An Abundance Analysis of the New Carbon-rich Proto-Planetary Nebula IRAS 06530-0213
Abstract
In this paper we present a study of the proto-planetary nebula (PPN) IRAS 06530-0213 based on low- and high-resolution spectra. The low-resolution spectrum shows that the star is an F5 supergiant with molecular C2 and C3 and enhanced s-process lines. From the high-resolution spectra, the following atmospheric parameters were determined: Teff=6900 K, logg=1.0, and ξt=4.5. Abundance analysis shows that IRAS 06530-0213 is metal-poor ([Fe/H]=-0.9) and overabundant in carbon ([C/Fe]=1.3), nitrogen ([N/Fe]=1.0), and s-process elements ([s-process/Fe]=1.9), indicating asymptotic giant branch (AGB) nucleosynthesis and deep convective mixing. From the analysis of circumstellar C2 and CN molecular bands in the spectrum of IRAS 06530-0213, an envelope expansion velocity of Vexp=14+/-1 km s-1 was determined, a typical value for post-AGB stars. Also typical of PPNs is the double-peaked spectral energy distribution. The properties of both the photosphere and circumstellar envelope suggest that IRAS 06530-0213 is unambiguously a low-mass, carbon-rich PPN. For comparison purposes, new, high-resolution spectra of the well-known PPN HD 56126 (IRAS 07134+1005) were also analyzed and compared with previous results.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2003
- DOI:
- 10.1086/375191
- arXiv:
- arXiv:astro-ph/0303234
- Bibcode:
- 2003ApJ...590.1049H
- Keywords:
-
- Stars: Circumstellar Matter;
- Stars: Abundances;
- Stars: AGB and Post-AGB;
- Stars: Individual: Henry Draper Number: HD 56126;
- Stars: Individual: Alphanumeric: IRAS 06530-0213;
- Astrophysics
- E-Print:
- Scheduled for publication in ApJ,590, 20 June 2003 issue