Abundance analysis of planet-hosting and debris-disk stars

Abstract: We present an analysis of element abundances in planet-hosting and debrisdisk stars based on high-resolution spectra obtained with the FEROS echelle spectrograph and the 2.2-m ESO telescope at La Silla. Atmospheric parameters and abundance patterns for the stars are determined. A comparison of the abundances is made between planethosting stars, debris-disk stars, and field starshttp://astars2013.inasan.ru/proceedings/publishedVersionFil: Carolina Andrea Chavero. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Astronomía (incluye Astrofísica y Ciencias del Espacio

Abundance Pattern Analysis of Planet-hosting and Debris-disk Stars

Abstract: About 16 % of the main-sequence solar-like stars are surrounded by dusty debris disks (DD). These disks are the detritus of small bodies collisions and their presence is a very strong signpost of planet formation. One of the most interesting characteristics of stars hosting a giant planet is a direct relationship between metallicity and probability of planet formation, which was found to increase with stellar metallicity Gonzalez (1997). Instead, the small planets would form around host stars (HS) with a wide range of metallicities (Buchhave et al. 2012). On the other hand the presence of debris disks is uncorrelated with metallicity (Chavero et al. 2006, Greaves et al. 2006, Maldonado et al. 2012).http://www.aspbooks.org/a/volumes/article_details/?paper_id=36464Fil: Chavero, Carolina Andrea. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Chavero, Carolina Andrea. Conicet. Argentina.Astronomía (incluye Astrofísica y Ciencias del Espacio

Spectroscopic signatures of magnetospheric accretion in Herbig Ae/Be stars. I. The case of HD101412

Models of magnetically-driven accretion and outflows reproduce many observational properties of T Tauri stars. This concept is not well established for the more massive Herbig Ae/Be stars. We intend to examine the magnetospheric accretion in Herbig Ae/Be stars and search for rotational modulation using spectroscopic signatures, in this first paper concentrating on the well-studied Herbig Ae star HD101412. We used near-infrared spectroscopic observations of the magnetic Herbig Ae star HD101412 to test the magnetospheric character of its accretion disk/star interaction. We reduced and analyzed 30 spectra of HD101412, acquired with the CRIRES and X-shooter spectrographs installed at the VLT (ESO, Chile). The spectroscopic analysis was based on the He I lambda 10,830 and Pa gamma lines, formed in the accretion region. We found that the temporal behavior of these diagnostic lines in the near-infrared spectra of HD101412 can be explained by rotational modulation of line profiles generated by accreting gas with a period P = 20.53+-1.68 d. The discovery of this period, about half of the magnetic rotation period P_m = 42.076 d previously determined from measurements of the mean longitudinal magnetic field, indicates that the accreted matter falls onto the star in regions close to the magnetic poles intersecting the line-of-sight two times during the rotation cycle. We intend to apply this method to a larger sample of Herbig Ae/Be stars.Comment: 8 pages, 1 table, 7 figures, accepted for publication in A&