• Title/Summary/Keyword: stars:atmosphere

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A Study on the Sun-Moon-Stars(日月星辰) appeared in Huang Ti Nei Chin(『黃帝內經』) (『황제내경(黃帝內經)』에 나타난 일월성진(日月星辰)에 관(關)한 연구(硏究))

  • Park, Chan-Yeong;Kim, Gi-Uk;Park, Hyeon-Guk
    • The Journal of Dong Guk Oriental Medicine
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    • v.5
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    • pp.281-306
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    • 1996
  • A study on the effect of the Sun-Moon-Stars(日月星辰) in Huang Ti Nei Ching("黃帝內經") on the formation of the Yunqi theory(運氣理論) have revealed following conclusions. 1. There was a record of Stars(星辰) written by Gabgol-Character(甲骨文字) in the Yin(殷) Dynasty. But the very first documentary records of Stars(星辰) is Shu Jing("書經"). Ancient astronomy had the tendency of astrology of combined with theory of the Five Elements(五行) and finally effects the theory of formation of Huang Ti Nei Ching("黃帝內經"). 2. Shu Jing("書經") said that Junrak(錢樂) made an Armillary sphere(運天儀) in the Sung(宋) Dynasty. And in the Jin(秦) and the Han(漢) Dynasty, they already observed the stars. The Sunkiokhyung(璿機玉衡) which is machinery of star-observing, became to be called an Armillary sphere (運天儀) by the pass of times. 3. As of the theory of the Cosmos-structure(宇宙-構造論) in Ohanunhangdaeron("五運行大論"), Guiyugu(鬼兒區) announced the Hypothesis of Covering Heaven(蓋天說) but Kibak(岐伯) supported the Hypothesis of chaosheven's(蓋天說) and in the theory of atmosphere(大氣論) in Ohanunhangdaeron("五運行大論") said that the earth was in Great Empty(太虛) and it was floating in the universe by the Great Chi(大氣). 4. The knowledge about the Five stars(五星) in Huang Ti Nei Ching("黃帝內經") is presented in the section of Gemgwejineonron("金?眞言論"), Gigoupyondaeron("氣交變大論"), Youkwonjeonggidaeron("六元正紀大論").ln the method of identifying the Five stars(五星) presented the criteria of the brightness, the altitude, the colours and the orbit etc. 5. The jupiter which has twelve year's revolution cycle was the basis of determination on the Twelve constellation(12辰), the Twelve field of heaven(12次), the Twelve Houses in the ecliptic(黃道 12宮), the Twelve Earth's Branches(12支) and the Twelve fields of Earth(12分野) and also it became the origin of the duodecimals(12進法). 6. The saturn having about twenty-eight year's revolution cycle became the criterion in identifying the Twenty Eight Constellations(28宿) which was used as the coordinates of the Celestial sphere (天球). 7. By the Percussional movement(歲差運動), the position of polaris and the Vernal-Antumal equinox(春秋分点) were shifted. Therefore the ancient the Heaven Gate-Earth Door(天門-地戶) changed from the position of Sil-Byuk(室壁), Yik-Jin(翼軫). And the precisional movements brought about the concept of the WunHoyYunSe(元會運世) that is a method of dividing a period. Also the precisional movement gave three dimension(三次元) foundation interpreted the Sixty JiaZi (六十甲子) which is revolving through sixty years uniformally. 8. The Hypothesis of the Nine Houses and Eight Winds(九宮八風論) which is one field of the astrology of ancient polaris-nine Houses divination plate(太一九宮占盤) brought about the concept of deficiency and excess and the concept of the Wind Vice(風邪). In the Calendar System(曆法) presented in Huang Ti Nei Ching("黃帝內經") the tropical year of the Sun-Moon-Stars(日月星辰) and the revolution and the rotation of the earth give explanations the changes of Yin-Yang(陰陽) by the use of the ten Celestial branches(十干) and the twelve Earth branches(十二支).

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Attitude Scenarios of Star Observation for Image Validation of Remote Sensing Satellite (영상검정을 위한 지구관측위성의 별 관측 자세 시나리오 생성 기법)

  • Yu, Ji-Woong;Park, Sang-Young;Lee, Dong-Han
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.9
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    • pp.807-817
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    • 2012
  • An optical payload needs to be validated its image performance after launched into orbit. The image performance was validated by observing star because ground site contains uncertainties caused by atmosphere, time of the year, and weather. Time Delayed and Integration(TDI) technique, which is mostly used to observe the ground, is going to be used to observe the selected stars. A satellite attitude scenario was also developed to observe the selected stars. The scenario is created to enable TDI to operate. Rotation angles of optical payload are determined in order for the selected stars to properly be passed at a desired angular velocity about rotation axis. The result of this research can be utilized to validate the quality of optical payload of a satellite in orbit. In addition, a quaternion for pointing selected stars is calculated minimizing the path from a given arbitrary attitude of satellite.

Identification and spectral analysis of the CIBER/LRS detected stars

  • Kim, MinGyu;Matsumoto, T.;Lee, Hyung Mok;Arai, T.;Battle, J.;Bock, J.;Brown, S.;Cooray, A.;Hristov, V.;Keating, B.;Korngut, P.;Lee, Dae-Hee;Levenson, L.R.;Lykke, K.;Mason, P.;Matsuura, S.;Nam, U.W.;Renbarger, T.;Smith, A.;Sullivan, I.;Wada, T.;Jeong, Woong-Seob;Zemcov, M.
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.141.1-141.1
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    • 2012
  • CIBER (Cosmic Infrared Background ExpeRiment) is a sounding-rocket borne experiment which is designed to find the evidence of the First stars (Pop.III stars) in the universe. They are expected to be formed between the recombination era at z ~ 1100 and the most distant quasar (z ~ 8). They have never been directly detected due to its faintness so far, but can be observed as a background radiation at around $1{\mu}m$ which is called the Cosmic Near-Infrared Background (CNB). The CIBER is successfully launched on July 10, 2010 at White Sands Missile Range, New Mexico, USA. It consists of three kinds of instruments. One of them is a LRS (Low Resolution Spectrometer) which is a refractive telescope of 5.5 cm aperture with spectral resolution of 20 ~ 30 and wavelength coverage of 0.7 to $2.0{\mu}m$ to measure the spectrum of the CNB. Since LRS detects not only CNB but also stellar components, we can study their spectral features with the broad band advantage especially at around $1{\mu}m$ which is difficult at ground observations because of the atmospheric absorption by water vapor. I identified around 300 stars from observed six fields. If we can classify their spectral types with SED fitting, we can study their physical conditions of the stellar atmosphere as well as making a stellar catalogue of continuous stellar spectrum.

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A CODE FOR CALCULATING STATIC MODEL STELLAR ATMOSPHERES

  • Nouh, M.I.
    • Journal of The Korean Astronomical Society
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    • v.42 no.3
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    • pp.47-54
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    • 2009
  • In this paper we present an independent FORTRAN code for calculating LTE-plane-parallel model atmospheres. The transfer equation has been solved using Avrett and Loeser method. It is shown that, using an approximate non-gray temperature distribution together with the iteration factors method (Simonneau and Crivellari) for correcting the temperature distribution reduce the number of iteration required to achieve the condition of radiative equilibrium. Preliminary results for pure helium model atmospheres are presented.

IGRINS Spectral Library

  • Park, Sunkyung;Lee, Jeong-Eun;Kang, Wonseok;Lee, Sang-Gak;Chun, Moo-Young;Kim, Kang-Min;Yuk, In-Soo;Lee, Jae-Joon;Mace, Gregory N.;Kim, Hwihyun;Kaplan, Kyle F.;Jaffe, Daniel T.
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.43.3-43.3
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    • 2016
  • We present a library of high-resolution (R~45,000) and high signal-to-noise ratio ($S/N{\geq}200$) near-infrared spectra of 147 standard stars. High quality spectra were obtained with Immersion GRating INfrared Spectrograph (IGRINS) covering the full range of H ($1.496-1.795{\mu}m$) and K ($2.080-2.460{\mu}m$) bands. The targets are mainly selected as MK standard stars which have well-defined spectral types and luminosity classes, and cover a wide range of effective temperatures and surface gravities. The spectra were corrected for telluric absorption lines and absolute flux calibrated using Two Micron All Sky Survey (2MASS) photometry. We find new spectral indices in H and K bands and provide their EWs. We describe empirical relations between the measured EWs and stellar atmosphere parameters such as effective temperature and surface gravity.

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Mediating effect of social support on the relationship between viewing sensational videos of idol stars and adolescent sexual openness (아이돌 스타를 촬영한 선정적인 영상물 시청과 청소년 성개방성과의 관계에서 사회적 지지의 매개효과)

  • Kim, Seok Hwan
    • The Journal of Korean Society for School & Community Health Education
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    • v.23 no.4
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    • pp.41-48
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    • 2022
  • Objectives: This study aims to investigate the mediating effect of social support on the relationship between the viewing of sensational videos of idol stars through the mass media and the sexual openness of adolescents. Methods: This study used the 'Study on countermeasures against sexual commodification of adolescents through mass media in the smart era' conducted by the 'Korea Youth Policy Institute' in 2014 for the entire country as the main data. Variables consisted of socio-demographic characteristics of study subjects, video viewing, social support, and sexual openness. For data analysis, SPSS ver 23.0 program was used. Results: As a result of comparing the averages, male students (20.40) had higher sexual openness than female students (18.67), and high school students (20.27) had higher sexual openness than middle school students (18.05) at school level. By grade level, sexual openness increased from the first year of middle school (17.47) to the third year of high school (20.82) (p<0.001). In order to verify the mediating effect of video viewing on the effect of adolescent social support on sexual openness, 3-step mediated regression analysis and Sobel test were conducted. As a result, video viewing had a significant effect on sexual openness through social support (p<0.001). Conclusion: Rather than obscuring the environment of mass media unconditionally, creating an atmosphere according to the tendency of realistic social support and reinforcing emotional education will help prevent the adverse effects of reckless sexualization of adolescents.

The Barium Star HD204075: Iron Abundance and the Absence of Evidence for Accretion

  • Jeong, Yeuncheol;Yushchenko, Alexander;Gopka, Vira;Yushchenko, Volodymyr;Rittipruk, Pakakaew;Jeong, Kyung Sook;Demessinova, Aizat
    • Journal of Astronomy and Space Sciences
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    • v.36 no.3
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    • pp.105-113
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    • 2019
  • Spectroscopic observations of barium star ${\zeta}$ Capricornus (HD204075) obtained at the 8.2 m telescope of the European Southern Observatory, with a spectral resolving power R = 80,000 and signal to noise ratio greater than 300, were used to refine the atmospheric parameters. We found new values for effective temperature ($T_{eff}=5,300{\pm}50K$), surface gravity ($log\;g=1.82{\pm}0.15$), micro-turbulent velocity ($v_{micro}=2.52{\pm}0.10km/s$), and iron abundance ($log\;N(Fe)=7.32{\pm}0.06$). Previously published abundances of chemical elements in the atmosphere of HD204075 were analyzed and no correlations of these abundances with the second ionization potentials of these elements were found. This excludes the possible influence of accretion of hydrogen and helium atoms from the interstellar or circumstellar environment to the atmosphere of this star. The accretion of nuclear processed matter from the evolved binary companion was primary cause of the abundance anomalies. The young age of HD204075 allows an estimation of the time-scale for the creation of the abundance anomalies arising from accretion of interstellar hydrogen and helium as is the case of stars with low magnetic fields; which we estimate should exceed $10^8$ years.

DETERMINATION OF STELLAR SURFACE TEMPERAURE USING ULTRAVIOLET SPECTRA (자외선 스펙트럼을 이용한 별의 표면온도 결정)

  • 강영운;지나현;한미려;최영준;한원용;이우백
    • Journal of Astronomy and Space Sciences
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    • v.15 no.1
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    • pp.91-100
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    • 1998
  • Color indexes and effective temperatures for 25 standard stars have been determined as a pilot project which show a relationship between color index and effective temperature in ultraviolet region. The effective temperature was determined by comparing energy distribution curves derived from the IUE low dispersion spectra with Kurucz atmosphere model. The UV color index was deduced by integrating fluxes in $300{\AA}$ interval of the IUE low disperion spectra. The relation between color index and effective temperature in ultraviolet is similar with that of optical region.

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MAGNETIC FLUX-CURRENT SURFACES OF MAGNETOHYDROSTATIC EQUILIBRIA

  • Choe, G.S.;Jang, Minhwan
    • Journal of The Korean Astronomical Society
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    • v.46 no.6
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    • pp.261-268
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    • 2013
  • Magnetohydrostatic equilibria, in which the Lorentz force, the plasma pressure force and the gravitational force balance out to zero, are widely adopted as the zeroth order states of many astrophysical plasma structures. A magnetic flux-current surface is a surface, in which both magnetic field lines and current lines lie. We for the first time derive the necessary and sufficient condition for existence of magnetic flux-current surfaces in magnetohydrostatic equilibria. It is also shown that the existence of flux-current surfaces is a necessary (but not sufficient) condition for the ratio of gravity-aligned components of current density and magnetic field to be constant along each field line. However, its necessary and sufficient condition is found to be very restrictive. This finding gives a significant constraint in modeling solar coronal magnetic fields as force-free fields using photospheric magnetic field observations.

Exoplanet Science Cases with Small Telescope Network

  • Kang, Wonseok;Kim, Taewoo
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.60.2-60.2
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    • 2019
  • Based on our experience on exoplanet transit observation, we propose the exoplanet science cases with Small Telescope Network. One is the follow-up observation for validation of exoplanet candidates. TESS(Transiting Exoplanet Survey Satellite) is pouring out exoplanet candidates in bright stars(V<15) on all the sky. Since Small Telescope Network will consist of 0.5-1m telescopes, we will expect to produce promising outcomes from the follow-up observation of bright candidates. Next is the transit time observation. By spectroscopy of space and large telescopes during transit event, it can be possible to find the bio signatures in exoplanet atmosphere. So, in terms of cost, it is critical to determine the exact time of transit event. In addition, detecting the variation of transit time can reveal another exoplanet and exomoon in the system. In order to determine the transit time and its variation, the accumulation of transit event data is more important than the quality of photometric data. We expect that it can be a challenging project of Small Telescope Network.

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