The born-again planetary nebula A78: an X-ray twin of A30

Abstract

We present the XMM-Newton discovery of X-ray emission from the planetary nebula (PN) A78, the second born-again PN detected in X-rays apart from A30. These two PNe share similar spectral and morphological characteristics: They harbor diffuse soft X-ray emission associated with the interaction between the H-poor ejecta and the current fast stellar wind, and a point-like source at the position of the central star (CSPN). We present the spectral analysis of the CSPN, using for the first time a NLTE code for expanding atmospheres which takes line blanketing into account for the UV and optical spectra. The wind abundances are used for the X-ray spectral analysis of the CSPN and the diffuse emission. The X-ray emission from the CSPN in A78 can be modeled by a single C VI emission line, while the X-ray emission from its diffuse component is better described by an optically thin plasma emission model with temperature $kT$=0.088 keV ($T\approx$1.0$\times$10${}^6$ K). We estimate X-ray luminosities in the 0.2--2.0 keV energy band of $L_{\mathrm{X},\mathrm{CSPN}}$=(1.2$\pm$0.3)$\times$10${}^{31}$ erg~s${}^{-1}$ and $L_{\mathrm{X},\mathrm{DIFF}}$=(9.2$\pm$2.3)$\times$10${}^{30}$ erg~s${}^{-1}$ for the CSPN and diffuse components, respectively.

12 pages, 10 figures, 2 tables; Accepted to Astrophysical Journal

References in corpus (6)

• Fe emission and ionized excess absorption in the luminous quasar 3C109 with XMM-Newton
• The hydrogen-deficient knot of the `born again' planetary nebula Abell 58 (V605 Aql)
• The Chandra Planetary Nebula Survey (ChanPlaNS). II. X-ray Emission from Compact Planetary Nebulae
• The born again (VLTP) scenario revisited: The mass of the remnants and implications for V4334 Sgr
• The Spitzer IRS view of V4334 Sgr (Sakurai's Object)
• Expansion of hydrogen-poor knots in the born-again planetary nebulae A30 and A78

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• Hidden IR structures in NGC 40: signpost of an ancient born-again event
• WR 72: a born-again planetary nebula with hydrogen-poor knots
• (sub)Millimeter Emission Lines of Molecules in Born-again Stars
• A carbon-rich hot bubble in the planetary nebula NGC 5189
• Formation and fate of the born-again planetary nebula HuBi 1
• Common envelope evolution in born-again planetary nebulae -- Shaping the H-deficient ejecta of A30
• A primer on the formation and evolution of hydrogen deficient Central Stars of Planetary Nebulæ and Related Objects
• Hot bubbles of planetary nebulae with hydrogen-deficient winds. III. Formation and evolution in comparison with hydrogen-rich bubbles