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Water Ice Sublimation Distribution on the Surface of Short Period Comet
Liu, Can; Zhao, Yu-Hui; Ji, Jiang-Hui
Comets are the primitive planetesimals left in the solar system. Studying the evolution of comet nucleus is of great significance for understanding the formation and evolution history of other celestial bodies in the solar system. Under the action of solar radiation, the volatile components of comets sublimate and drive the dust movement, resultin…
Multi-star System Observations Based on the Direct-imaging Method
Zhao, Gang; Chen, Yi-li; Zhu, Yong-tian +1 more
The direct-imaging exploration can obtain comprehensive physical information of exoplanets, which is a key technology to search for extraterrestrial life in the future. In this paper, based on our recent high-contrast imaging data of ground-based telescope, the newly discovered multi-star candidates are presented. In the early stage, combined with…
Using Observations of Solar Vector Magnetic Field from Dual View Points to Remove the 180∘ Ambiguity
Liu, Rui; Zhou, Ru-yun; Wang, Yu-ming +3 more
With Solar Orbiter (SO) being put into successful operational observation, solar magnetic observation has entered the era of remote sensing from dual view points. In this paper, we carried out a simulation of correcting the 180∘ ambiguity of transverse magnetic field with magnetograms from dual view points using an analytical formula as…
A Revisit to the Optical Starlight Polarization Catalogue by Heiles: Distance Update
Meng, Mei-niang; Sun, Xiao-hui
Starlight polarization serves one of the powerful tools to study magnetic fields in the Galactic interstellar medium. Heiles catalogue contains polarization information for 9286 stars, and is by far the biggest. This catalogue has been extensively used to study the magnetic fields. However, the distance parameters of the stars in this catalogue ar…
Two Quasi-periodic Oscillations in ESO 113-G010
Zhang, Peng; Yan, Jing-Zhi; Liu, Qing-Zhong
In the narrow-line Seyfert galaxy (NLS1) ESO 113-G010, two quasi-periodic oscillation (QPO) signals are detected in the XMM-Newton data collected in 2005 November. The XMM-Newton telescope has an exposure longer than 100 ks in the energy range of 0.3-10 keV. The data are analyzed using the Lomb-Scargle periodogram (LSP) and the weighted wavelet Z-…
Automatic Coronagraph Image Classification with Machine Learning Methods
Zhang, Yan; Feng, Li; Li, Hui +5 more
The detection of Coronal Mass Ejections (CMEs) is an important prerequisite for establishing a CME event database and realizing the prediction of CME interplanetary propagation. The Lyman-alpha Solar Telescope (LST) aboard the ASO-S (Advanced Space-based Solar Observatory) satellite will be equipped with a white-light coronagraph. The images with …
Study of the Streamer Current Sheet with White-Light and UV Observations
Feng, Li; Li, Hui; Shi, Guang-lu +2 more
Current sheets (CSs) are the main region where magnetic reconnections can convert magnetic energy into plasma thermal and kinetic energies. We have studied a CS in the streamer occurred on 3 January 2003 by combining the White-Light (WL) images observed by the Large Angle and Spectrometric Coronagraph (LASCO) and the EUV spectra detected by the Ul…
The Galactic Aberration and Its Impact on Astronomical Reference Frames
Liu, Jia-cheng; Liu, Niu
The Galactic aberration effect, also known as the secular aberration drift, is a consequence of the centripetal acceleration of the Solar System Barycenter in the circular orbit around the Galactic center. It causes distance-independent apparent proper motions (the amplitude is about 5 µas · yr - 1) for extragalactic sources which…
DBSCAN Clustering Algorithm for the Detection of Nearby Open Clusters Based on Gaia-DR2two
Gao, Xin-hua; Wang, Chao; Xu, Shou-kun +1 more
In this paper, we attempt to use the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) clustering algorithm to detect nearby open clusters based on the Gaia Data Release 2 (Gaia-DR2). We select 594284 stars (within a distance of 100 pc to the Sun) from the Gaia-DR2 catalog, and construct a five-dimensional phase space (three-dim…
Research Progresses of Halo Streams in the Solar Neighborhood
Zhao, Gang; Liang, Xi-long; Zhao, Jing-kun +1 more
The stellar streams originated from the Galactic halo may be detected when they pass by the solar neighborhood, and they still keep some information at their birth times. Thus, the investigation of halo streams in the solar neighborhood is very important for understanding the formation and evolution of our Galaxy. In this paper, the researches of …