Poster abstract details

Early Results from ChanPLaNS: Mystery of Hard X-ray Emitting CSPNe
R. Montez Jr., J. H. Kastner, B. Balick, E. Behar, E. Blackman, V. Bujarrabal, Y.-H. Chu, R. Corradi, O. De Marco, A. Frank, D. Frew, M. Guerrero, S. Kwok, B. Miszalski, J. Nordhaus, Q. Parker, R. Sahai, C. Sandin, D. Schoenberner, N. Soker, J. Sokoloski, W. Steffen, T. Ueta, E. Villaver, A. Zijlstra

Abstract

We are presently using the Chandra X-ray Observatory to conduct the first systematic X-ray survey of planetary nebulae (PNe) in the solar neighborhood. The Chandra Planetary Nebula Survey (ChanPlaNS) is a 570 ks Chandra Cycle 12 Large Program targeting 21 high-excitation PNe within ~1.5 kpc of Earth. When complete, this survey will provide a suite of new X-ray diagnostics that will inform the study of late stellar evolution, binary star astrophysics, and wind interactions. Among the early results of ChanPlaNS (when combined with archival Chandra data) is a surprisingly high detection rate of relatively hard X-ray emission from CSPNe. Specifically, X-ray point sources are clearly detected in roughly half of all 28 PNe observed thus far by Chandra, and all but one of these X-ray-emitting CSPNe display evidence for a hard (few MK) component in their Chandra spectra. Only the central star of the Dumbbell appears to display "pure" hot blackbody emission from a ~200 kK hot white dwarf photosphere in the X-ray band. Potential explanations for the "excess" hard X-ray emission detected from the other CSPNe include late-type companions (heretofore undetected, in most cases) whose coronae have been rejuvenated by recent interactions with the mass-losing WD progenitor, non-LTE effects in hot white dwarf photospheres, and slow (re-)accretion of previously ejected red giant envelope mass. We discuss these and other potential constraints on the origin and evolution of PNe and their central stars imposed by the early ChanPlaNS results.