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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 96/122
951
- YANAGISAWA KENSHl
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.75-76
- 1996
- 원문 바로보기
We have started multi-color imaging program of nearby galaxies since last year and present preliminary result here. We selected 12 nearby galaxies classfied from E to Sab type and observed in BVRIJHK' bands. Photomtric parameters such as isophotal diameter, axial ratio, isophotal magnitude were measured and observed colors were compared with theoritical model. We find a standard evolution model agrees well with observed results.
952
- KOZAI YOSHIHIDE
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.351-354
- 1996
- 원문 바로보기
In this paper it is explained how most of asteroids can avoid very close approach to Jupiter, to the earth for earth orbit crossing asteroids, and to Neptune for Kuiper-belt asteroids by mechanisms which work also for Neptune-Pluto system. In fact the mutual distance of the planets cannot become very small as the critical argument librates around <TEX>$180^{\circ}$</TEX> because of 2:3 mean motion resonance and the argument of perihelion of Pluto librates around <TEX>$90^{\circ}$</TEX>. And it is found that among nearly 40 Kuiper-belt asteroids discovered in recent years <TEX>$40\%$</TEX> have orbits similar to Pluto. For main-belt asteroids the distribution with respect to the semi-major axes has peculiar characteristics and the author tries to explain how their peaks and gaps are created. It is also found that <TEX>$30\%$</TEX> of 80 earth orbit crossing asteroids which have minimum perihelion distances less than 1.04AU have no chance to collide with the earth. Still <TEX>$30\%$</TEX> of them have a few probability to collide with the earth as they have dynamical characteristics of short-periodic comets.
953
- CHITRE S. M.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.31-33
- 1996
- 원문 바로보기
The role of gravitational lenses as valuable tools for astrophysics and cosmology is highlighted.
954
- TSIOPA O. A.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.215-216
- 1996
- 원문 바로보기
The wind-formed features observed in the early SNe spectra type II and Ia give an evidence of the existence of an ellipsoidal shell formed by the stellar wind prior to the explosion. Such non-spherical shell can occur not only at scales of parsec (the case of SN 1987 A progenitor), but at the scales of 1000 times less. Such shells can be the result of the radial pulsation. The prolate multi-shell structures are interpreted as a result of a pulsation processes with recurrent wind ejections with velocity increasing.
955
- PARK SEOK JAE
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.97-98
- 1996
- 원문 바로보기
Variability of active galactic nuclei is now a well-known phenomenon. This remains to be fully explained by a theoretical model of the central engine. Time scales of AGN variability seem to range continuously from hours up to months. The short time scale variability must be related to the phenomena on the event horizon of the black hole, while the long one to those in the accretion disk or surrounding matter. Based on the axisymmetric, nonstationary model of the central engine, we discuss theoretical considerations on the variability of active galactic nucleus.
956
- YANG SUNG-CHUL
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.141-142
- 1996
- 원문 바로보기
957
- UMEDA HIDEYUKI
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.23-24
- 1996
- 원문 바로보기
We reexamined CDM texture large-scale structure (LSS) formation model. We confirmed that texture model is consistent with 4-year COBE data both in an open and a critical matter density (<TEX>${\Omega}_0$</TEX> = 1) universes, and then obtained normalization for density perturbation power spectrum. We next compare the power spectrum with LSS observation data. Contrary to the previous literature, we found that texture model matches with these data in an open universe no better than in an <TEX>${\Omega}_0$</TEX> = 1 universe. We also found that the model is more likely to fit these data in a cosmological constant dominated (<TEX>$\Lambda-$</TEX>) universe.
958
- CHEN JIAN-SHENG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.407-407
- 1996
- 원문 바로보기
959
- ANN HONG-BAE
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.255-268
- 1996
- 원문 바로보기
We present VR CCD photometry and long-slit spectroscopy of a late type spiral galaxy NGC 7678. The grey scale images and isophotal maps illustrate the presence of a weak bar from which spiral arms emerge. There are many HII regions along the spiral arms, but bright giant HII regions are more concentrated in the massive southern arm. The bright compact nucleus of NGC 7678 is bluer than bulge and bar. The spectral features of the nucleus and HII regoins are very similar but the nuclear spectra shows higher <TEX>$[NII]{\lambda}6583/H_\alpha$</TEX> than those of the HII regions. The nucleus of NGC 7678 seems to be intermediate type between HII region nulcei and LINERs by the ratio of <TEX>$[NII]{\lambda}6583/H_\alpha$</TEX>, but it is more likely to be HII region-like nucleus if we consider the <TEX>$[NII]{\lambda}6716,6731/H_\alpha$</TEX> together. The star formation rate is estimated to be about <TEX>$0.2 M_\bigodot\;yr^{-1}$</TEX> based on the <TEX>$H_\alpha$</TEX> flux.
960
- KIM T.-S.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.39-40
- 1996
- 원문 바로보기
Using the Keck 10 m telescope data with the HIRES spectrograph, we analyzed the evolution of Lyman<TEX>$\alpha$</TEX> forest clouds at z > 2 down to the HI column density <TEX>$10^{12.8}cm^{-2}$</TEX>. The number density per unit column density does not change with redshifts at lower HI cloumn density (<TEX>$N_{HI} < 10^{14}cm^{-2}$</TEX>), while the forest clouds at higher column density disappear rapidly. The cutoff b value, the thermal temperature indicator, increases as redshift decreases. The correlation strength seems to be stronger as redshift decreases.