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천문학논총 KCI 등재 Publications of the Korean Astronomical Society

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Volume 1 (1984년 12월) 5

1.
1984.12 구독 인증기관 무료, 개인회원 유료
Under the context of Stein's linear theory of stellar models, the luminosity-effective temperature relationship is derived for contracting pre-main sequence stars which are losing mass, according to the empirical formula, given by Reimers (1975). The effects of mass loss on their evolution are investigated by calculating evolutionary tracks of 1. 1.5M⊙ 1.5M⊙ , 5M⊙ 5M⊙ , and 10M⊙ 10M⊙ , stars. Our calculations reveal that the effects of mass loss show up in the radiative equilibrium stage of the evolution. It is found that an increase of mass loss rate leads to delay the onset of radiative equilibrium, thus resulting in under-luminous main sequence stars. It is also noted that the mass loss prolongs the pre-main sequence life time. Detailed results of the calculations are discussed.
4,000원
2.
1984.12 구독 인증기관 무료, 개인회원 유료
Using King's model, we derived the dynamical masses of six globular clusters. The masses of clusters were calculated from the dynamical length parameters combined with the central velocity dispersion. The dynamical masses are all in the range from 2.5×105M⊙ 2.5×105M⊙ to 1.4×105M⊙ 1.4×105M⊙ . The (M/Lv)⊙ (M/Lv)⊙ , values lie between 1.0 and 1.2, which are typical for galactic clusters.
3,000원
3.
1984.12 구독 인증기관 무료, 개인회원 유료
New empirical relations between stellar CaII emission and rotation or age are derived by analyzing Wilson's CaII flux measurements (1968, 1978) of lower main sequence stars, and then we correlate them with their age and rotation rate. It is found that stellar chromospheric emission decays smoothly with age as a star slows down rotationally, establishing that both the emission level and rotation rate decrease with the square root of age.
4,000원
4.
1984.12 구독 인증기관 무료, 개인회원 유료
The origin of five small satellites (1980 S1, 1980 S3, 1980 S26, 1980 S27 and 1980 S28) and F-ring of Saturn which were recently discovered inside the orbit of Mimas, is proposed in terms of the resonant effects by external satellites in the Saturnian primordial extended ring. From the calculations of resonance locations and strengths, the following conclusion could be derived. Assuming that present two objects 1980 S1 and 1980 S3 were originally a single object 1980 S1+S3, 1980 S1+S3 had been formed due to Enceladus' 2/1 resonance and 1980 S26 due to Mimas' 3/2 resonance at first and then 1980 S28. 1980 S27 and F-ring were formed in the next due to 1980 S1+S3's 8/7, 9/8 and 10/9 resonances, respectively.
5,100원
5.
1984.12 구독 인증기관 무료, 개인회원 유료
For F,G,K stars, their photometric data and metallicity, [Fe/H] are collected and their correlations between δ δ (U-B) and [Fe/H] for each spectral group are examined, using a reference sequence which is defined by the stars in Woolley's catalogue and other reference sequences. Detailed examination shows that the reference sequence by Woolley's catalogue appears to be properly defined for the calculation of δ δ (U-B) of population I stars in the solar neighborhood. It is suggested that accuracies of metallicities derived from δ δ (U-B) can be improved if we derive the correlations between [Fe/H] and δ δ (U-B) from the stars in each spectral group.
4,900원