Stellar spectroscopy far beyond the Local Group
Abstract
Multi-object spectroscopic observations of blue supergiants in NGC 3621, a spiral galaxy at a distance of 6.7 Mpc, carried out with the ESO VLT and FORS are presented. We demonstrate the feasibility of quantitative stellar spectroscopy at distances approaching a ten-fold increase over previous investigations by determining chemical composition, stellar parameters, reddening, extinction and wind properties of one of our targets, a supergiant of spectral type A1 Ia located in the outskirts of NGC 3621. The metallicity (determined from iron group elements) is reduced by a factor of two relative to the sun in qualitative agreement with results from previous abundance studies based on H II region oxygen emission lines. Reddening and extinction are E(B-V) = 0.12 and Av = 0.37, respectively, mostly caused by the galactic foreground. Comparing stellar wind momentum and absolute V magnitude with galactic and M31 counterparts we confirm the potential of the wind momentum-luminosity relationship as an alternative tool to estimate extragalactic distances.
Cite
@article{arxiv.astro-ph/0012372,
title = {Stellar spectroscopy far beyond the Local Group},
author = {Fabio Bresolin and Rolf-Peter Kudritzki and Roberto H. Mendez and Norbert Przybilla},
journal= {arXiv preprint arXiv:astro-ph/0012372},
year = {2014}
}
Comments
9 pages, 4 figures, 1 table, accepted for publication in The Astrophysical Journal Letters