• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권1호
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• pp.39.3-39.3
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• 2009

• 한국인쇄학회:학술대회논문집
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• 한국인쇄학회 1998년도 추계 논문 발표회 논문집
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• pp.31-35
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• 1998

Spectral reflrectance of the object should be measured to predict the color of object under various illuminants. The spectral reflectance can be represented in a multidemensional space. Generally we can obtain only three-channel data from input device such as CCD camera, color scanner etc. The estimation from three dimensional to multidimension can be achieved using principal components of spectral reflectance. In this paper, A method to predict the spectral reflectance of skin color taken by 3-channel input device is discribed. To confirm this method, we simulate color represent under various illuminants about yellow, white and colored women face.

• 천문학회보
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• 제38권1호
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• pp.62.1-62.1
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• 2013

The Cassini/Visual Infrared Mapping Spectrometer (VIMS) observed the sun through the atmosphere of Titan, and provided vertically-resolved 63 spectra from 49 km to 987 km for the 1 - 5 micron range (Bellucci, 2008). Bellucci et al. (2009) analyzed selected spectral ranges where the band absorptions of $CH_4$ and CO are strong by constructing synthetic spectra including $CH_4$ and CO lines, but without including haze absorptions in their synthetic spectra. Kim et al. (2011) and Sim et al. (2013) were able to extract detailed spectral features of fundamental (Dv = 1) and overtone (Dv = 2) bands of the haze from the VIMS spectra by excluding the adjacent influences of strong $CH_4$ absorptions using a radiative transfer program, which includes effects of absorption and emission of lines of these molecules, and absorption and scattering of haze particles. In this presentation, we extend our detailed analyses to other remaining wavelengths in order to provide the spectral characteristics of the Titanian haze for the entire 1 - 5 micron range and to identify any additional haze spectral features and an unidentified feature near 4.3 microns reported by Bellucci et al. (2009).

• 천문학회보
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• 제41권1호
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• pp.76.2-76.2
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• 2016

We present near-infrared (0.8 - 1.8 microns) spectra of 63 bright (J_mag < 10) stars observed with Low Resolution Spectrometer (LRS) onboard the rocket-borne Cosmic Infrared Background Experiment (CIBER). Two Micron All Sky Survey (2MASS) photometry information is used to find cross-matched stars after reduction and extraction of the spectra. We identify the spectral types of observed stars by comparing with spectral templates from the Infrared Telescope Facility (IRTF) library. All the observed spectra are consistent with late F to M stellar spectral types, and we identify various infrared absorption lines. As our observations are performed above the Earth's atmosphere, our spectra are free from telluric contamination. Including HST/NICMOS and Cassini/VIMS, the spectral coverage has rarely been achieved in space, and the methods developed here can inform statistical studies with future low-resolution spectral measurements such as GAIA photometric and radial velocity spectrometer.

• 천문학회보
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• 제41권1호
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• pp.58.2-58.2
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• 2016

The NISS (Near-infrared Imaging Spectrometer for Star formation history) onboard NEXTSat-1 is the near-infrared instrument optimized to the first small satellite of NEXTSat series. The capability of both imaging and low spectral resolution spectroscopy with the Field of View of $2{\times}2deg.$ in the near-infrared range from 0.9 to $3.8{\mu}m$ is a unique function of the NISS. The major scientific mission is to study the cosmic star formation history in local and distant universe. The Flight Model of the NISS is being developed and tested. After an integration into NEXTSat-1, it will be tested under the space environment. The NISS will be launched in 2017 and it will be operated during 2 years. As an extension of the NISS, SPEHREx (Spectro-Photometer for the History of the Universe Epoch of Reionization, and Ices Explorer) is the NASA SMEX (SMall EXploration) mission proposed together with KASI (PI Institute: Caltech). It will perform an all-sky near-infrared spectral survey to probe the origin of our Universe; explore the origin and evolution of galaxies, and explore whether planets around other stars could harbor life. The SPHEREx is designed to have wider FoV of $3.5{\times}7deg.$ as well as wider spectral range from 0.7 to $4.8{\mu}m$. After passing the first selection process, SPHEREx is under the Phase-A study. The final selection will be made in the end of 2016. Here, we report the current status of the NISS and SPHEREx missions.

• Journal of Astronomy and Space Sciences
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• 제18권2호
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• pp.95-100
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• 2001

We have presented an ab initio model of the $2{mu}m$ spectral features of $(H_2)_2$ based on the far-infrared models of McKellar & Schaefer (1991). We have shown that the intensity variations of the $2{mu}m;(H_2)_2$ features depend on the ortho/para ratios of $H_2$ We have discussed the applicability of the variations to the atmospheres of the giant planets for the derivations of the ortho/para ratios. The signal to noise ratios of currently available spectra of the giant planets are not sufficient enough to derive accurate ortho/para ratios of these planets. Observations with longer exposure times and larger telescope apertures are required to obtain better spectra for the derivations of the ortho/para ratios of $H_2$ in the atmospheres of the giant planets.

• 천문학회보
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• 제43권1호
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• pp.48.2-48.2
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• 2018

SPHEREx is expected to provide us with the opportunity of unbiased sampling of small Solar System objects along with near-infrared ($0.75-5.0{\mu}m$) spectroscopic (R ~ 41) information. The estimated numbers of detections are tens of thousands for asteroids, thousands for Trojans, hundreds for comets, and several for Kuiper Belt Objects, Centaurs and Scattered Disk Objects. Wide spectral range covering many bands from carbon-bearing molecules and ices will enable us to systematically survey the volatile materials throughout the Solar System. SPHEREx will, for the first time, produce the near-infrared spectral map of the zodiacal light to pin-down the relative contributions of various populations of Solar System objects and interstellar dust to the dust grains in the interplanetary space. The study of the zodiacal light is also important to remove the foreground for the EBL (extragalactic background light) study, one of the main topics of the mission.

• 천문학회보
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• 제36권1호
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• pp.69.2-69.2
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• 2011

We present medium resolution spectra in the near-infrared (IR) band 1.4-1.8 microns at a resolving power of R = 5000-10000 of template stars in G, K, and M types with luminosity classes of III observed by the echelle spectrometer, IRCS, at the SUBARU 8.2 m telescope. Identification of lines in the template star spectra has been completed base on the reference of Arcturus spectrum. We measured equivalent width (EW) of the lines, and analyze the trends of EW through the stellar spectral types.

• 천문학회보
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• 제41권2호
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• pp.37.3-37.3
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• 2016

The SPEHREx (Spectro-Photometer for the History of the Universe Epoch of Reionization, and Ices Explorer) is one of the candidates for the Astrophysical Small Explore mission of the NASA proposed together with KASI (PI Institute: Caltech). It will perform an all-sky near-infrared spectral survey to probe the origin of the Universe and water in the planetary systems and to explore the evolution of galaxies. The SPHEREx is designed to cover wide field of view of $3.5{\times}7deg$. as well as wide spectral range from 0.7 to $4.8{\mu}m$ by using four linear variable filters. The SPHEREx is under the Phase-A study to finalize the conceptual design and test plan of the instrument. The international partner, KASI will contribute to the SPHEREx in the hardware as well as the major science cases. The final selection will be made in the early 2017. Here, we report the current status of the SPHEREx mission.

• 천문학회보
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• 제38권2호
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• pp.71.1-71.1
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• 2013

Among quadruples or higher multiplicity stars, only a few binary systems have been discovered. They are important targets to understand the formation and evolution of multiple stellar systems because we can obtain accurate stellar parameters from photometric and spectroscopic studies. We present the observational results of this kind of rare object 1SWASP J093010.78+533859.5, for which the doubly eclipsing feature had been detected previously from the SuperWASP photometric archive. Individual PSF photometry for two objects with a separation of about 1.9 arcsec was performed for the first time in this study. Our time-series photometric data show that the brighter object A is an Algol-type detached eclipsing binary with an orbital period of 1.3 days and the fainter B is a W UMa-type contact eclipsing binary with a period of 0.23 days. Using the high-resolution optical spectra, we obtained well-defined radial velocity variations of the system A. Furthermore, stationary spectral lines were detected and should have originated from the other stellar component, which was confirmed by the third object contribution from the light curve analysis. No spectral feature of the system B was detected, probably due to its faintness. We obtained the binary parameters and the absolute dimensions from each light curve synthesis. The primary and secondary components of the system A have a spectral type of K1 and K5 main sequences, respectively. Two components of system B have nearly the same type of K3 main sequence. Light variations at out of eclipses were appeared in both systems, interpreting as the effect of stellar spots on these late spectral type stars. We estimated the distances to the systems A and B individually. They may have similar distances of about 70 pc and seem to be gravitationally bound with a separation of about 130 AU. In conclusion, we suggest that 1SWASP J093010.78+533859.5 is a quintuple stellar system with a hierarchical structure of a triple system A(ab)c and a binary system B(ab).