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Element‐abundance inhomogeneity of interstellar matter as it follows from the chemical composition of the O‐type supergiants HDE 226868 (Cyg X‐1) and α Cam
Author(s) -
Bochkarev N.G.,
Karitskaya E.A.,
Shimanskii V.V.,
Galazutdinov G.A.
Publication year - 2013
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.201311933
Subject(s) - supergiant , physics , astrophysics , cepheid variable , interstellar medium , abundance of the chemical elements , spectral line , astronomy , galaxy , stars
By means of synthetic spectrum modeling with non‐LTE effects, we determined element abundances in the atmospheres of two O supergiants with similar physical characteristics: HDE 226868 (the optical component of Cyg X‐1) and α Cam. These objects are situated at the distance about 2.5 kpc from each other. HDE 226868 has higher abundances compared to α Cam. The differences of Al, S, Zn, and averaged CNO abundances are within 0.15–0.30 dex. This is in a good qualitative agreement with the inhomogeneity of the heavy‐element distribution over the Galactic disk derived by Luck et al. (2006) from Cepheids. This finding confirms the inhomogeneity of chemical‐element distribution on the scale of 2 kpc and is in agreement with the concept of interstellar‐matter superclouds preserving their intrinsic particularities on a time scale in excess of 1 Gyr. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)