2012A&A...542A..53V -
Astronomy and Astrophysics, volume 542A53-53 (2012/6-1)
IRAS 11472-0800: an extremely depleted pulsating binary post-AGB star.
VAN WINCKEL H., HRIVNAK B.J., GORLOVA N., GIELEN C. and LU W.
Abstract (from CDS):
We focus here on one particular and poorly studied object, IRAS11472-0800. It is a highly evolved post-asymptotic giant branch (post-AGB) star of spectral type F, with a large infrared excess produced by thermal emission of circumstellar dust. We deployed a multi-wavelength study that includes the analyses of optical and IR spectra as well as a variability study based on photometric and spectroscopic time-series. The spectral energy distribution (SED) properties as well as the highly processed silicate N-band emission show that the dust in IRAS11472-0800 is likely trapped in a stable disc. The energetics of the SED and the colour variability show that our viewing angle is close to edge-on and that the optical flux is dominated by scattered light. With photospheric abundances of [Fe/H]=-2.7 and [Sc/H]=-4.2, we discovered that IRAS11472-0800 is one of the most chemically-depleted objects known to date. Moreover, IRAS11472-0800 is a pulsating star with a period of 31.16 days and a peak-to-peak amplitude of 0.6mag in V. The radial velocity variability is strongly influenced by the pulsations, but the significant cycle-to-cycle variability is systematic on a longer time scale, which we interpret as evidence for binary motion. We conclude that IRAS11472-0800 is a pulsating binary star surrounded by a circumbinary disc. The line-of-sight towards the object lies close to the orbital plane, therefore the optical light is dominated by scattered light. IRAS11472-0800 is one of the most chemically-depleted objects known so far and links the dusty RVTauri stars to the non-pulsating class of strongly depleted objects.
Abstract Copyright:
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Journal keyword(s):
stars: AGB and post-AGB - binaries: general - binaries: spectroscopic - stars: chemically peculiar - stars: evolution - stars: abundances
VizieR on-line data:
<Available at CDS (J/A+A/542/A53): table3.dat table6.dat>
Simbad objects:
18
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