Spectroscopic analysis of the SB3 system 74Aqr†
Abstract
In this paper, we present the first quantitative abundance analysis of the SB3 system whose primary is the well-known mercury-manganese (HgMn) star 74Aqr (= HD216494). From the fit of the Hβ profile, obtained at the orbital phase of maximum separation between A and B components, we determined the effective temperatures and surface gravities of each component: TAeff = 12000 K, loggA = 3.70, TBeff = 11500 K, loggB = 3.90 and TCeff = 11500 K, loggC = 4.10. These values are validated by the coincidence of abundances derived from different ionization states of iron.
We find that this system is heterogeneous from the point of view of the chemical composition: HD216494A shows the typical spectral features, with the exception of strontium underabundance, of HgMn stars. Apart from a mild helium underabundance and overabundance of two rare earths (praseodymium and neodymium), HD216494B does not show any other anomaly. The fast rotating C component, in spite of the difficulties found in the identification of its spectral lines, seems to be the only normal star of the system. Based on data obtained from the ESO Science Archive Facility under request number GCATANZARO43200 and GCATANZARO43204. Partially based on observations made with the INAF - Catania Astrophysical Observatory telescope. ‡ E-mail: gca@oact.inaf.it § Guest User, Canadian Astronomy Data Centre, which is operated by the Dominion Astrophysical Observatory for the National Research Council of Canada's Herzberg Institute of Astrophysics.- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- November 2006
- DOI:
- 10.1111/j.1365-2966.2006.11039.x
- Bibcode:
- 2006MNRAS.373..330C
- Keywords:
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- stars: abundances;
- stars: chemically peculiar;
- stars: individual: 74Aqr