Letter to the Editor

XMM-Newton detection of hot gas in the Eskimo Nebula: Shocked stellar wind or collimated outflows?^*

¹ Instituto de Astrofísica de Andalucía, CSIC, Apartado Correos 3004, 18080, Granada, Spain e-mail: mar@iaa.es
² Astronomy Department, University of Illinois, 1002 W. Green Street, Urbana, IL 61801, USA e-mail: [chu;gruendl]@astro.uiuc.edu
³ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA e-mail: meixner@stsci.edu

Received: 1 December 2004
Accepted: 19 December 2004

Abstract

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^-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 ~2  10⁶ K and an X-ray luminosity of    erg 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.