| Abstract : | Planetary nebulae (PN) represent the end stages of the evolution of stars with ZAMS 8.0 M⊙, and are formed by the material shed from the post-MS star, as it completes its evolution on the AGB and post-AGB branches. X-ray studies of PN with Chandra ( e.g. J. H. Kastner et al., 2012, AJ 144, 58) and XMM-Newton have revealed the presence (and, more notably, the absence) of X-ray bright central point sources (CS) in several PN, with a hard X-ray excess suggesting the presence of binary companions. In this study, we use Astrosat/SXT 0.3-8 keV data, taken as part of an Astrosat multi-wave band program on PN, to study the x-ray spectral signatures of both the CS and nebulae, from several, nearby PN with well-resolved structures in the UV. Despite the low count-rate (e.g., only (1.021 ±0.5147) × 10^{−2} s^{-1}) in the case of NGC 3587 at 622 pc), and relatively short exposure times, the spectrum for this source is best fit by an absorbed thermal plasma model (XSpec wabs*mekal), with the solar abundances, a column density of
NH = 7.86×10^{19} cm{−2}, and temperature kT = 0.775912 keV in the absence of a hard x-ray component, and we attribute all x-ray emissions to the nebula itself. |
