X-ray emission from wind blown interstellar bubbles
II. ROSAT PSPC observations of S 308
Received 10 March 1997 / Accepted 16 November 1998
We have obtained ROSAT observations of several wind blown interstellar bubbles. In this paper we present the results of the PSPC observations of S 308 which optically shows a spherically symmetric shell with only slight hints on developing instabilities. It should therefore be a prototypical object for 1d and spherical 2d models. The X-ray surface brightness is very low. We have determined a total luminosity of and plasma temperatures in the range . The emitting volume is a thick shell with a ratio of inner to outer radius of . Both and the observed count rate surface profiles do not compare very well with predictions from current models. Also, the observed wind power is two orders of magnitude greater than needed as input by the models to produce the observed bubble. This stellar wind strength problem is similar to the one García-Segura and MacLow found in their numerical models for NGC 6888.
Key words: X-rays: ISM ISM: individual objects: S 308 ISM: bubbles stars: Wolf-Rayet stars: individual: EZ CMa
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© European Southern Observatory (ESO) 1999
Online publication: March 1, 1999