• Journal of Yeungnam Medical Science
• /
• 제24권2호
• /
• pp.329-332
• /
• 2007

일광망막병증은 드물지만 일반적으로 잘 알려진 황반질환이며 이는 직접적인 태양 관찰로 인해 일어난다. 21세 남자가 단안 망원경을 이용하여 좌안으로 약 30초간 태양을 관찰하고 약 48시간 후 시력저하와 중심암점을 호소하였다. 그로부터 약 8개월 후 중심시력은 1.0에서 0.1로 저하되었고 안저검사에서 황백색의 점상 침착물이 관찰되었고 형광안저 촬영에서 망막색소상피의 결손으로 인한 창문 결손이 좌안 중심와에 나타났다. 시야검사에서는 중심 암점이 관찰되었고 시력저하는 빛에 노출된 후 1년이 지난 후에도 지속되었다.

• 천문학회지
• /
• 제29권2호
• /
• pp.207-215
• /
• 1996

To derive coronal temperature, electron density and nonthermal velocity, we have analyzed high resolution spectra (e.g., Fe XII 338.3, Fe XII 352.1, Fe XIV 334.2, Fe XIV 353.8, Fe XV 284.2, Fe XV 321.8, Fe XV 327.0, Fe XVI 335.4, and Fe XVI 360.8) taken from AR 6615 by SERTS (Solar Extreme Ultraviolet Rocket Telescope and Spectrograph). Important findings emerging from the present study are as follows: (1) Temperature estimated from Fe XVI 335.4 and Fe XIV, 334.2 is $\~2.4\times10^6 K$ and no systematic difference in temperature is found between the active region and its adjacent quiet region; (2) Mean electron density estimated from Fe XV is $\~3\times10^9 cm^{-3}\;and\;\~10^{10} cm^{-3}$ from Fe XII and Fe XIV; (3) Mean density of the active region is found to be higher than that of the quiet region by a factor of 2; (4) Nonthermal velocity estimated from Fe XV and Fe XVI is $20\times25 km\;s^{-l}$ which decreases with increasing ionization temperatures. This supports the notion that the nonthermal velocity declines outwards above the transition region.

• 천문학회보
• /
• 제44권2호
• /
• pp.60.4-60.4
• /
• 2019

Small bodies in the solar system are pristine leftovers of planetesimals since the formation epoch (~4.6 Gyr ago). After the formation, icy planetesimals have been preserved in the distant cold place beyond 30 au (i.e., Trans-Neptunian region) until recently without any catastrophic processes but have just been injected into inner region (<~5 au from the Sun) to be observed as comets. On the contrary, asteroids are rocky primitive objects (although some of them contains icy volatiles) distributing in the mainbelt between Mars and Jupiter orbits. Because of frequent encounters in the mainbelt, asteroids have experienced a number of repeated impacts until the present day. Namely, it is important to investigate thermal alternation process of cometary volatiles and refractories in the solar radiation field, whereas collisional and subsequence phenomena of asteroidal bodies. Although recent spacecraft observations revealed the physical natures on the surfaces of comets and asteroids, their interiors still remain largely unexplored. It is likely that a sudden brightening of a comet is associated with rapid sublimation of internal CO and CO2 or phase transition of amorphous H2O. An episodic dust ejection from an asteroid is causally related to an impact among asteroids, sudden sublimation of remaining subsurficial volatiles, etc. Because these transient phenomena provide rare opportunities to investigate their interiors, immediate observations using any optical instruments are particular important. In my presentation, I will review some examples of such transient phenomena in the solar system and propose possible collaborative research using the Korean Small Telescope Network.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 2004년도 한국우주과학회보 제13권1호
• /
• pp.96-96
• /
• 2004

LIST(Lyman-$\alpha$ Imaging Solar Telescope)는 과학 기술 위성 2호의 주 탑재체로써 우리 나라 순수기술로 제작될 KSLV-1에 의해 2005년 12월에 전남 고흥 우주센터에서 발사될 예정이다. LIST는 태양 전체 원반의 진공자외선 영역의 이미지를 지상으로 보내주게 된다. 현재 SPARC에서는 설계 및 제작단계에 들어서고 있으며 따라서 설계를 검증하고 최적화함으로써 LIST가 보내주게 될 데이터의 과학적 활용을 극대화하고자 하였다. (중략)

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 2003년도 한국우주과학회보 제12권2호
• /
• pp.45-45
• /
• 2003

경희대학교 우주탑재체 연구센터에서 개발중인 과학기술위성 2호(STSAT-2) 주탑재체인 Lyman-alpha Imaging Solar Telescope(LIST)의 개발 현황에 대해 논의한다. LIST는 2002년 10월에 개발에 착수한 후 상위수준의 시스템 디자인을 확정하는 System Design Review(SDR)에 이어, 현재 기초 기기 디자인을 수행하는 Preliminary Design Review(PDR) 단계에 와 있다. 본 연구에서는 LIST의 각 부분별 상세 디자인과 시스템 엔지니어링에 대해 논의한다.

• 천문학논총
• /
• 제11권1호
• /
• pp.243-250
• /
• 1996

Data acquisition system mounted on the Solar Flare Telescope at Bohyunsan Optical Astronomy Observatory is briefly described. The system is made up with CCD cameras, an image processor, a PCI-type PC and a SUN workstation. The image processor, MVC 150/40 comprises a variable scan acquisition module, an image manager and a binary correlator computational module. A typical polarization image of a sunspot is presented to demonstrate performance of the system.

• 천문학회보
• /
• 제37권2호
• /
• pp.131.1-131.1
• /
• 2012

We use three-dimensional magnetohydrodynamic (MHD) simulations of flux emergence from solar subsurface to corona. In our previous work, we reported the relation between magnetic-field configuration and the flux expansion factor. Following these results, we investigate where an upflow is generated in an active region and how its location is related to the flux expansion factor. We also derive physical quantities of a real active region from observation data provided by Nobeyama Radioheliograph (NoRH), X-Ray Telescope (XRT), and Extreme Ultraviolet Imaging Spectrometer (EIS) onboard Hinode. These physical quantities are plasma density, temperature and flow. By comparing the simulation result and observational one, we will discuss the properties of the location producing a solar wind.

• 천문학회보
• /
• 제46권2호
• /
• pp.79.1-79.1
• /
• 2021

NxST는 현재 천문연에서 개발중인 30cm 구경의 태양 망원경으로 태양 채층의 모습을 약 1각초의 적정한 영상 해상도로 고분광분해능의 채층선 스펙트럼 자료를 고속으로 얻어낼 수 있다. NxST는 미국과 유럽, 그리고 국내 1대를 건설하여 전지구적으로 연속적인 데이터를 획득할 수 있다. NxST의 관측자료는 1) 우주환경예보의 최초이며 유일인자인 태양을 실시간으로 감시할 수 있고 2) 태양 채층의 파동과 관련된 연구를 수행하는데 활용될 수 있다. 본 발표에서는 NxST의 연구주제들을 살펴보고 이로부터 도출된 시스템의 개념 설계를 제시한다.

• 천문학회보
• /
• 제37권1호
• /
• pp.89.1-89.1
• /
• 2012

We have investigated a coronal jet observed near the limb on 2010 June 27 by the Hinode/X-Ray Telescope (XRT), EUV Imaging Spectrograph (EIS), and Solar Optical Telescope (SOT), and the SDO/Atmospheric Imaging Assembly (AIA), Helioseismic and Magnetic Imager (HMI), and on the disk by STEREO-A/EUVI. From EUV (AIA and EIS) and soft X-ray (XRT) images we have identified both cool and hot jets. There was a small loop eruption in Ca II images of the SOT before the jet eruption. Using high temporal and multi wavelength AIA images, we found that the hot jet preceded its associated cool jet by about 2 minutes. The cool jet showed helical-like structures during the rising period. According to the spectroscopic analysis, the jet's emission changed from blue to red shift with time, implying helical motions in the jet. The STEREO observation, which enabled us to observe the jet projected against the disk, showed that there was a dim loop associated with the jet. We have measured a propagation speed of ~800 km/s for the dimming front. This is comparable to the Alfven speed in the loop computed from a magnetic field extrapolation of the HMI photospheric field measured 5 days earlier and the loop densities obtained from EIS Fe XIV line ratios. We interpret the dimming as indicating the presence of Alfvenic waves initiated by reconnection in the upper chromosphere.

• 천문학회보
• /
• 제36권2호
• /
• pp.89.1-89.1
• /
• 2011

We have investigated a coronal jet near the limb on 2010 June 27 by Hinode/X-Ray Telescope (XRT), EUV Imaging Spectrograph (EIS), Solar Optical Telescope (SOT), SDO/Atmospheric Imaging Assembly (AIA), and STEREO. From EUV (AIA and EIS) and soft X-ray (XRT) images we identify the erupting jet feature in cool and hot temperatures. It is noted that there was a small loop eruption in Ca II images of the SOT before the jet eruption. Using high temporal and multi wavelength AIA images, we found that the hot jet preceded its associated cool jet. The jet also shows helical-like structures during the rising period. According to the spectroscopic analysis, the jet structure changes from blue shift to red one with time, implying the helical structure of the jet. The STEREO observation, which enables us to observe this jet on the disk, shows that there was a dim loop associated with the jet. Comparing the observations from the AIA and STEREO, the dim loop corresponds to the jet structure which implies the heated loop. Considering that the structure of its associated active region seen in STEREO is similar to that in AIA observed 5 days before, we compared the jet morphology on the limb with the magnetic fields extrapolated from a HMI vector magnetogram observed on the disk. Interestingly, the comparison shows that the open field corresponds to the jet which is seen as the dim loop in STEREO. Our observations (XRT, SDO, SOT, and STEREO) are well consistent with the numerical simulation of the emerging flux reconnection model.