000001870 001__ 1870
000001870 005__ 20160701171654.0
000001870 0247_ $$2DOI$$a10.1016/S1384-1076(97)00018-3
000001870 037__ $$aASTROimport-27
000001870 100__ $$avan der Hucht, K. A.
000001870 245__ $$aThe Hipparcos distance determination of the Wolf-Rayet system γ2 Velorum (WC8+O) and its ramifications
000001870 260__ $$c1997
000001870 520__ $$aHipparcos parallax measurements give a distance to the Wolf-Rayet WC8+O spectroscopic binary γ2 Vel of d = 258 -31+41 pc and a distance to the O4I(n)f star ξ Pup of d = 429 -77+120pc. Adopting for γ2 Vel an interstellar extinction of Aν = 0.06 mag, this implies an absolute magnitude M ν = - 5.4 mag for the WC8+O binary system. Given that the binary components have a magnitude difference Δm = 1.4 mag, we derive M ν(WC8) = -3.7 and M v(O) = -5.0 mag. The latter indicates an O8.5III rather than an O9I companion, as was adopted during the last 25 years. Apparently γ2 Vel is not a member of, but a foreground object before the open cluster Cr 173 and the association Vel OB2. Given a re-assessment of the distance of the Gum Nebula, γ2 Vel is still one of its ionizing sources, while ξ Pup appears to be located at the back of the Gum Nebula. Consequences of the Hipparcos distance determination of γ2 Vel for its mass, mass loss rate, luminosities at various wavelengths, and, briefly, its association with the Gum Nebula, are discussed. 
000001870 700__ $$a Schrijver, H.
000001870 700__ $$a Stenholm, B.
000001870 700__ $$a Lundström, I.
000001870 700__ $$a Moffat, A. F. J.
000001870 700__ $$a Marchenko, S. V.
000001870 700__ $$a Seggewiss, W.
000001870 700__ $$a Setia Gunawan, D. Y. A.
000001870 700__ $$a Sutantyo, W.
000001870 700__ $$a van den Heuvel, E. P. J.
000001870 700__ $$a De Cuyper, J.-P.
000001870 700__ $$a Gómez, A. E.
000001870 773__ $$c245-250$$i3$$pNew Astronomy$$v2$$y1997
000001870 85642 $$ahttp://esoads.eso.org/abs/1997NewA....2..245V
000001870 905__ $$apublished in
000001870 980__ $$aREFERD