The Wolf-Rayet ( WR ) bubble S 308 around the WR star HD 50896 is one of the only two WR bubbles known to possess X-ray emission .
We present XMM-Newton observations of three fields of this WR bubble that , in conjunction with an existing observation of its Northwest quadrant , map most of the nebula .
The X-ray emission from S 308 displays a limb-brightened morphology , with a central cavity \sim 22′ in size and a shell thickness of \sim 8′ .
This X-ray shell is confined by the optical shell of ionized material .
The spectrum is dominated by the He-like triplets of N vi at 0.43 keV and O vii at 0.57 keV , and declines towards high energies , with a faint tail up to 1 keV .
This spectrum can be described by a two-temperature optically thin plasma emission model ( T _ { 1 } \sim 1.1 \times 10 ^ { 6 } K , T _ { 2 } \sim 13 \times 10 ^ { 6 } K ) , with a total X-ray luminosity \sim 2 \times 10 ^ { 33 } erg s ^ { -1 } at the assumed distance of 1.5 kpc .