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PHYSICAL STRUCTURE OF THE PLANETARY NEBULA NGC 3242 FROM THE HOT BUBBLE TO THE NEBULAR ENVELOPE

Journal Article · · Astronomical Journal (New York, N.Y. Online)
;  [1];
  1. Instituto de Astrofisica de Andalucia, CSIC, Granada 18008 (Spain)
One key feature of the interacting stellar winds model of the formation of planetary nebulae (PNe) is the presence of shock-heated stellar wind confined in the central cavities of PNe. This so-called hot bubble should be detectable in X-rays. Here we present XMM-Newton observations of NGC 3242, a multiple-shell PN whose shell morphology is consistent with the interacting stellar winds model. Diffuse X-ray emission is detected within its inner shell with a plasma temperature of {approx}2.35 x 10{sup 6} K and an intrinsic X-ray luminosity of {approx}2 x 10{sup 30} erg s{sup -1} at the adopted distance of 0.55 kpc. The observed X-ray temperature and luminosity are in agreement with 'ad hoc' predictions of models including heat conduction. However, the chemical abundances of the X-ray-emitting plasma seem to imply little evaporation of cold material into the hot bubble, whereas the thermal pressure of the hot gas is unlikely to drive the nebular expansion as it is lower than that of the inner shell rim. These inconsistencies are compounded by the apparent large filling factor of the hot gas within the central cavity of NGC 3242.
OSTI ID:
21582878
Journal Information:
Astronomical Journal (New York, N.Y. Online), Journal Name: Astronomical Journal (New York, N.Y. Online) Journal Issue: 3 Vol. 142; ISSN 1538-3881
Country of Publication:
United States
Language:
English