Macroclumping as solution of the discrepancy between Hα and P v mass loss diagnostics for O-type stars

0424407 - ASÚ 2014 RIV FR eng J - Journal Article
Šurlan, Brankica - Hamann, W.-R. - Aret, A. - Kubát, Jiří - Oskinova, L.M. - Torres, A.F.
Macroclumping as solution of the discrepancy between Hα and P v mass loss diagnostics for O-type stars.
Astronomy & Astrophysics. Roč. 559, November (2013), A130/1-A130/17. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA ČR(CZ) GAP209/11/1198; GA MŠMT 7AMB12AR021
Grant - others:NASA(US) NNX09AF08G
Institutional support: RVO:67985815
Keywords : stars * winds * outflows
Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
Impact factor: 4.479, year: 2013

In a previous paper, we presented 3D Monte-Carlo calculations for the formation of scattering lines in a clumped stellar wind. In the present paper We selected five O-type supergiants (from O4 to O7) and tested whether the reported discrepancies can be resolved using the assumption of macroclumping in the stellar wind. Our results show that with the mass-loss rates that fit Hα (and other Balmer and He ii lines), the UV resonance lines (especially the unsaturated doublet of P v) can also be reproduced with no problem when macroclumping is taken into account. There is no need to artificially reduce the mass-loss rates or to assume a subsolar phosphorus abundance or an extremely high clumping factor, unlike what was claimed by other authors. These consistent mass-loss rates are lower by a factor of 1.3 to 2.6, compared to the mass-loss rate recipe from Vink et al.
Permanent Link: http://hdl.handle.net/11104/0230468