavelength dependence linear 15...
The nature of the few known solar-mass stars simultaneously containing debris disks and planets remains an open question. A number works have shown that this property appears to be independent planetary masses as well stellar age, but possible correlations with kinematics metallicity not been investigated. In paper, we show majority both belong metal-enriched Galactic thin disk. exceptions are seem born in star formation peak occurring times thick disk (i.e., HD 10700, 20794, 40307), is,...
The lithium abundance, A(Li), in stellar atmospheres suffers from various enhancement and depletion processes during the star's lifetime. While several studies have demonstrated that these are linked to physics of formation evolution, role Galactic-scale events play galactic A(Li) evolution is not yet well understood. We aim demonstrate observed bi-modal distribution, particular FGK-dwarf population, a statistical artefact two populations connect through region with low number stars. also...
This work aims to investigate the behaviour of lithium abundance in stars with and without detected planets. Our study is based on a sample 1332 FGK main-sequence measured abundances, for 257 which planets were detected. method reviews statistics addressed specifically influence tides orbital decay, special attention close orbits, whose stellar rotational velocity higher than period planet. In this case, tidal effects are much more pronounced. The analysis also covers decay short timescale,...
This work aims to investigate the behaviour of lithium abundance in stars with and without detected planets. Our study is based on a sample 1332 FGK main-sequence measured abundances, for 257 which planets were detected. method reviews statistics addressed specifically influence tides orbital decay, special attention close orbits, whose stellar rotational velocity higher than period planet. In this case, tidal effects are much more pronounced. The analysis also covers decay short timescale,...
The photospheres of stars hosting planets have larger metallicity than lacking planets. In the present work we study possibility an earlier metal enrichment by means impacting planetesimals during first 20-30Myr. Here explore this contamination process simulating interactions inward migrating planet with a disc planetesimal interior to its orbit. results show percentage that fall on star. We identified dependence planet's eccentricity ($e_p$) and time scale migration ($τ$) rate infalling...
Abstract Using a collection of 40 debris disks (DD) around dwarf A-type stars (from which 17 are spatially resolved) having well determined stellar ages (Vican 2012), we found that for collisional self-stirring model flux distributions (Kenyon & Bromley, 2008, 2010) dusty DD occupy large part the terminal age positions corresponding end MS phase. This situation does not necessarily mean dust generation in these is finished at this stage. Dusty can continue their lives next Post-MS...