모달창 닫기
- 홈으로 이동
1968년 ~ 2024년까지 1,211 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 : 1,211건 (DB Construction : 1,211 Articles)
총 게시글 1,211건
페이지 110/122
1091
- Lee, See-Woo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 21, n.2
- pp.182-182
- 1988
- 원문 바로보기
1092
- Hong, Seung-Soo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 21, n.2
- pp.155-171
- 1988
- 원문 바로보기
We have examined how sensitively the extinction value determined by the method of star-count depends on such factors as the plate limit, the size of counting reseau, the non-linearity in the number distribution of stars with magnitude, and the angular resolution demanded by the given problem. We let the Poisson distribution portray the statistical nature of the countings, and chose the region containing the globule Barnard 361 as an example field. Uncertainties due to various combinations of the factors are presented in graphic forms: (1) Dynamic range in the extinction measurements is evaluated as a function of reseau size for varying plate limits. (2) Statistical errors involved in the star-count are analized in terms of the signal-to-noise ratio, the plate limit and the reseau size. (3) Systematic error due to the non-linearity in the number distribution are thoroughly analized. (4) Finally, a methodology is presented for correcting the systematic error in the observed radial density gradient. These graphs are meant to be used in selecting proper size of the reseau and in estimating errors inherent to the star-count analysis.
1093
- Lee, See-Woo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 21, n.1
- pp.37-55
- 1988
- 원문 바로보기
Combining the luminosity functions of main sequence stars in 3 associations and 22 open clusters, the initial luminosity function and mass function for these clusters are derived. For stars of m > <TEX>$0.6m_{\odot}$</TEX>, they are well consistent with those for the field stars.
1094
- Lee, Sang-Gak
- 天文學會誌 = The journal of the Korean Astronomical Society
- 21, n.2
- pp.173-181
- 1988
- 원문 바로보기
The usual method of classification for metal poor stars is based on the normal standard stars. In this study, we show that among the sample of stars classified by this method, a systematic bias in the observed classes of metal weakness is found and, also that this method is not appropriate for classification of metal poor stars, by showing that the spectral line dependences on the temperature and pressure in the extreme metal poor stars are different from those in the normal standard stars. Therefore, we suggest that the 3-dimensional classification system, like 2-dimensional MK system, is necessary for an accurate classification of metal poor stars.
1095
- Chun, Mun-Suk
- 天文學會誌 = The journal of the Korean Astronomical Society
- 21, n.1
- pp.67-77
- 1988
- 원문 바로보기
Nine giant star's spectra in NGC 3201 were obtained using the image tube in Sutherland. From the analysis of these spectra we found the increase of Ca I and CH abundances with decreasing the radial distnace, but CN, Ca II and Fe abundances do not show this. Dependence of the calculated parameters seems to exist among CN, Ca I, Ca II and CH abundances.
1096
- Kim, Kwang-Tae
- 天文學會誌 = The journal of the Korean Astronomical Society
- 21, n.2
- pp.133-153
- 1988
- 원문 바로보기
Linear polarization has been measured for fifteen extragalactic radio sources in the field of supernova remnant S 147. These observations were made at 4885, 4835, 1665, 1515, 1465, and 1385 MHz using the Very Large Array, primarily to determine unambiguous Rotation Measures (RM) of the sources. This yields a total of 11 new RM sources. Comparisons of a sample of sources which are seen through S 147 were made with sources located farther away. The result tentatively indicates that the distribution of the rotation measure of the former population is broadened, with more than a 85% level of confidence. This constitutes evidence that there is a SNR contribution to rotation measure in sources seen through the SNR. Limits on this RM contribution are statistically at 30 < | RM | < 70 rad <TEX>$m^{-2}$</TEX> with a 85% statistical level of confidence. These result imply the magnetic field in the rim of S 147 has strength 10 microguass if the electron density is <TEX>$1\;cm^{-3}$</TEX>.
1097
- Kim, Kwang-Tae
- 天文學會誌 = The journal of the Korean Astronomical Society
- 21, n.2
- pp.117-132
- 1988
- 원문 바로보기
Multi-frequency polarization observations of Abell 695 are reported here. The brightest radio source 0838+325, which was previously classified as a wide angled head-tail radio source, is, in the present observations, resolved into two separable sources, a head-tail source 0838+325 AB and a diffuse one 0838+325C. The radio-tail shows high degree of linear polarization(<TEX>${\sim}50$</TEX>-25%) along the radio-tail, suggesting that the interaction with its surrounding intracluster medium (ICM) is not highly turbulent. With the present data, thermal particle densities at the locations of these sources are estimated to be n > <TEX>$10^{-5}\;cm^{-3}$</TEX>.
1098
- Lee, See-Woo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 21, n.1
- pp.1-36
- 1988
- 원문 바로보기
The temperature calibration of stars by photometric parameters and spectral type is discussed, using the catalogue data of Cayrel de Strobel et al. (1985) and Morel et al. (1976). The H-R diagrams and the mass-luminosity relation of stars in this catalogue are presented in the [log(L/M)-log <TEX>$T_e$</TEX>]-and [<TEX>$M_{bol}$</TEX>-log(L/M)]-planes, respectively, discussing the age of main sequence (MS) stars and giant stars. The age-metallicity relation of the nearby stars suggests the initial rapid enrichment of metal abundance.
1099
- Shin, Jun-Ho
- 天文學會誌 = The journal of the Korean Astronomical Society
- 20, n.1
- pp.1-26
- 1987
- 원문 바로보기
By inverting the brightness integral for the dust-scattered continuum, we have determined how the dust grains are distributed inside the Orion nebula. The scattering characteristics of the Orion dust at a given wavelength is kept constant within the nebula, and the geometry of the nebula is assumed to have a hemispherical shape. The resulting radial distance dependence of the distribution of dust number density, <TEX>$N_d(r)$</TEX>, shows that the dust grains are depleted at the central region of the Orion nebula and concentrated in the region <TEX>$5'{\sim}6'$</TEX> away from the Trapezium stars. The scattering characteristics of the Orion dust are of moderately forward throwing nature, and the Orion dust has low values of albedo.
1100
- Sung, Hwan-Kyung
- 天文學會誌 = The journal of the Korean Astronomical Society
- 20, n.2
- pp.63-94
- 1987
- 원문 바로보기
Using many homogeneous data of DDO and UBV colors for all luminosity classes and physical quantities known from spectroscopic observations, new calibration schemes with DDO photometric parameters are presented for metal abundance, effective temperature and surface gravity of stars. And an intrinsic color relation is derived for the reddening estimate.