XMM - Newton Detection of Hot Gas in the Eskimo Nebula : Shocked Stellar Wind or Collimated Outflows ? ⋆
نویسنده
چکیده
The Eskimo Nebula (NGC 2392) is a double-shell planetary nebula (PN) known for the exceptionally large expansion velocity of its inner shell, ∼90 km s, 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 ∼ 2 × 106 K and an X-ray luminosity of LX = (2.6 ± 1.0) × 1031(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.
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