Near-IR spectroscopy of OH/IR stars in the Galactic centre
- Autor(en)
- Evelien Vanhollebeke, Joris A D L Blommaert, Bernhard Aringer
- Abstrakt
Context.Based on the expansion velocities of their circumstellar shells, Galactic centre (GC) OH/IR stars can be divided into two groups that are kinematically different and therefore believed to have evolved from different stellar populations.
Aims.We studied the metallicity distribution of the OH/IR stars population in the GC on the basis of a theoretical relation between EW(Na), EW(Ca), and EW(CO) and the metallicity.
Methods.For 70 OH/IR stars in the GC, we obtained near-IR spectra. The equivalent line-widths of Na I, Ca I, 12CO(2, 0), and the curvature of the spectrum around 1.6 ?m due to water absorption were determined.
Results.The near-IR spectrum of OH/IR stars is influenced by several physical processes. OH/IR stars are variable stars suffering high mass-loss rates. The dust that is formed around the stars strongly influences the near-IR spectra and reduces the equivalent line-widths of Na I and Ca I. A similar effect is caused by the water content in the outer atmosphere of the OH/IR star. Because of these effects, it is not possible to determine the metallicities of these stars with our low-resolution near-infrared spectroscopy.
- Organisation(en)
- Institut für Astrophysik
- Externe Organisation(en)
- Katholieke Universiteit Leuven
- Journal
- Astronomy & Astrophysics
- Band
- 455
- Seiten
- 645-652
- Anzahl der Seiten
- 8
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361:20065194
- Publikationsdatum
- 2006
- Peer-reviewed
- Ja
- ÖFOS 2012
- 103003 Astronomie
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/59bad989-a8a2-46b0-be37-de9ccf4cadaa