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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 87/122
861
- 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.
862
- CHOI MINHO
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.195-196
- 1996
- 원문 바로보기
We observed CO J = 2 <TEX>$\to$</TEX> 1 and J = 3 <TEX>$\to$</TEX> 2 lines toward several star formation regions with extremely high velocity (EHV) outflows: W3 IRS5, W28 A2, GL2591, S140, and Cepheus A. The full width of the wings are 90-235 km <TEX>$s^{-1}$</TEX>. Some wings show clear break of slope in the line profile implying that the nature of the EHV outflow is different from that of the high velocity outflow. We suggest that the EHV CO wing emission is tracing CO molecules in the stellar wind or jet which drives the high velocity outflow.
863
- XIE R. X.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.331-332
- 1996
- 원문 바로보기
We present 3 rare subtypes of the FFSs observed with high temporal resolution at 4-frequency (1.42, 2.13, 2.84 and 4.2G GHz). The various FFSs occurred during the main and post-flare phase can demonstrate that coronal nonthermal electron acceleration/injection may go through the whole development process of flares, and deduce that there may exist the re-forming of loop-like structures in the post-flare phase, and the complex multi-type magnetic structures in corona.
864
- CHOE SEUNG-URN
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.93-105
- 1996
- 원문 바로보기
We have solved the radiative transfer problem using a Sobolev approximation with an escape probability method in case of the supersonic expansion of a stellar envelope to an ambient medium. The radiation from the expanding envelope turns out to produce a P-Cygni type profile. In order to investigate the morphology of the theoretical P-Cygni type profile, we have treated <TEX>$V_\infty,\;V_{sto},\;\beta$</TEX> (parameters for the velocity field), it and E(parameter for collisional effect) as model parameters. We have investigated that the velocity field and the mass loss rate affect the shapes of the P-Cygni type profiles most effectively. The secondarily important factors are <TEX>$V_\infty,\;V_{sto}$</TEX>. The collisional effect tends to make the total flux increased but not so much in magnitude. We have infered some physical parameters of 68 Cyg, HD24912, and <TEX>$\xi$</TEX> persei such as <TEX>$V_\infty,\;M$</TEX> from the model calculation, which shows a good agreenment with the observational results.
865
- TIERSCH H.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.59-60
- 1996
- 원문 바로보기
866
- SUN AIQUN
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.397-398
- 1996
- 원문 바로보기
Large field spectrographs are severely influenced by atmospheric refraction. LAMOST is a large field multi-object spectroscopy telescope with <TEX>$5^{\circ}$</TEX> field of view, f/5 focus ratio and 20m focal length. There will be 4000 fibers simultaneous on it's <TEX>$\phi$</TEX>1.75m focal plane. Here we discuss the atmospheric refraction effects on LAMOST in two hands. One is the effect of differential refraction across the field, another is the effect of atmospheric dispersion. According to the calculation, we find that: 1. The largest deviation from center within the field is 4.;32' during a 1.5-hour integration at <TEX>$80^{\circ}$</TEX> declination. 2. The directions of deviation are complex, so the deviations can't be decreased by rotating the field. We also give out the atmospheric dispersions.
867
- KIM BONG GYU
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.193-194
- 1996
- 원문 바로보기
A large scale <TEX>$^{13}CO$</TEX>(J=1-0) survey was made for CMa OB1/R1 region in <TEX>$220^{\circ}{\le}{\iota}{\le}230^{\circ}$</TEX> and <TEX>$-10^{\circ}{\le}b{\le}10^{\circ}$</TEX> with a 8' spacing by using the 4 m radio telescope of Nagoya University. 34 isolated clouds were identified in this survey. Among them, two clouds were firstly identified by us. The observed LSR velocity indicate that almost of the all clouds are located in the Local arm, except two extreme velocity. The mass spectrum of the clouds in the Local arm is best fitted by a power-law index of 1.6.
868
- KOMAROVA V. N.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.217-218
- 1996
- 원문 바로보기
The results of the Crab pulsar observations with the photometrical MANIA (Multichannel Analysis of Nanosecond Intensity Alterations) complex at the 6-m telescope are presented. More than 12 millions photons in UBVR-bands simultaneously with time resolution of <TEX>$10^{-7}s$</TEX> were detected. Using the original software for search for optical pulsar period, we obtained the light curves of the object with time resolution of about 3.3 <TEX>${\mu}s$</TEX>. Their detailed analysis gives the spectral change during pulse and subpulse, the shape of the pulse peaks, which are plateaus (with the duration of about 50<TEX>${\mu}s$</TEX> for the main pulse), limits for an amplitude of fine temporal (stochastic and regular) structure of pulse and sub pulse and the interpulse space intensity. The results of CCD-spectroscopy of the Crab pulsar show that its summarized spectrum is flat. There are no lines, neither emission nor absorbtion ones. Upper limit for line intensity or depth is <TEX>$3.5\%$</TEX> with the confidence probability of <TEX>$95\%$</TEX>.
869
- REY Soo-JONG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.11-14
- 1996
- 원문 바로보기
Super-inflation driven by dilaton/moduli kinetic energy is naturally realized in compactified string theory. Discussed are selected topics of recent development in string inflationary cosmology: kinematics of super-inflation, graceful exit triggered by quantum back-reaction, and classical and quantum power spectra of density and metric perturbations.
870
- SANGUANSAK N.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.169-170
- 1996
- 원문 바로보기
In the past, it. was very difficult to distinguish thermal and non-thermal emission. Broadbent et a1. (1989) has developed a new technique with the help of the IRAS 60 micron emission. The distribution of non-thermal or synchrotron emission in the Galactic disk has been modeled from the 408 MHz all sky survey of Haslam et a1. (1982) after removal of the thermal component.. At. 408 MHz, t.here is very little absorption in the interstellar medium and the distribution along the line-of-sight. is inferred mainly from its presumed relationship to other tracers of spiral structure via a. number of fitted parameters. But. at lower frequencies, free-free absorption becomes important and can give some direct. information on the line of sight. distribution. We have modeled the thermal electron density according to the spiral arm models and the distribution of ionized hydrogen in the Galactic plane by Lockman (1976) and Cersosimo et. al. (1989) and have made predictions to compare with the surveys of Dwarakanath et al. (1990) at. 34.5 MHz and .Jones and Finlay (1974) at 29.9 MHz. The result confirms that the absorption model of the synchrotron emissivity in the Galactic plane is broadly corrected and illustrates the potential of the absorption technique.