arXiv subjects

E. Delgado-Mena

Publications and source records attributed to E. Delgado-Mena.

58 records · Page 4Linked to original sources

arXiv2013

Volatile and refractory abundances of solar analogs with planets

We present a detailed abundance analysis of high-quality HARPS, UVES and UES spectra of 95 solar analogs, 33 with and 62 without detected planets. These spectra have S/N > 350. We investigate the possibility that the possible presence of terrestrial planets could affect the volatile-to-refratory abundance ratios. We do not see clear differences between stars with and without planets, either in the only seven solar twins or even when considering the whole sample of 95 solar analogs in the metallicity range -0.3< [Fe/H] < 0.5 . We demonstrate that after removing the Galactic chemical evolution effects the possible differences between stars with and without planets in these samples practically disappear and the volatile-to-refractory abundance ratios are very similar to solar values. We investigate the abundance ratios of volatile and refractory elements versus the condensation temperature of this sample of solar analogs, in particular, paying a special attention to those stars harbouring super-Earth-like planets.

astro-ph.EP↗

arXiv2011

Beryllium abundances in stars with planets:Extending the sample

Context: Chemical abundances of light elements as beryllium in planet-host stars allow us to study the planet formation scenarios and/or investigate possible surface pollution processes. Aims: We present here an extension of previous beryllium abundance studies. The complete sample consists of 70 stars hosting planets and 30 stars without known planetary companions. The aim of this paper is to further assess the trends found in previous studies with less number of objects. This will provide more information on the processes of depletion and mixing of light elements in the interior of late type stars, and will provide possible explanations for the abundance differences between stars that host planets and "single" stars. Methods: Using high resolution UVES spectra, we measure beryllium abundances of 26 stars that host planets and 1 "single" star mainly using the lambda 3131.065 A Be II line, by fitting synthetic spectra to the observational data. We also compile beryllium abundance measurements of 44 stars hosting planets and 29 "single" stars from the literature, resulting in a final sample of 100 objects. Results: We confirm that the beryllium content is roughly the same in stars hosting planets and in "single" stars at temperatures Teff > 5700K. The sample is still small for Teff < 5500K, but it seems that the scatter in Be abundances of dwarf stars is slightly higher at these cooler temperatures. Conclusions: We search for distinctive characteristics of planet hosts through correlations of Be abundance versus Li abundance, age, metallicity and oxygen abundance. These could provide some insight in the formation and evolution of planetary systems, but we did not find any clear correlation.

astro-ph.SR↗

arXiv2010

Volatiles and refratories in solar analogs: no terrestial planet connection

We have analysed very high-quality HARPS and UVES spectra of 95 solar analogs, 24 hosting planets and 71 without detected planets, to search for any possible signature of terrestial planets in the chemical abundances of volatile and refractory elements with respect to the solar abundances. We demonstrate that stars with and without planets in this sample show similar mean abundance ratios, in particular, a sub-sample of 14 planet-host and 14 "single" solar analogs in the metallicity range 0.14<[Fe/H]<0.36. In addition, two of the planetary systems in this sub-sample, containing each of them a super-Earth-like planet with masses in the range ~ 7-11 Earth masses, have different volatile-to-refratory abundance ratios to what would be expected from the presence of a terrestial planets. Finally, we check that after removing the Galactic chemical evolution effects any possible difference in mean abundances, with respect to solar values, of refratory and volatile elements practically dissappears.

astro-ph.EP↗

arXiv2010

Searching for the signatures of terrestial planets in solar analogs

We present a fully differential chemical abundance analysis using very high-resolution (R >~ 85,000) and very high signal-to-noise (S/N~800 on average) HARPS and UVES spectra of 7 solar twins and 95 solar analogs, 24 are planet hosts and 71 are stars without detected planets. The whole sample of solar analogs provide very accurate Galactic chemical evolution trends in the metalliciy range -0.3<[Fe/H]<0.5. Solar twins with and without planets show similar mean abundance ratios. We have also analysed a sub-sample of 28 solar analogs, 14 planet hosts and 14 stars without known planets, with spectra at S/N~850 on average, in the metallicity range 0.14<[Fe/H]<0.36 and find the same abundance pattern for both samples of stars with and without planets. This result does not depend on either the planet mass, from 7 Earth masses to 17.4 Jupiter masses, or the orbital period of the planets, from 3 to 4300 days. In addition, we have derived the slope of the abundance ratios as a function of the condensation temperature for each star and again find similar distributions of the slopes for both stars with and without planets. In particular, the peaks of these two distributions are placed at a similar value but with opposite sign as that expected from a possible signature of terrestial planets. In particular, two of the planetary systems in this sample, containing each of them a Super-Earth like planet, show slope values very close to these peaks which may suggest that these abundance patterns are not related to the presence of terrestial planets.

astro-ph.SR↗