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 111/122
1101
- Lee, Jeong-Woo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 20, n.2
- pp.95-95
- 1987
- 원문 바로보기
1102
- Ann, Hong-Sik
- 天文學會誌 = The journal of the Korean Astronomical Society
- 20, n.2
- pp.49-62
- 1987
- 원문 바로보기
Using the detailed two-dimensional surface photometry of 39 galaxies, the observed profiles are decomposed into spheroid, disk and bar components simultaneously. From the analyses of decomposition parameters, the correlations among the three components are investigated to find the global property of barred galaxies. And the lens and ring components, and spiral arm patterns are also examined with Hubble type and decomposition parameters.
1103
- 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.
1104
- Ann, Hong-Bae
- 天文學會誌 = The journal of the Korean Astronomical Society
- 19, n.2
- pp.69-89
- 1986
- 원문 바로보기
The global morphology and geometric parameters of 39 barred galaxies are investigated, by using isophote map and isodensity tracings obtained from detailed surface photometry with the Kiso V-band plates. The observed results are as follows: i) There is no strong indication that the ratio of bar length to disk size is correlated with Hubble type, except that the largest bars appear in the SBb galaxies. ii) The mean value of axial ratios of bars is <TEX>$2.0{\pm}0.4$</TEX> and there is a trend that early type galaxies have smaller axial ratios than late type galaxies. iii) About 15% of early type barred galaxies(Sb0-SBb) have triaxial bulges.
1105
- Park, Yong-Sun
- 天文學會誌 = The journal of the Korean Astronomical Society
- 19, n.1
- pp.15-31
- 1986
- 원문 바로보기
We have analyzed Gray's observed mean line bisectors of FS, G0, G2, and G5 normal dwarf stars and interpreted them by computing theoretical line bisectors based on a two stream model. A set of perturbed models has been derived, and their detailed structures on temperature fluctuations and velocity fields are presented as a function of depth, which account for the observed bisectors. From the present study, it is found that the degree of stellar convective overshootings and temperature fluctuations in the upper atmospheres increases towards earlier spectral types. The convection cell size inferred from these models is found to increase also with the advancing earlier type. We demonstrated the usefulness of line bisector analysis as a diagnostic probe for stellar convection.
1106
- Lee, See-Woo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 19, n.2
- pp.51-62
- 1986
- 원문 바로보기
The Wielen dip over the ragne of 6 < <TEX>$M_{\upsilon}$</TEX> < 9 in the luminosity function (LF) for the solar neighborhood stars could be explained by the combination of two different IMFs which yields the age of 13 billion years of the solar neighborhood. This smaller age than the Galactic age, 15 billion years indicates the slow collapse model of the Galaxy, solving the G-dwarf problem. Two different IMFs suggest two different mechanisms for star formation in the solar neighborhood.
1107
- Chang, Kyong-Ae
- 天文學會誌 = The journal of the Korean Astronomical Society
- 19, n.1
- pp.11-14
- 1986
- 원문 바로보기
It is shown in this paper that the astigmatic property of single gravitational lens in static bounded gravitational field can be retained, if n-gravitating body as a whole acts simultaneously as gravitational lens.
1108
- Park, Nam-Kyu
- 天文學會誌 = The journal of the Korean Astronomical Society
- 19, n.1
- pp.1-9
- 1986
- 원문 바로보기
We present a method for deriving most optimal filter system by which the accuracy of derived physical quantities can be maximized. Using Kurucz(1978)'s model atmospheres, an optimal four filter system for F and G dwarfs is suggested, for which mean wavelengths are located at <TEX>$3400{\AA}$</TEX>, <TEX>$3850{\AA}$</TEX>, <TEX>$4190{\AA}$</TEX>, and <TEX>$4600{\AA}$</TEX> with half-bandwidth of <TEX>$200{\AA}$</TEX>. It is found that 35, 38 and 42 filters of the DDO system and the <TEX>$Str{\ddot{o}}mgren$</TEX> u and <TEX>$\nu$</TEX> filters are close to those of the most optimal system.
1109
- Yoo, Chin-Woo
- 天文學會誌 = The journal of the Korean Astronomical Society
- 19, n.1
- pp.33-49
- 1986
- 원문 바로보기
Radial distribution of internal density has been determined for thirteen subclouds in the three giant molecular cloud complexes accompanying Mon OB1, Mon OB2 and CMa OB1 associations, We modeled their radial density structures with the density distribution of isothermal gas spheres. Most of the subclouds, nine out of the thirteen, are well described by isothermal spheres of single component; while the rest four require an additional component. Total mass and potential energy of each subcloud are also derived from the radial density structure; thermal energy and internal velocity dispersion required for sustaining the density structure are deduced from the isothermal gas model. Our derived masses of the clouds are comparable to the values determined by Blitz (1978) under LTE assumption. This agreement suggests that the correction factor for non-LTE effect on mass-estimate is not far from unity. The ratio of the gravitational potential energy to the kinetic energy of thermal motion is as large as 250; hence the thermal motion alone cannot support these clouds against the gravity. Being supported by turbulence motion with velocities of six to seven times the thermal velocity, the clouds of one-component type seem to be in equilibrium with the gravity; while the clouds of two-component type are likely to be in the stage of gravitational collapse.
1110
- Park, Chang-Bum
- 天文學會誌 = The journal of the Korean Astronomical Society
- 19, n.2
- pp.91-107
- 1986
- 원문 바로보기
Making use of our extended version of <TEX>$\ddot{O}pik's$</TEX> convection theory, we have calculated magnetic cycle periods of the sun and late type stars by using Parker's dynamo theory, where we have included the non-linear effect. We presented a relationship between the computed cycle period and spectral type to analyze observed magnetic activities of the late type stars and long-term luminosity variations. It is found that (1) the stellar magentic-cycle period increases towards the later spectral type, (2) the rapid rotation facilitates the activity-related luminosity variation of stars later than about K5, (3) differential rotation plays a critical role in determining the magnetic activity-cycle period, and (4) the non-local effect should be taken into account in order to understand the observed long-term luminosity variations.