STScI Preprint #1268

On the Multiplicity of Carinae

The nebula around the luminous blue variable  Car is extremely N-rich and C,O-poor, indicative of CNO-cycle products. On the other hand, the recent HST-GHRS observation of the nucleus of  Car shows the spectrum of a star with stellar-wind lines of CII, CIV, SiII, SiIV etc. The spectrum is very similar to those of the LBV star P Cygni and of WN9/Ofpe stars. This line spectrum is indicative of a photosphere which is only mildly enhanced by CN-cycle products. This situation of a nebula that is chemically more advanced than the central star cannot be reached by the evolution of a single star. The dichotomy shows that the star whose spectrum now dominates the nucleus, was not the star that ejected the nebula. We discuss this evidence for multiplicity and combine it with the information about the 5.5 year periodicity in the emission lines.

Status:

Appeared in: The Astrophysical Journal, 505:L131-L133, 1998

Affiliations:

¹) Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
²) Astronomical Institute and SRON Laboratory for Space Research, Princetonplein 2, 3584CC Utrecht, The Netherlands.
³) On assignment from the Astrophysics Division, Space Science Department of ESA.