• 천문학회보
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• 제34권1호
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• pp.97.2-97.2
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• 2009

• 한국지반공학회논문집
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• 제38권9호
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• pp.19-33
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• 2022

우주 행성 지반 탐사 미션은 1970년대에 활발하게 이루어졌으나 1990~2000년대에는 예산 문제로 쇠퇴기를 맞았다. 그러나 미래에 지구 자원 고갈에 대비하고 헬륨-3 및 희토류와 같이 우주에는 풍부하지만 지구에는 부족한 자원을 탐사하기 위해서는 우주 자원 탐사는 필수적이다. 또한, 우주 기술 발전은 미래 산업 발전의 원동력이 된다. 따라서 우주 자원 탐사 및 활용을 위해 최근 10년 동안 우주 행성 탐사를 위한 선진국 간의 기술 경쟁이 다시 가속화되고 있다. 이 우주 행성 자원 탐사/채굴 및 기지 건설 미션을 위해서는 지반 탐사가 필요하며 현재까지 달에 대한 탐사 미션으로는 Apollo 미션과 LUNA 미션, Chang'E 미션 등이 있고 해당 미션에서 유인 및 로버를 활용한 무인 시추 미션을 수행하였다. 화성 미션으로는 Viking, Spirit/Opportunity, Phoenix, Perseverance 미션, 소행성 탐사 미션은 하야 부사(Hyabusa) 미션이 있었다. 본 논문에서는 현재까지 수행된 우주 행성 광물 자원 탐사 기술에 대해 서술하고 향후 우리나라의 기술과제에 대하여 서술하였다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권1호
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• pp.49.4-49.4
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• 2009

• 천문학회보
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• 제42권2호
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• pp.70.2-70.2
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• 2017

Transit event of exoplanet is a good example of observational studies with youth, because the event is geometrically simple and its analysis is essential to astronomical observation. Therefore, we developed the package of data reduction and aperture photometry in Python for educational purpose. In 27 July, we observed the transit event of TrES-3b with the students of "NYSC Space Science Club" program, and presented the Python package, PyPhotW for data reduction and aperture photometry. PyPhotW consists of simple functions for youth to understand the processes easier. Nonetheless, the photometric results of PyPhotW show a good agreement with those of Source Extractor, ${\Delta}m{\sim}-0.01{\pm}0.03$ and $-0.04{\pm}0.08$ for TrES-3b and TrES-5b time-series observations in 27 - 28 July.

• 천문학회보
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• 제36권1호
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• pp.28.1-28.1
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• 2011

We observed the transiting exoplanet, TrES-2b, with 1.5m telescope at Maidanak Observatory in Uzbekistan. We observed TrES-2 system for six nights, which contained two orbital periods of the planet. Therefore, we obtained the entire light curve of TrES-2b, which covered not only the whole primary transit containing both ingress and egress part, but also non-transit region. We used both R and Y band filters. Especially, Y filter is used first for transit observation and covers relatively longer wavelength ($1.02{\mu}m$ of center wavelength), to provide the light curve less affected by limb darkening. By fitting best model light curve for the obtained one, we determined these observables, transit depth, transit length, and planet's orbital period, which led to the determination of five physical parameters, stellar radius R*, stellar mass M*, inclination i, semi-major axis a, and planetary radius Rp. We will discuss of these results.

• 천문학회지
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• 제56권1호
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• pp.35-40
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• 2023

We have been conducting a exoplanet search survey using Bohyunsan Observatory Echelle Spectrograph (BOES) for the last 18 years. We present the detection of exoplanet candidate in orbit around HD 18438 from high-precision radial velocity (RV) mesurements. The target was already reported in 2018 (Bang et al. 2018). They conclude that the RV variations with a period of 719 days are likely to be caused by the pulsations because the Lomb-Scargle periodogram of HIPPARCOS photometric and H_α EW variations for HD 18438 show peaks with periods close to that of RV variations and there were no correlations between bisectors and RV measurements. However, the data were not sufficient to reach a firm conclusion. We obtained more RV data for four years. The longer time baseline yields a more accurate determination with a revised period of 803 ± 5 days and the planetary origin of RV variations with a minimum planetary companion mass of 21 ± 1 M_Jup. Our current estimate of the stellar parameters for HD 18438 makes it currently the largest star with a planetary companion.

• 대한지구과학교육학회지
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• 제13권3호
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• pp.305-316
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• 2020

이 연구에서는 대학생들이 인식하고 있는 외계행성에 대한 개념을 빅데이터 분석을 하기 위해 외계행성 교육 프로그램과 교육을 받기 전, 후의 개념 변화를 알아보기 위한 질문지를 개발하여 적용하였다. 이를 통한 연구 결과는 다음과 같다. 첫째, 교육을 받기 전에는 외계행성을 단순히 '태양계 바깥(외계)의 행성' 정도의 맥락으로만 이해하고 있었으나, 교육을 받은 후에 중요 키워드 중심으로 '태양계 바깥 항성 주위를 공전하는 행성' 개념으로 확장되었다. 둘째, 대학생들은 매스컴에서 접했던 간접 경험을 토대로 도플러효과, 식현상, 중력렌즈를 활용한 관측한다는 정도의 간단한 답변을 하여 관측 방법에 대한 개념이 매우 부족하였다. 그러나 학생들은 외계행성 탐사와 관련된 내용을 교육 받으면서 외계행성 탐사에 대한 인식이 구체화되었다. 셋째, 대학생들은 외계행성 탐사의 중요성을 단순히 외계생명체의 발견을 넘어서서 태양계를 비롯한 행성의 생성과정과 연구 방법, 인류의 발전으로 확장시키고 있었다. 넷째, 대학생들은 외계행성과 관련된 내용을 지구과학 교육과정에서 소개한다면 과학지식 뿐만 아니라 흥미와 호기심을 일으킬 수 있으므로, 교육과정에서 외계행성에 대한 교육이 필요하다고 인식하였다.

• Journal of Astronomy and Space Sciences
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• 제29권1호
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• pp.41-45
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• 2012

This paper reports the progress of a search for exoplanets with S-type orbits in short-period binary star systems. The selected targets have stellar orbital periods of just a few days. These systems are eclipsing binaries so that exoplanet transits, if planets exist, will be highly likely. We report the results for seven binary star systems.

• 천문학회보
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• 제36권1호
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• pp.27.2-27.2
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• 2011

The Kepler(NASA) and CoRoT(ESA) space telescopes are surveying thousands of exoplanet for finding Earth-like exoplanets with similar environments of the Earth. Then the TPF(NASA), DARWIN(ESA) and many large-aperture ground telescopes have plan for spectroscopic observations of these earth-like exoplanets in next decades. Now, it has been started to simulate the disk averaged spectra of the earthlike exoplanets for comparing the observed spectra and suggesting solutions of environment of these planets. Previous research, the simulations are based on radiative transfer method, but these are limited by optical models of Earth system and instruments. We introduce a new simulation method, IRT(Integrated Ray Tracing) to overcome limitations of previous method. The 3 components are defined in IRT; 1)Sun model, 2)Earth system model (Atmosphere, Land and Ocean), 3)Instrument model. The ray tracing in IRT is simulated in composed 3D real scale space from inside the sun model to the detector of instrument. The Sun model has hemisphere structure with Lambertian scattering optical model. Atmosphere is composed of 16 distributed structures and each optical model includes BSDF with using 6SV radiative transfer code. Coastline and 5 kinds of vegetation distribution data are used to land model structure, and its non-Lambertian scattering optical model is defined with the semi-empirical "parametric kernel method" used for MODIS(NASA) and POLDER(CNES) missions. The ocean model includes sea ice cap structure with the monthly sea ice area variation, and sea water optical model which is considering non-lambertian sun-glint scattering. Computation of spectral imaging and radiative transfer performance of Earth system model is tested with hypothetical space instrument in IRT model. Then we calculated the disk averaged spectra of the Earth system model in IRT computation model for 8 cases; 4 viewing orientation cases with full illuminated phase, and 4 illuminated phase cases in a viewing orientation. Finally the DAS results are compared with previous researching results of radiative transfer method.

• 천문학회지
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• 제55권4호
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• pp.111-121
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• 2022

Based on the light an exoplanet blocks from its host star as it passes in front of it during a transit, the mid-transit time can be determined. Periodic variations in mid-transit times can indicate another planet's gravitational influence. We investigate 83 transits of TrES-1 b as observed from 6-inch telescopes in the MicroObservatory robotic telescope network. The EXOTIC data reduction pipeline is used to process these transits, fit transit models to light curves, and calculate transit midpoints. This paper details the methodology for analyzing transit timing variations (TTVs) and using transit measurements to maintain ephemerides. The application of Lomb-Scargle period analysis for studying the plausibility of TTVs is explained. The analysis of the resultant TTVs from 46 transits from MicroObservatory and 47 transits from archival data in the Exoplanet Transit Database indicated the possible existence of other planets affecting the orbit of TrES-1 and improved the precision of the ephemeris by one order of magnitude. We now estimate the ephemeris to be (2 455 489.66026 BJD_TDB ± 0.00044 d) + (3.0300689 ± 0.0000007) d × epoch. This analysis also demonstrates the role of small telescopes in making precise midtransit time measurements, which can be used to help maintain ephemerides and perform TTV analysis. The maintenance of ephemerides allows for an increased ability to optimize telescope time on large ground-based telescopes and space telescope missions.