The Spitzer IRS view of V4334 Sgr (Sakurai's Object)

Abstract

We present an observation of the very late thermal pulse object V4334 Sgr (Sakurai's Object) with the Infrared Spectrometer (IRS) on the Spitzer Space Telescope. The emission from 5-38 microns is dominated by the still-cooling dust shell. A number of features are seen in absorption against the dust shell, which we attribute to HCN and polyyne molecules. We use these features to determine the 12C/13C ratio for the absorbing gas to be ~ 3.2 (+3.2,-1.6}; this implies that, despite the H-content of the molecules, the hydrocarbon-bearing gas must have originated in material produced in the very late thermal pulse. We see no evidence of emission lines, despite the recently-reported optical and radio observations that suggest the effective temperature of the stellar remnant is rising.

arXiv comment5 pages, 6 figures. Accepted for publication in MNRAS

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• The evolutionary time scale of Sakurai's object: A test of convection theory?
• CO bands in V4334 Sgr (Sakurai's Object): the 12C/13C ratio
• Warm high velocity CO in the wind of Sakurai's Object (= V4334 Sgr)
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• Evolution of the 1919 Ejecta of V605 Aquilae
• The born-again planetary nebula A78: an X-ray twin of A30
• Dust around R Coronae Borealis stars: II. Infrared emission features in a H-poor environment
• Carbon dust in the evolved born-again planetary nebulae A30 and A78
• The infrared view of dust and molecules around V4334 Sgr (Sakurai's Object): a 20-year retrospective
• Hidden IR structures in NGC 40: signpost of an ancient born-again event
• Discovery of a Fast Expanding Shell in the Inside-out Born-Again Planetary Nebula HuBi 1 Through High-Dispersion Integral Field Spectroscopy
• Sakurai's Object: characterising the near-infrared CO ejecta between 2003 and 2007
• (sub)Millimeter Emission Lines of Molecules in Born-again Stars
• V4334 Sgr (Sakurai's Object): still churning out the dust
• Dust changes in Sakurai's Object: new PAHs and SiC with coagulation of submicron-sized silicate dust into 10 micron-sized melilite grains
• Dramatic infrared variability of WISE J1810-3305: catching early dust ejection during the thermal pulse of an AGB star?
• VVV-WIT-01: highly obscured classical nova or protostellar collision?
• First images of the molecular gas around a born-again star revealed by ALMA
• Recurrent Novae: Progenitors of SN Ia?
• The circumstellar dust of "Born-Again" stars