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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 89/122
881
- KIM YONGGI
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.235-236
- 1996
- 원문 바로보기
Using a phenomenological model for the accretion onto the magnetic white dwarf, we calclliated some optical line profiles from the magnetosphere of such systems. Line profiles of these systems seem to be produced in the magnetosphere of the compact star due to the reemission of X-ray produced near the stellar surface. Some results of our new calculation and the analysis of these results will be presented. Our results show that the model used here can reproduce the observed optical line profiles and open the possiblity to determine the parameters of individual systems.
882
- CHA SEUNG-HOON
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.253-254
- 1996
- 원문 바로보기
To understand the dynamical structures of stellar wind bubble, one and two-dimensional calculations has been performed. Using FCT Code with cooling effects and assuming constant mass loss rate and ambient medium density, we could divide stellar winds into the regime of slow and fast winds. The slow wind driven bubble shows initially radiative and becomes partially radiative bubble in which shocked stellar wind zone is still adiabatic. In contrast., the fast wind driven bubble shows initially fully adiabatic and becomes adiabatic bubbles with radiative outer shell. We also determine analytically the onset of thin-shell formation time in case of fast wind driven bubble with power-law energy injection and ambient density structure. We solve the line transfer problem with numerical results in order to calculate line profile of [OIII] forbidden line.
883
- YUN H. S.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.339-340
- 1996
- 원문 바로보기
In the present study we examine physical characteristics of a thin and rigid magnetic flux tube with a steady flow inside, which is embedded vertically upward in the solar atmosphere. We found from this study that (1) The downward material flow gives rise to a dominant heating in the flux tube which works with the conductive heating in the same direction. However, the upflow flow creates a dominant cooling which works against the conductive heating, resulting in a steeper temperature gradient with a shallower transition region. (2) Since the thickness of the transition region determines the material content in the transition region, a broader transition region of the downflow tube produces a larger differential measure.
884
- LAI S. P.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.327-328
- 1996
- 원문 바로보기
885
- STALIN C. S.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.341-342
- 1996
- 원문 바로보기
We present here the solar LOG GF values obtained using the Liege solar at las and the standard solar photospheric models for the spectral lines in the wavelength range <TEX>${\lambda}{\lambda}$</TEX> 6209 - 6273 <TEX>${\AA}$</TEX>. These log gf values shall be used to interpret a high resolution spectra of the star <TEX>$\gamma$</TEX> Draconics.
886
- KIM SEUNG-LEE
- Journal of the Korean astronomical society = 천문학회지
- 29, n.1
- pp.31-41
- 1996
- 원문 바로보기
We present results of time-series CCD photometry for 178 stars in the young open cluster M29 (=NGC6913). Total 1036 V-band CCD frames were collected for five nights between August 12 and September 13, 1994. The photometric precision is about 7.6 mmag for 9th-10th mag stars in M29 with exposure times of 30 seconds. From the dispersion diagram and the light curves, one detached eclipsing binary (HD194378) and two suspected variables are newly discovered. <TEX>$A\;\gamma\;Cas$</TEX> type variable, V1322 Cyg, which has been known as a member of M29, did not show any light variations during the period of present observations, indicating that it passed the steady phase without the eruption during our observing runs.
887
- YUAN Q. R.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.55-56
- 1996
- 원문 바로보기
In order to investigate the spatial orientation of the spin vectors of galaxies in the Virgo cluster, we carried out a detailed identification of all the certain and possible member disk galaxies with four UK Schmidt Telescope (UKST) III a-j direct plates digitized by the Automated Plate Measuring System (APM). As a result, a relatively large and complete database with no selection effect of the member galaxies has been established. We provide the APM measured values of the position angle (P.A.) and diameters at the isophotal level of 24.5 <TEX>$m_j / arcsec^2$</TEX>. Based on this newly generated database, an initial study on the spatial orientation of the spin vectors of galaxies in the Virgo cluster is shown.
888
- CHEN ROSIE CHANG-HUI
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.135-136
- 1996
- 원문 바로보기
We present a new photometric study of the globular cluster NGC288 in Stromgren u, v, b, y, and H<TEX>$\beta$</TEX> system. This cluster is known to have an intermediate metallicity but its color-magnitude diagram has a pure blue horizontal branch, which is a signature of metal poor stellar population. We compare our dataset with Bergbusch's (1993) in both field size and CMD to see whether different photometry system would determine the same physical parameters of a cluster. Demarque and Yi's isochrones (1996, private communication) were applied to Bergbusch's dataset, and we obtained distance modulus of (m - M) = 14.9 <TEX>$\pm$</TEX> 0.2, color excess of E(B - V) = 0.03, and age of 1.5<TEX>$\pm$</TEX>3 Gyr. Vandenberg's (1985) isochrones for Stromgren system were also applied to Bergbusch's and our data. We find that the isochrone fits to different photometric systems give rather in consist ant solutions. The source of this discrepancy may become clear when the Demarque and Yi's isochrones for Johnson system are converted to those of Stromgren system. We note that Kurucz model atmospheres provide a useful ground for this conversion work as well as theoretical study of Stromgren characteristics of globular cluster stars.
889
- SUBRAMANIAN K.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.155-158
- 1996
- 원문 바로보기
Magnetic fields correlated on several kiloparsec scales are seen in spiral galaxies. Their origin could be due to the winding up of a primordial cosmological field or due to amplification of a small seed field by a turbulent galactic dynamo. Both options have difficulties: There is no known battery mechanism for producing the required primordial field. Equally the turbulent dynamo may self destruct before being able to produce the large scale field, due to excess generation of small scale power. The current status of these difficulties is discussed. The resolution could depend on the nature of the saturated field produced by the small scale dynamo. We argue that the small scale fields do not fill most of the volume of the fluid and instead concentrate into intermittent ropes, with their peak value of order equipartition fields, and radii much smaller than their lengths. In this case these fields neither drain significant energy from the turbulence nor convert eddy motion of the turbulence on the outer scale to wave like motion. This preserves the diffusive effects needed for the large scale dynamo operation.
890
- ZHANG X.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.199-200
- 1996
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