간행물
천문학회지 KCI 등재 SCOPUS Journal of The Korean Astronomical Society
- 발행기관 한국천문학회
- 자료유형 학술지
- 간기 반년간
- ISSN 1225-4614 (Print)2288-890X (Online)
- 수록기간 1968 ~ 2024
- 주제분류 자연과학 > 천문학 자연과학 분류의 다른 간행물
- 십진분류KDC 440DDC 520
권호리스트/논문검색
제55권 제4호 (2022년 8월) 5건
1.
2022.08
구독 인증기관 무료, 개인회원 유료
Polarimetric measurements of the lunar surface from lunar orbit soon will be available via Wide-Field Polarimetric Camera (PolCam) onboard the Korea Pathfinder Lunar Orbiter (KPLO), which is planned to be launched in mid 2022. To provide calibration data for the PolCam, we are conducting speckle polarimetric measurements of the nearside of the Moon from the Earth’s ground. It appears that speckle imaging of the Moon for scientific purposes has not been attempted before, and there is need for a procedure to create a “lucky image” from a number of observed speckle images. As a first step of obtaining calibration data for the PolCam from the ground, we search for the best sharpness measure for lunar surfaces. We then calculate the minimum number of speckle images and the number of images to be shift-and-added for higher resolution (sharpness) and signal-to-noise ratio.
4,200원
2.
2022.08
구독 인증기관 무료, 개인회원 유료
This study presents the characteristics of publications in the Journal of Korean Astronomy Society (JKAS) from 1968 to 2021. JKAS has published 763 research articles over the past 54 years. In addition, 376 proceedings were also published with research articles. There were slight increases and decreases in the number of articles published in JKAS in the 1990s and 2000s, and in 2015 there was the highest recorded number of articles published for a given year. Since then, the number of articles has tended to decrease each year, up to and including the most recent period (2020–2021), which includes the Coronavirus pandemic. However, since theory centered research is primarily conducted without being swayed by society and policies, and that the proportion of authors belonging to educational institutions, such as universities, is high, the future direction of JKAS is encouraging. There are also positive developments including sustained researchers affiliated with international institutions at greater than approximately 23%, as well as improvements in the impact factor. Therefore, it is important to not be deterred by the decreasing trends of the quantitative aspect, but to respond positively by determining a future roadmap.
4,300원
3.
2022.08
구독 인증기관 무료, 개인회원 유료
Paige Yeung, Quinn Perian, Peyton Robertson, Michael Fitzgerald, Martin Fowler, Frank Sienkiewicz, Kal´ee Tock
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 BJDTDB ± 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 groundbased telescopes and space telescope missions.
4,200원
4.
2022.08
구독 인증기관 무료, 개인회원 유료
Sun-Ju Chung, Jennifer C Yee, Andrej Udalski, Andrew Gould, Michael D Albrow, Youn Kil Jung, Kyu-Ha Hwang, Cheongho Han, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W Pogge, Radek Poleski, Przemek Mr´oz, Pawe l Pietrukowicz, Jan Skowron, Micha l K Szyma´nski, Igor Soszy´nski, Szymon Koz lowski, Krzysztof A Rybicki, Patryk Iwanek, Marcin Wrona, Mariusz Gromadzki, Krzysztof Ulaczyk
We present the analysis of a planetary microlensing event OGLE-2019-BLG-0362 with a shortduration anomaly (∼0.4 days) near the peak of the light curve, which is caused by the resonant caustic. The event has a severe degeneracy with Δχ2 = 0.9 between the close and the wide binary lens models both with planet-host mass ratio q ≃ 0.007. We measure the angular Einstein radius but not the microlens parallax, and thus we perform a Bayesian analysis to estimate the physical parameters of the lens. We find that the OGLE-2019-BLG-0362L system is a super-Jovian-mass planet Mp = 3.26+0.83 −0.58 MJ orbiting an M dwarf Mh = 0.42+0.34 −0.23 M⊙ at a distance DL = 5.83+1.04 −1.55 kpc. The projected star-planet separation is a⊥ = 2.18+0.58 −0.72 AU, which indicates that the planet lies beyond the snow line of the host star.
4,000원
5.
2022.08
구독 인증기관 무료, 개인회원 유료
We report the discovery of four quasars with M1450 ≳ −25.0 mag at z ∼ 5 and supermassive black hole mass measurement for one of the quasars. They were selected as promising high-redshift quasar candidates via deep learning and Bayesian information criterion, which are expected to be effective in discriminating quasars from the late-type stars and high-redshift galaxies. The candidates were observed by the Double Spectrograph on the Palomar 200-inch Hale Telescope. They show clear Lyα breaks at about 7000–8000 ˚A, indicating they are quasars at 4.7 < z < 5.6. For HSC J233107-001014, we measure the mass of its supermassive black hole (SMBH) using its Civ λ1549 emission line. The SMBH mass and Eddington ratio of the quasar are found to be ∼108 M⊙ and ∼0.6, respectively. This suggests that this quasar possibly harbors a fast growing SMBH near the Eddington limit despite its faintness (LBol < 1046 erg s−1). Our 100% quasar identification rate supports high efficiency of our deep learning and Bayesian information criterion selection method, which can be applied to future surveys to increase high-redshift quasar sample.
4,000원
