Winds of metal-poor OB stars: Updates from HST-COS UV spectroscopy

García, M.; Herrero, A.; Najarro, F.; Lennon, D. J.; Urbaneja, M. A.
Bibliographical reference

New windows on massive stars: asteroseismology, interferometry, and spectropolarimetry, Proceedings of the International Astronomical Union, IAU Symposium, Volume 307, pp. 41-46

Advertised on:
1
2015
Number of authors
5
IAC number of authors
1
Citations
1
Refereed citations
1
Description
In the race to break the SMC frontier and reach metallicity conditions closer to the First Stars the information from UV spectroscopy is usually overlooked. New HST-COS observations of OB stars in the metal-poor galaxy IC1613, with oxygen content ~1/10 solar, have proved the important role of UV spectroscopy to characterize blue massive stars and their winds. The terminal velocities (υ∞) and abundances derived from the dataset have shed new light on the problem of metal-poor massive stars with strong winds. Furthermore, our results question the υ∞-υ esc and υ∞-Z scaling relations whose use in optical-only studies may introduce large uncertainties in the derived mass loss rates and wind-momenta. Finally, our results indicate that the detailed abundance pattern of each star may have a non-negligible impact on its wind properties, and scaling these as a function of one single metallicity parameter is probably too coarse an approximation. Considering, for instance, that the [α/Fe] ratio evolves with the star formation history of each galaxy, we may be in need of updating all our wind recipes.