The Eskimo Nebula ( NGC 2392 ) is a double-shell planetary nebula ( PN ) known for the exceptionally large expansion velocity of its inner shell , \sim 90 km s ^ { -1 } , and the existence of a fast bipolar outflow with a line-of-sight expansion velocity approaching 200 km s ^ { -1 } .
We have obtained XMM-Newton observations of the Eskimo and detected diffuse X-ray emission within its inner shell .
The X-ray spectra suggest thin plasma emission with a temperature of \sim 2 \times 10 ^ { 6 } K and an X-ray luminosity of L _ { X } = ( 2.6 \pm 1.0 ) \times 10 ^ { 31 } ( d / 1150 ~ { } { pc } ) ^ { 2 } ergs s ^ { -1 } , where d is the distance in parsecs .
The diffuse X-ray emission shows noticeably different spatial distributions between the 0.2–0.65 keV and 0.65–2.0 keV bands .
High-resolution X-ray images of the Eskimo are needed to determine whether its diffuse X-ray emission originates from shocked fast wind or bipolar outflows .