We report the serendipitous detection of the planetary nebula NGC 5315 by the Chandra X-ray Observatory .
The Chandra imaging spectroscopy results indicate that the X-rays from this PN , which harbors a Wolf-Rayet ( WR ) central star , emanate from a T _ { X } \sim 2.5 \times 10 ^ { 6 } K plasma generated via the same wind-wind collisions that have cleared a compact ( \sim 8000 AU radius ) central cavity within the nebula .
The inferred X-ray luminosity of NGC 5315 is \sim 2.5 \times 10 ^ { 32 } erg s ^ { -1 } ( 0.3-2.0 keV ) , placing this object among the most luminous such “ hot bubble ” X-ray sources yet detected within PNe .
With the X-ray detection of NGC 5315 , objects with WR-type central stars now constitute a clear majority of known examples of diffuse X-ray sources among PNe ; all such “ hot bubble ” PN X-ray sources display well-defined , quasi-continuous optical rims .
We therefore assert that X-ray-luminous hot bubbles are characteristic of young PNe with large central star wind kinetic energies and closed bubble morphologies .
However , the evidence at hand also suggests that processes such as wind and bubble temporal evolution , as well as heat conduction and/or mixing of hot bubble and nebular gas , ultimately govern the luminosity and temperature of superheated plasma within PNe .