Chemical composition of components of the binary lithium star ? Peg

Lyubimkov, L. S.; Polosukhina, N. S.; Rosgopchin, S. I.

doi:10.1007/bf01004672

Cited by 6 publications

(13 citation statements)

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“…As an example we take the binary system  Peg (HR 8430), to which a special method described in Ref. 24 has been applied [27], in order to obtain the individual parameters of the components, including T eff , logg, and the lithium abundance log (Li). The difference of 0.67 dex in the values of log (Li) for the components yielded an estimated age of 200  t million years.…”

Section: Evolution Of the Lithium Abundance In The Atmospheres Of Dwa...mentioning

confidence: 99%

Lithium in Stellar Atmospheres: Observations and Theory

Lyubimkov

2016

Astrophysics

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Of all the light elements, lithium is the most sensitive indicator of stellar evolution. This review discusses current data on the abundance of lithium in the atmospheres of A-, F-, G-, and K-stars of different types, as well as the consistency of these data with theoretical predictions. The variety of observed Li abun-dances is illustrated by the following objects in different stages of evolution: (1) Old stars in the galactic halo, which have a lithium abundance log ԑ(Li)=2.2 (the "lithium plateau") that appears to be 0.5 dex lower than the primordial abundance predicted by cosmological models. (2) Young stars in the galactic disk, which have been used to estimate the contemporary initial lithium abundance log ԑ(Li)=3.2±0.1 for stars in the Main sequence. Possible sources of lithium enrichment in the interstellar medium during evolution of the galaxy are discussed. (3) Evolving FGK dwarfs in the galactic disk, which have lower log ԑ(Li) for lower effective temperature T eff and mass M. The "lithium dip" near T eff~6 600 K in the distribution of log ԑ(Li) with respect to T eff in old clusters is discussed. (4) FGK giants and supergiants, of which most have no lithium at all. This phenomenon is consistent with rotating star model calculations.(5) Lithium rich cold giants with log ԑ(Li) ≥2.0 , which form a small, enigmatic group. Theoretical models with rotation can explain the existence of these stars only in the case of low initial rotation velocities V 0 <50 km/s. In all other cases it is necessary to assume recent synthesis of lithium (capture of a giant planet is an alternative). (6) Magnetic Ap-stars, where lithium is concentrated in spots located at the magnetic poles. There the lithium abundance reaches log ԑ(Li)=6. Discrepancies between observa-tions and theory are noted for almost all the stars discussed in this review.

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Section: Evolution Of the Lithium Abundance In The Atmospheres Of Dwa...mentioning

confidence: 99%

Lithium in Stellar Atmospheres: Observations and Theory

Lyubimkov

2016

Astrophysics

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“…In the context of a lithium abundance study, Herbig (1965) noted that lines from the ι Peg secondary were visible at red wavelengths. Lithium abundances for both the primary (Herbig 1965, Conti & Danzinger 1966, Duncan 1981, Lyubimkov et al 1991 and the secondary (Fekel & Tomkin 1983, Lyubimkov et al 1991 indicate the system is very young (∼ 8 × 10 7 yr, Fekel & Tomkin 1983, 1.7 ± 0.8 × 10 8 yr, Lyubimkov et al 1991) and both components are close to the zero-age main sequence. Both components of ι Peg are also believed to have solar-type abundances (Lyubimkov et al 1991).…”

Section: Introductionmentioning

confidence: 95%

The Visual Orbit of ι Pegasi

Boden

Koresko

Belle

et al. 1999

ApJ

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We have determined the visual orbit for the spectroscopic binary ι Pegasi with interferometric visibility data obtained by the Palomar Testbed Interferometer in 1997. ι Pegasi is a double-lined binary system whose minimum masses and spectral typing suggests the possibility of eclipses. Our orbital and component diameter determinations do not favor the eclipse hypothesis: the limb-to-limb separation of the two components is 0.151 ± 0.069 mas at conjunction. Our conclusion that the ι Peg system does not eclipse is supported by high-precision photometric observations. The physical parameters implied by our visual orbit and the spectroscopic orbit of Fekel and Tomkin (1983) are in good agreement with those inferred by other means.In particular, the orbital parallax of the system is determined to be 86.9 ± 1.0 mas, and masses of the two components are determined to be 1.326 ± 0.016 M ⊙ and 0.819 ± 0.009 M ⊙ respectively.

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“…Luck and Bond (1982): This paper is not referenced by Cayrel de Strobel et al (1992). Lyubimkov et al (1991): This paper is not referenced by Cayrel de Strobel et al (1992) because it falls after the cutoff date for their catalog. Magain (1988): The star considered in this paper is HD 76932, for which non-LTE effects may be important.…”

Section: Notes On Literature Sourcesmentioning

confidence: 99%

Analyses of archival data for cool dwarfs. 5: an annotated catalog of averaged values of (Fe/H)

Taylor¹

1994

PASP

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ABSTRACT. At the end of this paper is a catalog containing averaged values of [Fe/H] for 398 FGKIII-V stars. Original sources for the data are given, and users are urged to cite both these sources and the catalog itself in their own work. The balance of the paper contains comments on [Fe/H] sources of interest. Special note is made of [Fe/H] sources which are not cited in the most recent version of the [Fe/H] catalog (Cayrel de Strobel et al. 1992, A&AS, 95, 273).

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Chemical composition of components of the binary lithium star ? Peg

Cited by 6 publications

References 12 publications

Lithium in Stellar Atmospheres: Observations and Theory

Lithium in Stellar Atmospheres: Observations and Theory

The Visual Orbit of ι Pegasi

Analyses of archival data for cool dwarfs. 5: an annotated catalog of averaged values of (Fe/H)

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