Sakurai's Object: characterising the near-infrared CO ejecta between 2003 and 2007

Abstract

We present observations of Sakurai's Object obtained at 1-5um between 2003 and 2007. By fitting a radiative transfer model to an echelle spectrum of CO fundamental absorption features around 4.7um, we determine the excitation conditions in the line-forming region. We find 12C/13C~3.5, consistent with CO originating in ejecta processed by the very late thermal pulse, rather than in the pre-existing planetary nebula. We demonstrate the existence of 2.2e-6<M<2.7e-6 Msun of CO ejecta outside the dust, forming a high-velocity wind of 500+/-80 km/s. We find evidence for significant weakening of the CO band and cooling of the dust around the central star between 2003 and 2005. The gas and dust temperatures are implausibly high for stellar radiation to be the sole contributor.

6 pages, 3 figures, 2 tables

References in corpus (6)

• The evolutionary time scale of Sakurai's object: A test of convection theory?
• Hubble Space Telescope Survey of Interstellar ^12CO/^13CO in the Solar Neighborhood
• The onset of photoionization in Sakurai's Object (V4334 Sgr)
• CO bands in V4334 Sgr (Sakurai's Object): the 12C/13C ratio
• The Spitzer IRS view of V4334 Sgr (Sakurai's Object)
• Warm high velocity CO in the wind of Sakurai's Object (= V4334 Sgr)

Cited by in corpus (4)

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• The infrared view of dust and molecules around V4334 Sgr (Sakurai's Object): a 20-year retrospective
• (sub)Millimeter Emission Lines of Molecules in Born-again Stars
• V4334 Sgr (Sakurai's Object): still churning out the dust