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1984년 ~ 2025년까지 1,255 건의 한국우주과학회지를 계간으로 확인하실 수 있습니다.
- The Korean Space Science Society (The Korean Astronomical Society)
- 계간 (Quarterly)
- ISSN : 1225-052x (ISSN : 1225-052x)
1225-052x
- DB구축현황 : 1,255건 (DB Construction : 1,255 Articles)
총 게시글 1,255건
페이지 50/126
491
- Song, Young-Joo
- Journal of astronomy and space sciences
- 27, n.2
- pp.97-106
- 2010
- 원문 바로보기
To prepare for a Korean lunar orbiter mission, a precise lunar orbit propagator; Yonsei precise lunar orbit propagator (YSPLOP) is developed. In the propagator, accelerations due to the Moon's non-spherical gravity, the point masses of the Earth, Moon, Sun, Mars, Jupiter and also, solar radiation pressures can be included. The developed propagator's performance is validated and propagation errors between YSPOLP and STK/Astrogator are found to have about maximum 4-m, in along-track direction during 30 days (Earth's time) of propagation. Also, it is found that the lifetime of a lunar polar orbiter is strongly affected by the different degrees and orders of the lunar gravity model, by a third body's gravitational attractions (especially the Earth), and by the different orbital inclinations. The reliable lifetime of circular lunar polar orbiter at about 100 km altitude is estimated to have about 160 days (Earth's time). However, to estimate the reasonable lifetime of circular lunar polar orbiter at about 100 km altitude, it is strongly recommended to consider at least <TEX>$50\;{\times}\;50$</TEX> degrees and orders of the lunar gravity field. The results provided in this paper are expected to make further progress in the design fields of Korea's lunar orbiter missions.
492
- Lee, Woo-Ju
- 韓國宇宙科學會誌 = Journal of astronomy & space sciences
- 27, n.1
- pp.11-20
- 2010
- 원문 바로보기
This paper designs a data link between a Lunar Orbiter (LO) and an Earth Station (ES), and analyzes the downlink performance of a space communications system for lunar exploration, conforming to the recommendations by the Consultative Committee for Space Data Systems (CCSDS). The results provided in the paper can be useful references for the design of reliable communication link for the Korean lunar exploration in the near future.
493
- Lee, Sung-Ho
- Journal of astronomy and space sciences
- 27, n.4
- pp.309-318
- 2010
- 원문 바로보기
We introduce a technical approach for reducing three-dimensional infrared (IR) spectroscopic data generated by integral field spectroscopy or slit-scanning observations. The first part of data reduction using IRAF presents a guideline for processing spectral images from long-slit IR spectroscopy. Multichannel image reconstruction, Image Analysis and Display (MIRIAD) is used in the later part to construct and analyze the data cubes which contain spatial and kinematic information of the objects. This technic has been applied to a sample data set of diffuse 2.1218 <TEX>${\mu}m$</TEX> <TEX>$H_2$</TEX> 1-0 S(1) emission features observed by slit-scanning around Sgr A East in the Galactic center. Details of image processing for the high-dispersion infrared data are described to suggest a sequence of contamination cleaning and distortion correction. Practical solutions for handling data cubes are presented for survey observations with various configurations of slit positioning.
494
- Jeong, Jang-Hae
- Journal of astronomy and space sciences
- 27, n.2
- pp.81-88
- 2010
- 원문 바로보기
A total of 583 observations (193 in <TEX>${\Delta}b$</TEX>, 190 in <TEX>${\Delta}v$</TEX>, 200 in <TEX>${\Delta}r$</TEX>) for V523 Cas was made on 9 nights from September to December in 2008 using the 100 cm telescope with 2K CCD camera of the Chungbuk National University Observatory. With our data BVR light curves were constructed and 9 times of minimum light were determined. We also obtained physical parameters of the V523 Cas system by analysis of the BVR light curves using the Wilson-Devinney code.
495
- Chang, Heon-Young
- 韓國宇宙科學會誌 = Journal of astronomy & space sciences
- 27, n.1
- pp.1-10
- 2010
- 원문 바로보기
The distance distribution in our planetary system has been a controversial matter. Two kinds of important issues on Titius-Bode's relation have been discussed up to now: one is if there is a simple mathematical relation between distances of natural bodies orbiting a central body, and the other is if there is any physical basis for such a relation. We have examined, by applying it to exo-planetary systems, whether Titius-Bode's relation is exclusively applicable to our solar system. We study, with the <TEX>$X^2$</TEX> test, the distribution of period ratios of two planets in multiple planet systems by comparing it with that derived from not only Titius-Bode's relation but also other forms of it. The <TEX>$X^2$</TEX> value between the distribution of the orbital period derived from Titius-Bode's relation and that observed in our Solar system is 12.28 (dof=18) with high probability, i.e., 83.3 %. The value of <TEX>$X^2$</TEX> and probability resulted from Titius-Bode's relation and observed exo-planetary systems are 21.38 (dof=26) and 72.2 %, respectively. Modified forms we adopted seem also to agree with the planetary system as favorably as Titius-Bode's relation does. As a result, one cannot rule out the possibility that the distribution of the ratio of orbiting periods in multiple planet systems is consistent with that derived from Titius-Bode's relation. Having speculated Titius-Bode's relation could be valid in exo-planetary systems, we tentatively conclude it is unlikely that Titius-Bode's relation explains the distance distribution in our planetary system due to chance. Finally, we point out implications of our finding.
496
- Lee, Chung-Uk
- Journal of astronomy and space sciences
- 27, n.4
- pp.289-307
- 2010
- 원문 바로보기
We developed a photometric pipeline to be used for a wide field survey. This pipeline employs the difference image analysis (DIA) method appropriate for the photometry of star dense field such as the Galactic bulge. To verify the performance of pipeline, the observed dataset of the open cluster M11 was re-processed. One hundred seventy eight variable stars were newly discovered by analyzing the light curves of which photometric accuracy was improved through the DIA. The total number of variable stars in the M11 observation region is 335, including 157 variable stars discovered by previous studies. We present the catalogue and light curves for the 178 variable stars. This study shows that the photometric pipeline using the DIA is very useful in the detection of variable stars in a cluster.
497
- Cho, Joon-Sik
- Journal of astronomy and space sciences
- 27, n.3
- pp.189-194
- 2010
- 원문 바로보기
In this paper we have investigated latitudinal variations of the poleward boundary of the nightside auroral oval when the magnetosphere is hit by an enhanced solar wind dynamic pressure front. We used precipitating particle data obtained from Defense Meteorological Satellite Program satellites to identify the locations of the boundary before and after enhanced pressure impacts. The boundary locations are represented by a parameter called 'b5e'. After performing the analysis for a number of events, we found that the basic effect of the solar wind pressure increase impact is often (but not always) to move the poleward boundary of the nightside auroral oval poleward. However, this effect can be often modified by other factors, such as simultaneous variations of the interplanetary magnetic field with a pressure increase, and thus the boundary response is not necessarily a poleward shift in many cases. We demonstrate this with specific examples, and discuss other possible complicating factors.
498
- Kim, Sang-Hyuk
- Journal of astronomy and space sciences
- 27, n.2
- pp.161-172
- 2010
- 원문 바로보기
In this paper, we investigate the sundials made by the Kang Family of Jinju in the later period of the Joseon dynasty in terms of their characteristics, functions and the manufacturing technique. One of the characteristics of these sundials is that the value of polar height (i.e., the latitude of Seoul), the name of manufacturer, 24 seasonal subdivisions and so forth are written on the surface. In particular, polar height is expressed as '<TEX>$37^{\circ}$</TEX> 39' 15'' in all 12 sundials examined in this study. To investigate the manufacturing technology in terms of astronomy, we analyze the positions of gnomon and of the lines corresponding to 24 seasonal subdivisions (season lines) and to each hour (hour lines). To verify the accuracy of the positions, we use a planar projection method. That is, we obtain 2D images of the sundials using a camera or scanner, and compare these with astronomical calculations for the positions of gnomon and season/hour lines. We believe that this method will be very useful for the study of sundials preserved elsewhere.
499
- Hwang, Jung-A
- 韓國宇宙科學會誌 = Journal of astronomy & space sciences
- 27, n.1
- pp.43-54
- 2010
- 원문 바로보기
This study was performed by the policy research project of Ministry of Land, Transport and Maritime Affairs, which title is 'Developing safety standards and management of space radiation on the polar route'. In this research, total six experiments were performed using Korean commercial flights (B747). Three of those are on the polar route and the other three are on the north pacific route. Space radiation exposure measured on the polar route is the average 84.7 uSv. The simulation result using CARI-6M program gives 84.9 uSv, which is very similar to measured value. For the departure flight using the north pacific route, the measured space radiation is the average 74.4 uSv. It seems that is not so different to use the polar route or not for the return flight because the higher latitude effect causing the increase of space radiation is compensated by the shortened flight time effect causing decreasing space radiation exposure.
500
- Chung, Moon-Hee
- Journal of astronomy and space sciences
- 27, n.3
- pp.239-244
- 2010
- 원문 바로보기
A simulation for the design of a <TEX>$90^{\circ}$</TEX> differential phase shifter aimed toward Korean VLBI Network (KVN) 129 GHz band polarizer is described in this paper. A dual-circular polarizer for KVN 129 GHz band consists of a <TEX>$90^{\circ}$</TEX> differential phase shifter and an orthomode transducer. The differential phase shifter is made up of a square waveguide with two opposite walls loaded with corrugations. Three-dimensional electromagnetic simulation has been performed to predict the <TEX>$90^{\circ}$</TEX> differential phase shifter's characteristics. The simulation for the differential phase shifter shows that the phase shift is <TEX>$90^{\circ}{\pm}3.3^{\circ}$</TEX> across 108-160 GHz and the return losses of two orthogonal modes are better than -30 dB within the design frequency band. According to the simulation results the calculated performance is quite encouraging for KVN 129 GHz band application.