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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 92/122
911
- KIM SUNGSOO S.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.143-144
- 1996
- 원문 바로보기
Two-component models (normal star and degenerate star components) are the simplest realization of clusters with a mass spectrum because the high mass stars quickly evolve off leaving degenerate stars behind, while low mass stars survive for a long time as main-sequence stars. In the present study we examine the post-collapse evolution of globular clusters using two-component Fokker-Planck models that include three-body binary heating. We confirm that a simple parameter <TEX>${\epsilon}{\equiv} (E_{tot}/t_{rh})/(E_c/t_{rc})$</TEX> well describes the occurrence of gravothermal oscillations of two-component clusters. Also, we find that the degree of instability depends on the steepness of the mass function such that clusters with a steeper mass function are less exposed to instability.
912
- MOON YONG-JAE
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.207-215
- 1996
- 원문 바로보기
To derive coronal temperature, electron density and nonthermal velocity, we have analyzed high resolution spectra (e.g., Fe XII 338.3, Fe XII 352.1, Fe XIV 334.2, Fe XIV 353.8, Fe XV 284.2, Fe XV 321.8, Fe XV 327.0, Fe XVI 335.4, and Fe XVI 360.8) taken from AR 6615 by SERTS (Solar Extreme Ultraviolet Rocket Telescope and Spectrograph). Important findings emerging from the present study are as follows: (1) Temperature estimated from Fe XVI 335.4 and Fe XIV, 334.2 is <TEX>$\~2.4\times10^6 K$</TEX> and no systematic difference in temperature is found between the active region and its adjacent quiet region; (2) Mean electron density estimated from Fe XV is <TEX>$\~3\times10^9 cm^{-3}\;and\;\~10^{10} cm^{-3}$</TEX> from Fe XII and Fe XIV; (3) Mean density of the active region is found to be higher than that of the quiet region by a factor of 2; (4) Nonthermal velocity estimated from Fe XV and Fe XVI is <TEX>$20\times25 km\;s^{-l}$</TEX> which decreases with increasing ionization temperatures. This supports the notion that the nonthermal velocity declines outwards above the transition region.
913
- CHUN MOO-YOUNG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.137-156
- 1996
- 원문 바로보기
NGC 6716 is an intermediate-age open cluster in Sagittarius. In this paper, we present the new UBV CCD photometry of the stars in the cluster, which is deeper than previous ones. From the color-color diagram and the color-magnitude diagram, we derived a reddening <TEX>$E_{B- V} = 0.17\pm0.03$</TEX> and a distance modulus of the cluster, <TEX>$(V - Mv)_o = 9.2\pm0.1$</TEX>. An age of the cluster is estimated as <TEX>$8\pm10^7 yrs$</TEX> from the latest isochrone. Luminosity function and mass function of the cluster are derived. The gradient of the mass function of bright stars is a bit steep, <TEX>$\Gamma = -1.85\pm0.05$</TEX>, and there is no distinct bump and dip in the mass function.
914
- LEE SANG-GAK
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.171-179
- 1996
- 원문 바로보기
We have obtained the J K images of the central region of the globular cluster M3 (NGC5272), using the <TEX>$256\pm256$</TEX> InSb array. We present JK photometry of bright red giant branch stars in the central <TEX>$2'.2\pm2'.2$</TEX> region of M3. The infrared color-magnitude diagrams are presented. The comparison of the red giant branch of M3 with that of M13 confirms that both globular clusters have similar metal abundances.
915
- KHOSROSHAHI H. G.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.277-278
- 1996
- 원문 바로보기
In attempts to detect gravitational waves, the response of some celestial systems such as the earth[l] or binary systems[2] to such waves have been investigated. Following this line of thought, here we study the possibility of excitation of the oscillation modes of a polytropic star by gravitational radiation and calculate the relevant absorption cross sections.
916
- LIN GUAN-QING
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.401-402
- 1996
- 원문 바로보기
917
- TOVMASSIAN H. M.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.149-150
- 1996
- 원문 바로보기
The results of observations of a dozen OB stellar associations made with the ultraviolet space telescope Glazar is presented.
918
- Qu Z. Q.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.307-308
- 1996
- 원문 바로보기
919
- Hul F. X.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.53-54
- 1996
- 원문 바로보기
Based on the database of 128 disk galaxies (66 SO, 62 S and Irr) mailnly compiled from Kent and Gunn (1982) and Doi et a1.(1995) which is complete down to m < 15.6 mag within a radius of <TEX>$3^{\circ}$</TEX>, the orientation of spin vectors of disk galaxies of the Coma cluster has been analyzed. The results confirm the morphological dependence of the orientation of disk galaxies found from the analsis of the Virgo cluster. Common features of orientation of disk galaxies of both clusters are outlined.
920
- WANG JIA LONG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.217-221
- 1996
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We have examined morphological change and movements of individual sunspots within a sunspot group in association with a large solar flare activity (3B/X1.5) appeared on 13 May 1981. For this purpose we measured distance among spots during the period before and after the flare activity and estimated the average velocity of their movement. Our main results are as follows: (1) The longitudinal displacement among sunspots are generally greater than the latitudinal displacement. (2) During the period the spots moved with an average velocity of 1.2 km/s in longitude and 0.86 km/s in latitude. (3) The most notable change took place in the central part placed between the two ribbons of the flare.