• 제목/요약/키워드: Near Space

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국내 천문대 상공의 수증기량 조건과 적외선 관측 (PRECIPITABLE WATER VAPOR CONDITIONS FOR INFRARED OBSERVATIONS AT KOREAN ASTRONOMICAL OBSERVATORIES)

  • 이성호;백정호;문봉곤;진호;조정호;차상목;조승현;박영식;육인수;남욱원;박수종
    • Journal of Astronomy and Space Sciences
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    • 제24권4호
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    • pp.339-348
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    • 2007
  • 한국천문연구원은 $1\;-\;5{\mu}m$ 파장영역에서 관측 가능한 근적외선 카메라 KASINICS(Korea Astronomy and Space science Institute Near Infrared Camera System)를 개발하였다. 열적외선이 강해지는 $3{\mu}m$ 이상의 파장영역에서는 대기 중의 수증기에 의한 대기투과도가 중요해진다. 이 논문에서는 국내 천문대의 적외선 관측 조건을 알아보기 위해 한국천문연구원의 GPS 신호를 이용한 PWV(Precipitable Water Vapor) 측정 시스템을 사용하여 2006년 7월부터 2007년 8월까지의 보현산 및 소백산 상공의 월별 PWV 분포를 조사하였다. 그 결과, 국내 대기 수증기량 조건은 지표면의 이슬점온도를 이용해서 추정한 예상보다 좋았으며, 특히 가을철 및 겨울철에는 미국 Kitt Peak 천문대 상공의 조건과 비교하여 크게 다르지 않음을 확인하였다.

High Resolution Near Infrared Spectrum of NGC 7023

  • Le, Huynh Anh N.;Pak, Soojong;Lee, Hye-In;Lee, Jae-Joon;Nguyen-Luong, Quang;Kaplan, Kyle;Jaffe, Daniel T.
    • 천문학회보
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    • 제39권2호
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    • pp.93.1-93.1
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    • 2014
  • The reflection nebula NGC 7023 is a typical example of a photodissociation region (PDR), which consists of high density molecular gas that is exposed to an intense UV radiation field. The source of the UV photons in NGC 7023 is the young pre-main-sequence Be star HD 200755. We present our near-infrared high-resolution (R ~ 40,000) spectrum of NGC 7023, covering a region of $1{\times}15$ arcseconds, observed during the commissioning runs of IGRINS (Immersion GRating near-INfrared Spectrometer). The spectrum shows many strong narrow emission lines that arise from the molecular rovibrational transitions of H2. From the intensity ratios between these H2 lines, we investigate physical conditions within the PDR such as the temperature, density, and pressure. The high spectral resolution of IGRINS allows us to resolve the velocity field of the PDR. In addition, we compare the IGRINS spectrum to Cloudy PDR model.

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근거리 빔 스캐닝 안테나에 관한 연구 (A Study on the Near Field Beam Scanning of the Array Antenna)

  • 송우영
    • 한국정보전자통신기술학회논문지
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    • 제10권3호
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    • pp.220-224
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    • 2017
  • 본 논문은 근거리 빔 스캐닝 배열 안테나의 3차원 초점을 갖도록 급전하는 방법에 대하여 연구하였다. 기존의 배열 안테나 이론은 원거리 측정점에 대한 것이 대부분이다. 기본적 개념은 방사되는 신호의 위상을 원하는 지점에서 동위상이 되도록 급전하는 것이다. 본 연구에서도 이러한 기본적인 원리를 적용하여 배열 안테나 크기에 비해 측정점의 거리가 근거리에 위치한 점에서 최대 수신 전력을 갖도록 위상을 보상해 주는 방법을 제안 하였다. 제안한 방법으로 자유 공간에 11개의 안테나를 3가지 방법으로 배열하여 3차원 공간에서의 방사패턴과 근거리내의 평면에서의 수신 신호의 크기에 계산하여 대한 등고선 그래프를 작성하였다. 그래프를 분석한 결과 배열 안테나의 근거리 영역에서 빔 스캐닝이 가능하다는 것을 확인하였다.

A New Era of Space Shuttle

  • Sun Kyu Kim
    • Journal of Astronomy and Space Sciences
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    • 제2권1호
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    • pp.1-6
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    • 1985
  • The U.S. Space Shuttle represents the beginning of a new era in transportation and is the critical element in the industrialization of the near-Earth-space. Most of its flights are dedicated to reducing costs launching commercial satellites. However, it provides a microgravity environment for processing unique and improved materials which is generating great interest in both civilian and military sectors. The space shuttle is also the necessary step in establishing a permanent space station which could host materials analysis laboratories and commercial processing facilities. This paper reviews the different elements of the space shuttle transportation system, a typical mission scenario, and discusses current activities in materials processing in space.

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The IGRINS Spectra of Late-Type Stars

  • Park, Sunkyung;Lee, Jeong-Eun;Kang, Wonseok;Lee, Sang-Gak;Chun, Moo-Young;Kim, Kang-Min;Yuk, In-Soo;Jeong, Ueejeong;Jaffe, Daniel T.
    • 천문학회보
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    • 제40권2호
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    • pp.58.2-58.2
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    • 2015
  • We present a library of high spectral resolution (R ~ 40,000) and high signal-to-noise ratio (S/N ~ 200) near-infrared spectra of ~50 late-type stars. The spectra of late-type stars were obtained with Immersion GRating INfrared Spectrograph (IGRINS) covering the full H and K band. The stars are mainly from MK standard stars which have well-defined spectral types and luminosity classes and cover wide ranges of effective temperatures and surface gravities. The spectra are corrected for telluric absorption lines and absolutely flux calibrated using the Two Micron All Sky Survey (2MASS) photometry. In this work, we present the preliminary results of spectroscopic diagnostics for stellar physical parameters. Our ultimate goal is to provide a library of near-infrared spectra of standard stars, which covers all spectral types and luminosity classes, with a high spectral resolution and high signal-to-noise ratio.

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Photometry of the long-period eclipsing polar V1309 Ori

  • Kim, Y.;K. Reinsch;Y. B. Jeon
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2003년도 한국우주과학회보 제12권2호
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    • pp.24-24
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    • 2003
  • We present preliminary results about the quasi-simultaneous near-infrared light curves of the long-period eclipsing polar V1309 Ori in the J, H, K', and K bands with almost complete orbital phase coverage using the CFHT-IR camera. The optical light curve in the V and R bands, obtained by 1.8m Telescope at BOAO, will be also presented. The shape and the amplitude of the orbital light curve change significantly from optical to near-infrared wavelengths.

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Magnetospheric and ionospheric responses to the passage of solar wind discontinuity on 24 November 2008

  • Kim, Khan-Hyuk;Park, Jong-Sun;Lee, Dong-Hun;Park, Young-Deuk;Angelopoulos, V.;Nishitani, N.;Hori, T.;Shiokawa, K.;Yumoto, K.;Baishev, D.
    • 천문학회보
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    • 제36권2호
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    • pp.91-91
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    • 2011
  • The passage of the interplanetary discontinuity (i.e., sudden increases in the solar wind speed, density, and IMF strength) was detected by ACE near GSE (x, y, z) ~ (222, -36, 3) Re upstream of Earth around 22:48 UT on November 24, 2008. About 55 min later, this solar wind discontinuity was observed by Geotail near GSE (x, y, z) ~ (23, 18, -7) Re in front of Earth's bow shock. From the propagation time of the solar wind discontinuity between ACE and Geotail, it is expected that the discontinuity front is aligned with the Parker spiral and strikes the postnoon dayside magnetopause first. Using coordinated multi-point measurements (THEMIS and GOES) at or in geosynchronous orbit, we observed a tailward propagating sudden impulse (SI), excited by the interplanetary discontinuity, around 23:50 UT with its front retaining alignment similar to that of solar wind discontinuity. The SI event appears a negative-then-positive variation in the H component at high latitude Chokurdakh (CHD: MLAT ~ 64.7 deg) in the prenoon sector, which is opposite sense of normal SI event. During the positive deflection at CHD, the SuperDARN Hokkaido radar detected the downward motion of the ionosphere, implying westward electric field enhancement, at subauroral latitudes near CHD meridian. In our study we will discuss magnetospheric and ionospheric responses to the passage of the solar wind discontinuity using multi-point observations in space and on the ground.

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