TY - JOUR
T1 - On the importance of the interclump medium for superionization
T2 - O VI formation in the wind of ζ puppis
AU - Zsargó, J.
AU - Hillier, D. J.
AU - Bouret, J. C.
AU - Lanz, T.
AU - Leutenegger, M. A.
AU - Cohen, D. H.
PY - 2008
Y1 - 2008
N2 - We have studied superionization and X-ray line formation in the spectra of ζ Pup using our new stellar atmosphere code (XCMFGEN) that can be used to simultaneously analyze optical, UV, and X-ray observations. Here, we present results on the formation of the O vi λλ1032, 1038 doublet. Our simulations, supported by simple theoretical calculations, show that clumped wind models that assume void in the interclump space cannot reproduce the observed O vi profiles. However, enough O vi can be produced if the voids are filled by a lowdensity gas. The recombination of O vi is very efficient in the dense material, but in the tenuous interclump region an observable amount of O vi can be maintained. We also find that different UV resonance lines are sensitive to different density regimes in ζ Pup: C iv is almost exclusively formed within the densest regions, while the majority of O vi resides between clumps. N v is an intermediate case, with contributions from both the tenuous gas and clumps.
AB - We have studied superionization and X-ray line formation in the spectra of ζ Pup using our new stellar atmosphere code (XCMFGEN) that can be used to simultaneously analyze optical, UV, and X-ray observations. Here, we present results on the formation of the O vi λλ1032, 1038 doublet. Our simulations, supported by simple theoretical calculations, show that clumped wind models that assume void in the interclump space cannot reproduce the observed O vi profiles. However, enough O vi can be produced if the voids are filled by a lowdensity gas. The recombination of O vi is very efficient in the dense material, but in the tenuous interclump region an observable amount of O vi can be maintained. We also find that different UV resonance lines are sensitive to different density regimes in ζ Pup: C iv is almost exclusively formed within the densest regions, while the majority of O vi resides between clumps. N v is an intermediate case, with contributions from both the tenuous gas and clumps.
KW - Stars:early-type
KW - Stars:winds, outflows
KW - X-rays:individual (ζ puppis)
KW - X-rays:stars
UR - http://www.scopus.com/inward/record.url?scp=57349090257&partnerID=8YFLogxK
U2 - 10.1086/592568
DO - 10.1086/592568
M3 - Artículo
SN - 0004-637X
VL - 685
SP - L149-L152
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2 PART 2
ER -