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
제53권 제1호 (2020년 2월) 3건
1.
2020.02
구독 인증기관 무료, 개인회원 유료
The recent study of Chae et al. (2017) found a one-to-one correspondence between plasma blobs out owing along a ray formed after a coronal mass ejection (CME) and small X-ray ares. In the present work, we have examined the spatial con guration and the eruption process of the ares that are associated with the blobs by analyzing EUV images and magnetograms taken by the SDO/AIA and HMI. We found that the main are and the successive small ares took place in a quadrupolar magnetic con guration characterized by predominant magnetic elds of positive polarity, two minor magnetic fragments of negative polarity, and a curved polarity inversion line between them, which suggests that the formation process of the blobs may be similar to that of the parent CME. We also found that the successive ares resulted in a gradual change of the quadrupolar magnetic con guration, and the relevant migration of aring kernels. The three-dimensional geometry and the property of the current sheet, that is often supposed to be embedded in an observed post-CME ray, seem to keep changing because of mutual feedback between the successive ares and the temporal change of the magnetic eld con guration. Our results suggest that the observed post-CME rays may not re ect the characteristics of the current sheet responsible for the impulsive phase of the are.
4,000원
2.
2020.02
구독 인증기관 무료, 개인회원 유료
Andrew Gould, Yoon-Hyun Ryu, Sebastiano Calchi Novati, Weicheng Zang, Michael D. Albrow, Sun-Ju Chung, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, In-Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Charles Beichman, Geoff Bryden, Sean Carey, B. Scott Gaudi, Calen B. Henderson, Wei Zhu, Pascal Fouque, Matthew T. Penny, Andreea Petric, Todd Burdullis, Shude Mao
At q = 1.81 ± 0.20 × 10-5, KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio q of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent "pile-up" at q = 5-10 ×10-5. The event was observed by Spitzer, yielding a microlens-parallax πE measurement. Combined with a measurement of the Einstein radius θE from finite-source effects during the caustic crossings, these measurements imply masses of the host Mhost = 1.14+0.10-0.12 M⊙ and planet Mplanet = 7.59+0.75-0.69 M⊕, system distance DL = 3.38+0.22-0.26 kpc and projected separation a⊥ = 4.27+0.21-0.23 AU. The blended light, which is substantially brighter than the microlensed source, is plausibly due to the lens and could be observed at high resolution immediately.
5,200원
3.
2020.02
구독 인증기관 무료, 개인회원 유료
We report the detection of exoplanet candidates in orbits around HD 60292 and HD 112640 from a radial velocity (RV) survey. The stars exhibit RV variations with periods of 4953 days and 6136 days, respectively. These detections are part of the Search for Exoplanets around Northern Circumpolar Stars (SENS) survey using the ber-fed Bohyunsan Observatory Echelle Spectrograph installed at the 1.8-m telescope of the Bohyunsan Optical Astronomy Observatory in Korea. The aim of the survey is to search for planetary or substellar companions. We argue that the periodic RV variations are not related to surface inhomogeneities; rather, Keplerian motions of planetary companions are the most likely interpretation. Assuming stellar masses of 1:7 0:2M⊙ (HD 60292) and 1:8 0:2M⊙ (HD 112640), we obtain minimum planetary companion masses of 6:5 1:0MJup and 5:0 1:0MJup, and periods of 495:4 3:0 days and 613:2 5:8 days, respectively.
4,000원
