간행물
천문학회지 KCI 등재 SCOPUS Journal of The Korean Astronomical Society
- 발행기관 한국천문학회
- 자료유형 학술지
- 간기 반년간
- ISSN 1225-4614 (Print)2288-890X (Online)
- 수록기간 1968 ~ 2024
- 주제분류 자연과학 > 천문학 자연과학 분류의 다른 간행물
- 십진분류KDC 440DDC 520
권호리스트/논문검색
제11권 제1호 (1978년 12월) 5건
1.
1978.12
구독 인증기관 무료, 개인회원 유료
The four dimensional classification of globular dusters with the parameters, Z, Y, age and HB type is presented defining two new parameters. ( B − V ) 1 / 2 a n d S 3 / 2 which are shown to be tightly correlated with Kinman's spectral types and the helium abundances obtained from the R-method, respectively. The Z- and Y- abundances are derived from ( B − V ) 1 / 2 a n d S 3 / 2 , respectively, and the latter parameters determine the age class of clusters with help of Dickens' HB type, which is a function of Z. Y and age. For the examined forty two globular clusters the computed range at Z and Y are 1.5×10 -4 ≤ Z ≤ 4.5×10 -2 and 0.23 ≤ Y ≤ 0.41. The age difference between the oldest (HB type 1) and the youngest (HB type 7) clusters is roughly estimated to be 2 − 4 × 10 9 years. Using these four parameters the known anomalous C-M diagrams seem to be reasonably interpreted without taking into account some complicate parameters such as unusually overabundant heavy elements, mass loss and mass spread, etc. The four dimensional scheme strongly suggests the slow successive collapses of the proto-Galaxy rather than a single fast collapse, and by this slow collapse model the inversion of chemical abundance gradient in the Galaxy can be explained. It is also shown that the clump position along the RGB near the HB level removes down to the fainter magnitude as the Z(Y)- abundance increases (decreases).
6,900원
2.
1978.12
구독 인증기관 무료, 개인회원 유료
Although Serkowski used a single value K=1.15 in representing all the observed interstellar linear polarization curves by his empirical relation p ( λ ) / P m a x =exp (-K 1 n 2 ( λ m a x / λ ) ), where p m a x is the maximum polarization at wavelength λ m a x , we have noticed a meaningful variation in K from observations of 72 stars. By comparing K's with P m a x / E B − V a n d w i t h λ m a x , we have examined how the shape of the polarization curve is related with the degree of grain alignment on one hand, and with grain sizes on the other. We have shown that correlations between K, P m a x / E B − V a n d w i t h λ m a x , are consistent with the idea of Davis-Greenstein mechanism for grain alignment.
4,000원
3.
1978.12
구독 인증기관 무료, 개인회원 유료
A hydrostatic model atmosphere of a typical umbral core is constructed on the basis of both Na I D 2 line profile and umbral core-to disk continuum intensity ratio. The observations were obtained by Mullan and Wyller with photoelectric means over the range from 4000 |AA a n d 6500 |AA . The computed line profile of Na I D 2 and the emergent continuum intensity distribution are compared with the observations. The temperature of umbral cores is found to be lower by 300 ˚ K t o 500 ˚ K than that of their ambient umbral region. The detailed physical structure of a working model of umbral cores is proposed.
4,000원
4.
1978.12
구독 인증기관 무료, 개인회원 유료
Twelve Chih was sasigned to each day in the old Chinese calendar. This paper clarifres the relations between 12 Chih and the diurnal motion of Big Dipper or the clock, and it shows the long term table and formula for the dayly assignment of 12 Chih in the calendar.
4,000원
5.
1978.12
구독 인증기관 무료, 개인회원 유료
An extensive molecular equilibrium calculation has been performed under sunspot conditions in order to resolve the current dispute on the presence of C 2 lines in the spectrum of sunspots. Equilibrium abundance of C 2 has been computed under the conditions of umbral cores, umbrae and the normal photosphere. As the results, it is found that the umbral cores yield unfavorable environment for C 2 formation. It is concluded that C 2 molecular lines are not likely tn be observed in the spectrum of sunspots.
3,000원
