The evolved pulsating CEMP star HD 112869
- Vilnius University Observatory, Čiurlionio 29, Vilnius 2009 (Lithuania)
- Laser Center, University of Latvia, Raiņa bulvāris 19, LV-1586 Rīga (Latvia)
- Main Astronomical Observatory of Academy of Sciences of Ukraine, Zabolotnoho 27, Kyiv, 03680 (Ukraine)
- Special Astrophysical Observatory of the Russian AS, Nizhnij Arkhyz, 369167 (Russian Federation)
Radial velocity measurements, BVR{sub C} photometry, and high-resolution spectroscopy in the wavelength region from blue to near-infrared are employed in order to clarify the evolutionary status of the carbon-enhanced metal-poor star HD 112869 with a unique ratio of carbon isotopes in the atmosphere. An LTE abundance analysis was carried out using the method of spectral synthesis and new self-consistent 1D atmospheric models. The radial velocity monitoring confirmed semiregular variations with a peak-to-peak amplitude of about 10 km s{sup −1} and a dominating period of about 115 days. The light, color, and radial velocity variations are typical of the evolved pulsating stars. The atmosphere of HD 112869 appears to be less metal-poor than reported before, [Fe/H] = −2.3 ± 0.2 dex. Carbon-to-oxygen and carbon isotope ratios are found to be extremely high, C/O ≃ 12.6 and{sup 12}C/{sup 13}C ≳ 1500, respectively. The s-process elements yttrium and barium are not enhanced, but neodymium appears to be overabundant. The magnesium abundance seems to be lower than the average found for CEMP stars, [Mg/Fe] < +0.4 dex. HD 112869 could be a single low-mass halo star in the stage of asymptotic giant branch evolution.
- OSTI ID:
- 22882579
- Journal Information:
- Astrophysical Journal, Vol. 803, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
- Country of Publication:
- United Kingdom
- Language:
- English
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