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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 88/122
871
- BUDDlNG E.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.205-208
- 1996
- 원문 바로보기
Multi-wavelength observing has been particularly fruitful in cool star research. There have been some well-observed examples, eg AB Dor, though ambiguity remains. This raises issues of data information content and model parameter determinacy, which are examined firstly in an optical context. We then widen the discussion to show how multi-site and multi-wavelength data can be combined to point to better constrained models. Particular cases, involving near-simultaneous radiometry and photometry, are discussed to clarify such modelling.
872
- HIREMATH K. M.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.313-314
- 1996
- 원문 바로보기
Assuming that the solar activity and the solar cycle phenomena may be manifestations of global torsional MHD oscillations, we compute the Alfven wave travel times along the field lines in the five models of magnetic field described in the following text. For all these models, we compute standard deviation and it's ratio to mean Alfvenic wave travel times. The last two models yield the smallest relative bandwidth for the frequencies of the MHD oscillations. However, the last model is the only admissible one which can sustain global Alfvenic oscillations with well defined frequency for the fundamental mode
873
- MINN YOUNG KEY
- Journal of the Korean astronomical society = 천문학회지
- 29, n.1
- pp.75-81
- 1996
- 원문 바로보기
We mapped the <TEX>$^{13}CO$</TEX> line in the dark nebula L134 using the 14-m Taeduck radio telescope with a 57 arcsec beam and one beam spacing. The cloud has a spherical shape with an intensity peak ridge extended from the northwest to the southeast directions. The halfwidth and the radial velocity of the lines peak at the region of the cloud center. The radial velocity decreases from the cloud center towards the north and south directions. The integrated line intensity distributions in the space-velocity plane show some structure and a velocity gradient. The <TEX>$^{13}CO$</TEX> and <TEX>$H_2CO$</TEX> clouds and dark clouds are closely related in space in shape, outer boundary, and intensity peak positions. The <TEX>$^{13}CO$</TEX> integrated line intensity is linearly proportional to the visual extinction.
874
- SAHNI V.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.19-21
- 1996
- 원문 바로보기
We apply topological measures of clustering such as percolation and genus curves (PC & GC) and shape statistics to a set of scale free N-body simulations of large scale structure. Both genus and percolation curves evolve with time reflecting growth of non-Gaussianity in the N-body density field. The amplitude of the genus curve decreases with epoch due to non-linear mode coupling, the decrease being more noticeable for spectra with small scale power. Plotted against the filling factor GC shows very little evolution - a surprising result, since the percolation curve shows significant evolution for the same data. Our results indicate that both PC and GC could be used to discriminate between rival models of structure formation and the analysis of CMB maps. Using shape sensitive statistics we find that there is a strong tendency for objects in our simulations to be filament-like, the degree of filamentarity increasing with epoch.
875
- BESKIN G. M.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.251-252
- 1996
- 원문 바로보기
876
- CANNON RUSSELL
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.367-370
- 1996
- 원문 바로보기
Construction of the 'Two-degree Field' (2dF) instrument on the Anglo-Australian Telescope (AAT) is now virtually complete and commissioning is well underway. The key components are described. Several recent milestones are reported, including the first scientific results. Future prospects and plans are discussed.
877
- LEE YOUNG-WOOK
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.49-51
- 1996
- 원문 바로보기
New population synthesis models, with the effects of metallicity spread and the horizontal-branch (HB) morphology, provide a way to break the well-known age-metallicity degeneracy in the analysis of the integrated light of elliptical galaxies. Our models suggest that the far- UV radiation of these systems is dominated by a minority population of metal-poor, hot HB stars and their post-HB progeny, while the optical radiation is dominated by a metal-rich population. The systematic variation of UV upturn depends on the contribution from metal-poor, hot HB stars and their post-HB progeny, which in turn depends on the ages of old stellar populations in galaxies. Our result implies a prolonged epoch of galaxy formation, in the sense that more massive galaxies (in denser environments) formed first. Our models also suggest that the strenghth of H<TEX>$\beta$</TEX> index is strongly affected by HB stars, and hence previous age estimation without detailed modeling of the HB would underestimate the ages of ellipticals by <TEX>$\~$</TEX>7 Gyr.
878
- WEE SUN-OK
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.181-194
- 1996
- 원문 바로보기
We present a study of the metallicity of the old open cluster NGC 1245 , based on the Washington CCD photometry obtained using the 0.6 m telescope at the Sobaeksan Observatory, Korea. NGC 1245 has been known to be a unique cluster among the known open clusters in the sense that the previous metallicity estimates for this cluster are much larger <TEX>$(by\;\sigma)$</TEX> than the value expected from the radial metallicity gradient of the old open clusters in Our galaxy. We have estimated the metallicity of the cluster red giants using the four color-color diagrams, obtaining a value for the mean metallicity of <TEX>$[Fe/H] = -0.04\pm0.05$</TEX> dex. The total error including the error of the metallicity calibration, 0.15 dex, is 0.16 dex. The metallicity estimate of NGC 1245 we have obtained in this study is smaller than previous estimates, and is consistent with the radial metallicity gradient of the old open clusters, showing that the mean metallicity of NGC 1245 is not abnormally high. The reddening, distance, and age of the cluster have also been derived using the isochrones based on the convective overshooting models: the reddening <TEX>$E(B-V) = 0.28\pm0.03$</TEX>; the distance <TEX>$d = 2.5\pm0.2 kpc$</TEX> (the corresponding galactocentric distance is RGC = 10.7 kpc, and the distance from the galactic plane is z = -0.4 kpc); and the age <TEX>$t = 1.1\pm0.1 Gyrs$</TEX>.
879
- KIM SANG CHUL
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.83-84
- 1996
- 원문 바로보기
880
- SHAMSHIEV FAZILIDDIN T.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.73-74
- 1996
- 원문 바로보기
This paper deals with steady-state gravitational potentials of nonaxisymmetric three dimensional systems which rotate with a constant angular velocity. For these systems a class of potentials with local integrals has been found.