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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Astronomy and Space Sciences
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Journal DOI :
The Korean Space Science Society
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Volume & Issues
Volume 18, Issue 3 - Dec 2001
Volume 18, Issue 2 - Nov 2001
Volume 18, Issue 1 - Jun 2001
Selecting the target year
STELLAR POPULATION SYNTHESIS OF THE ELLIPTICAL GALAXY NGC 4649
Journal of Astronomy and Space Sciences, volume 18, issue 3, 2001, Pages 175~190
We investigated population of the elliptical galaxy NGC 4649 using the spectral synthesis technique based on the linear program in the spectral regions between
. We used the spectral data of stars obtained by Gunn & Striker (1983), and the integrated spectrum of NGC 4649 observed by Bertola et al. (1982). Among four models with different main sequence turn-off points, G8-K0V main sequence turn-off model is best fitted to the integrated spectrum of NGC 4649. We also found that super metal rich K giants are needed to describe the absorption lines in the long wavelength regions of integrated spectrum of NGC 4649. The mass to absolute light ratio obtained from the spectral synthesis is ~ 20 similar to those calculated dynamically.
THERRESTRIAL IMPACT CRATERING CHRONOLOGY: A PRELIMINARY ANALYSIS
Moon, Hong-Kyu ; Mi, Byung-Hee ; Fletcher, Andre-B. ; Kim, Bong-Gyu ;
Journal of Astronomy and Space Sciences, volume 18, issue 3, 2001, Pages 191~208
We have recently compiled a database of the properties of 192 impact craters, which supercedes previous compilations. Using our database, the impact structures found in North America, Europe and Australia have been examined; these cratonic areas have been relatively stable for considerably long geological periods, and thus have been best preserved. It is confirmed that there is a close correlation between the geological epoch boundaries, the epochs of mass extinctions, antral the "timing" of impacts. In addition, the terrestrial cumulative flux of objects >20km is found to be
, over the last 120 Myr, which is much smaller than the published values in McEwen et al. (1997) and Shoemaker (1998) (
. For terrestrial impact structures with D> 50 km, the apparent cumulative flux over the last 2450 Myr is ~50 times smaller than the corresponding value for the Moon. If we assume that the Earth and the Moon suffered the same level of bombardment over this time, this would mean that the actual flux of impacting bodies, capable of making craters with D)50 km, was ~ 50 times larger than the apparent flux estimated from the currently known terrestrial records.
EXPOSURE TIME ANALYSIS FOR FAR-ULTRAVIOLET IMAGING SPECTROGRAPH ALL-SKY SURVEY MISSION
Journal of Astronomy and Space Sciences, volume 18, issue 3, 2001, Pages 209~218
Global exposure time distribution through all-sky survey, one of main science missions of KAISTSAT-1, has been simulated. Exposure time distribution has its minimum on the celestial equator and increases with moving to polar regions according to the present mission operation scenario. SAA (South Atlantic Anomaly) and the moon can make further decreases of exposure time around the celestial equator Effects of SAA on all-sky survey exposure time can be compensated with a simple observational scheduling, orbit exchange between orbits allocated to all-sky survey passing through the SAA region and ones allocated to upper atmosphere observations not affected by SAA. It, however, seems that present exposure time distribution is not adequate for the concrete study of the evolution of interstellar medium. A scheme for active time allocation is needed for redistribution of exposure times weighted around the celestial poles, and additional studies on the advanced mission operation and the observational scheduling are also needed.
ERROR BUDGET ANALYSIS OF FIMS OPTICAL SYSTEM
Journal of Astronomy and Space Sciences, volume 18, issue 3, 2001, Pages 219~230
Far-ultraviolet IMaging Spectrograph (FIMS) is under development as the main pay-load of the first Korean science satellite, KAISTSAT-4. An extensive sensitivity and error budget analyses of FIMS optical system have been performed. As an way of estimating aggregate effects of all tolerances, a Monte Carlo simulation is used. The simulation result shows that the optical performance required from the science objectives is achieved within the probability higher than 99.9%.
IMAGING OBSERVATION SYSTEM USING CMOS IMAGE SENSOR
Journal of Astronomy and Space Sciences, volume 18, issue 3, 2001, Pages 231~238
A prototype CMOS (complementary metal oxide semiconductor) imaging system has been built and the possibility of applying to the application to astronomical observations has been investigated. The CCD (charge coupled device) image sensor has been the mainstay of image capture and astronomical imaging for the last 30 years, but CMOS devices have shown rapidly increasing success and have been adapted to many commercial imaging systems . Although the photometric performances and system noise of CMOS sensors are lower than that of CCD image sensors, CMOS Imaging system can be used to obtain general image capture for astronomical applications.
MANUFACTURING AND TEST RESULTS OF OFF-AXIS PARABOLIC CYLINDER MIRROR FOR FIMS
Journal of Astronomy and Space Sciences, volume 18, issue 3, 2001, Pages 239~248
Far-ultraviolet IMaging Spectrograph (FIMS) is the main payload of the first Korean scientific satellite, KAISTSAT-4, which will be launched in 2002. Among the optical parts, parabolic cylinder mirror does not have any heritage from previous astronomical missions, so the manufacturing and testing process itself is a challenging issue. We describe the method of manufacturing and measuring of the off-axis parabolic cylinder mirror and our initial experiments to establish the entire manufacturing process. Using the method, the profile error can meet the specification of
per cm which is closely related with the astronomical performances. In case of the surface roughness, temperature controlled pitch polishing reduces
under 1 nm implying that scattering in the entire spectral range of FIMS is less than 2% of the incident UV light
DEVELOPMENT OF LANGMUIR AND ELECTRON PROBE FOR KSR-III
Journal of Astronomy and Space Sciences, volume 18, issue 3, 2001, Pages 249~256
KARI(Ko.ea Aerospace Research Institute) has measured the ionospheric electron temperature and density over the Korean Peninsular with the Langmuir and Electron Probe(LEP) onboard the Korean Sounding Rocket-II(KSR-II) In 1998. The purpose of LEP is to measure the electron density and temperature profile in the ionosphere. LEP consists of the Langmuir probe(LP) and the Electron temperature Probe(ETP) which are widely used for the measurement of the ionospheric plazma environment . We discuss the development of the Langmuir and Electron Probe which will be onboard the KSR-III and some test results in a simulated space plasma environment with the plasma chamber at the ISAS in Japan. These measurements could contribute to the basic study of ionospheric environment which also can be compared with other reference models such as IRI and PIM.