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1968년 ~ 2023년까지 1,187 건의 한국천문학회지를 격월간 확인하실 수 있습니다.
- The Korean Astronomical Society (The Korean Astronomical Society)
- 계간 (Quarterly)
- ISSN : 1225-4614 (ISSN : 1225-4614)
1225-4614
- DB구축현황 : 1,187건 (DB Construction : 1,187 Articles)
총 게시글 1,187건
페이지 115/119
1141
- Hong, Seung-Soo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 12, n.1
- pp.27-34
- 1979
- 원문 바로보기
Temperature history of very small interstellar dust particles is followed under diffuse interstellar radiation. Because of extremely small thermal capacities of these grains with sizes ranging from a few tens to hundred Angstroms in radii, they are to experience strong fluctuations in temperature whenever they are hit by interstellar ultraviolet photons. Fluctuating temperature can inhibit these smaller component of interstellar dust from growing into core-mantle particles of submicron sizes by continuously evaporating atoms and molecules adsorbed on their surface. This is interpreted as a possible physical reason for the bimodal nature in grain size distribution. A brief discussion is also given to the far infrared emission properties of such small grains in diffuse interstellar dust clouds.
1142
- Lee, See-Woo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 11, n.1
- pp.1-30
- 1978
- 원문 바로보기
The four dimensional classification of globular dusters with the parameters, Z, Y, age and HB type is presented defining two new parameters. <TEX>$(B-V)_{1/2}\;and\;S_{3/2}$</TEX> 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 <TEX>$(B-V)_{1/2}\;and\;S_{3/2}$</TEX>, 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 <TEX>$1.5{\times}10^{-4}{\leq}Z{\leq}4.5{\times}10^{-2}\;and\;0.23</TEX><TEX><</TEX><TEX>Y{\leq}0.41$</TEX>. The age difference between the oldest (HB type 1) and the youngest (HB type 7) clusters is roughly estimated to be <TEX>$2-4{\times}10^9$</TEX> 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).
1143
- Yun, Hong-Sik
- 天文學會誌 = The journal of the Korean Astronomical Society
- 11, n.1
- pp.37-46
- 1978
- 원문 바로보기
A hydrostatic model atmosphere of a typical umbral core is constructed on the basis of both Na I <TEX>$D_2$</TEX> 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 <TEX>$4000{\AA}\;and\;6500{\AA}$</TEX>. The computed line profile of Na I <TEX>$D_2$</TEX> and the emergent continuum intensity distribution are compared with the observations. The temperature of umbral cores is found to be lower by <TEX>$300^{\circ}K\;to\;500^{\circ}K$</TEX> than that of their ambient umbral region. The detailed physical structure of a working model of umbral cores is proposed.
1144
- 이은성
- 天文學會誌 = The journal of the Korean Astronomical Society
- 11, n.1
- pp.47-54
- 1978
- 원문 바로보기
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.
1145
- Beebe, Reta Fay
- 天文學會誌 = The journal of the Korean Astronomical Society
- 11, n.1
- pp.55-58
- 1978
- 원문 바로보기
An extensive molecular equilibrium calculation has been performed under sunspot conditions in order to resolve the current dispute on the presence of <TEX>$C_2$</TEX> lines in the spectrum of sunspots. Equilibrium abundance of <TEX>$C_2$</TEX> 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 <TEX>$C_2$</TEX> formation. It is concluded that <TEX>$C_2$</TEX> molecular lines are not likely tn be observed in the spectrum of sunspots.
1146
- Hong, Seung-Soo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 11, n.1
- pp.31-36
- 1978
- 원문 바로보기
Although Serkowski used a single value K=1.15 in representing all the observed interstellar linear polarization curves by his empirical relation <TEX>$p({\lambda})/P_{max}$</TEX>=exp (-K <TEX>$1n^2({\lambda}_{max}/{\lambda})$</TEX>), where <TEX>$p_{max}$</TEX> is the maximum polarization at wavelength <TEX>${\lambda}_{max}$</TEX>, we have noticed a meaningful variation in K from observations of 72 stars. By comparing K's with <TEX>$P_{max}/E_{B-V}\;and\;with\;{\lambda}_{max}$</TEX>, 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, <TEX>$P_{max}/E_{B-V}\;and\;with\;{\lambda}_{max}$</TEX>, are consistent with the idea of Davis-Greenstein mechanism for grain alignment.
1147
- 조순화
- 天文學會誌 = The journal of the Korean Astronomical Society
- 10, n.1
- pp.3-12
- 1977
- 원문 바로보기
<TEX>$Str\ddot{o}mgren$</TEX>-system colors for 23 OV stars compiled by Crawford have been compared with colors calculated by Mihalas from non-LTE model atmospheres. In this way, effective temperatures of these stars have been determined and plotted against spectral type, <TEX>$c_1$</TEX> (u-b), (b-y), (U-B), and (B-V). Within the accuracy of the observations, effective temperatures derived from the photometry for these 23 main-sequence stars are found to be in good agreement with Contiis spectroscopical temperatures.
1148
- 오규동
- 天文學會誌 = The journal of the Korean Astronomical Society
- 10, n.1
- pp.23-30
- 1977
- 원문 바로보기
식변광성 WZ And에 대한 지금까지 관측 발표된 극심시각을 수집하여 이 별의 수기 변화를 분석하였다. 0-C도에 의한 이 별의 주변화는 JD2418000과 JD243500근처에서 각각 dp/p=<TEX>$+4.24{\times}10^{-6}$</TEX>과 dp/p=<TEX>$-2.46{\times}10^{-6}$</TEX>의 돌발적인 주기 변화를 보였다. WZ And의 주기변화의 모습을 분석하기 위하여 Biermann and Hall(1973)이 제시한 접촉 연섬계로부터 <TEX>$7.42{\times}10^6M_0$</TEX>가 온도가 높은 별(hotter component)로 교환됨을 산출하였다. 이러한 량의 질량교환으로 인한 주기감소를 계산하였다. 질량교환 모델에 의한 JD243500이후의 이론적인 주기로 <TEX>$0^d.69565848$</TEX>를 얻었으며, 관측에 의한 0-C도로부터 얻은 주기 <TEX>$0^d.69566034$</TEX>과 매우 잘 일치하고 있다. 한편, WZ And의 질량비에 의하면 이 별은 온도가 더 높은 별이 Roche lobe를 채우고 있음을 보여주며 이러한 WZ And는 Paczynski(1970)의 접촉연성계의 접화단계에서 Stage II에 있는 별이다.
1149
- 이은성
- 天文學會誌 = The journal of the Korean Astronomical Society
- 10, n.1
- pp.13-22
- 1977
- 원문 바로보기
일진(日辰)의 중국역(中國曆)에서 매우 긴요하게 사용(使用)되고 있다. 이 논문(論文)에서는 (1) 103태양년(太陽年)을 지나면 절기(節氣)에 대하여 일진(日辰)이 되돌아오고, (2) 124년(年)을 지나면 음력일(陰曆日)에 대하여 일진(日辰)이 복소되는 것을 보여주었고, 이와 아울러 (3) 62태양(太陽)마다 월(月)의 대소(大小)가 되풀어 된 것은 것을 발견하였다. 이것들은 태음태양력(太陰太陽曆)에서 메톤 주기에 못하지 않는 흥미 있는 주기(週期)이다.
1150
- Lee, See-Woo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 10, n.1
- pp.31-38
- 1977
- 원문 바로보기
To reduce the instrumental and calibration errors in the photoelectric photometry as much as possible it is necessary to select the optimum photocell voltage and energy attenaution and to observe as many standard stars as possible over the wide range of color, spectral type and air mass.