AAS 206th Meeting, 29 May - 2 June 2005
Session 6 Formation and Fate of Stardust
Poster, Monday, 9:20am-6:30pm, Tuesday, 10:00am-7:00pm, May 30, 2005, Ballroom A

Previous   |   Session 6   |   Next

[6.10] X-ray Imaging of Planetary Nebulae with Wolf-Rayet-type Central Stars

J.H. Kastner (Rochester Institute of Technology), R. Montez (University of Rochester), O. De Marco (American Museum of National History), N. Soker (Technion-Israel Institute of Technology, Haifa, Israel)

We report the detection by the Chandra X-ray Observatory (CXO) of diffuse X-ray emission from NGC 40, a planetary nebula (PN) with a late-type ([WC8]), Wolf-Rayet central star. Such ``[WC] PNs'' are presently driving fast (200-1000 km s-1), massive winds into denser, slow-moving (~10 km s-1) material ejected during recently terminated asymptotic giant branch evolutionary phases. Hence, X-ray observations of [WC] PNs should provide insight into the nature of energetic wind-wind shocks. The X-ray surface brightness of NGC 40, which is near the limit of detectability of CXO's Advanced CCD Imaging Spectrometer (ACIS) in our 20 ks exposure, is distributed within a partial annulus with outer radius Ro ~20'' and inner radius Ri ~10''. This annulus is nested within ring-like nebulosity observed in near-infrared images. The detection of annular X-ray emission suggests that in this PN the X-ray emitting gas results from the fast wind of the central star, rather than from the jet activity that is apparent in optical imaging of NGC 40. We also obtained a 29 ks CXO/ACIS exposure of Hen 2-99, which harbors a [WC9] nucleus, and failed to detect X-ray emission. Combining these results with previous X-ray detections and nondetections of PNs by CXO and XMM-Newton, we find evidence for a link between the evolutionary timescales of X-ray and infrared emission from PNs.

This research is supported by NASA through Chandra award number GO4--5169X issued to Rochester Institute of Technology by the Chandra X-ray Observatory Center, which is operated by Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8--03060.

Previous   |   Session 6   |   Next

Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.