A carbon-rich hot bubble in the planetary nebula NGC 5189

Abstract

We present the discovery of extended X-ray emission from the planetary nebula (PN) NGC 5189 around the [WO1]-type WD 1330-657 with XMM-Newton. The X-ray-emitting gas fills the cavities detected in the Hubble Space Telescope [O III] narrow-band image and presents a limb-brightened morphology towards the outer edges of the east and west lobes. The bulk of the X-ray emission is detected in the soft (0.3 - 0.7 keV) band with the XMM-Newton EPIC spectra dominated by the C VI Ly$\hat{I}\pm$ line at 0.37 keV (=33.7 Ã ). Spectral analysis resulted in carbon and neon abundances 38 and 6 times their solar values, with a plasma temperature of $kT=0.14\pm 0.01$ keV ($T=1.6\times 10^6$ K) and X-ray luminosity of $L_{\mathrm{X}}=(2.8\pm 0.8)\times 10^{32}$ erg s${}^{-1}$. NGC 5189 is an evolved and extended PN ($\lesssim$0.70 pc in radius), thus, we suggest that the origin of its X-ray emission is consistent with the born-again scenario in which the central star becomes carbon-rich through an eruptive very late thermal pulse, subsequently developing a fast, carbon-rich wind powering the X-ray emission as suggested for A30 and A78.

9 pages; 5 figures and 1 table; Accepted to ApJ