Search Publications
DBSCAN Clustering Algorithm for Detection of Nearby Open Clusters Based on Gaia-DR2
Wang, C.; Xu, S. K.; Zhuang, L. H. +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 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 dimensi…
Exoplanet Detection by Astrometric Method
Xu, W. W.; Liao, X. H.; Zhou, Y. H. +1 more
As we known, the exoplanets are mostly detected by the methods of radial velocity and transit, only one is found by the astrometric method. As the data of the gaia to be released, astrometry will become one of the most important method for detecting exoplanets gradually. Based on the position sequence of stars, this paper discusses the calculation…
Analogue Simulation and Orbital Solving Algorithm of Astrometric Exoplanet Detection
Ji, J. H.; Huang, P. H.
Astrometry is an effective method to detect exoplanets. It has many advantages that other detection methods do not bear, such as providing three dimensional planetary orbit and determining the planetary mass. Astrometry will enrich the sample of exoplanets. As the high-precision astrometric satellite Gaia (Global Astrometry interferometer for Astr…
Identifying and Tracking Solar Photospheric Bright Points Based on Three-dimensional Segmentation Technology
Feng, S.; Ji, K. F.; Xiong, J. P. +3 more
Photospheric bright points (PBPs) are tiny and short-lived phenomena which can be seen within dark inter-granular lanes. In this paper, we develop a new method to identify and track the PBPs in the three-dimensional data cube. Different from the previous way such as Detection-Before-Tracking, this method is based on the Tracking-While-Detection. U…
Morphological Classification of High-redshift Massive Galaxies in the COSMOS/UltraVISTA Field
Kong, X.; Fang, G. W.; Ma, Z. Y.
Utilizing the multi-band photometry catalog of the COSMOS (Cosmic Evolution Survey)/UltraVISTA (Ultra-deep Visible and Infrared Survey Telescope for Astronomy) field and the high-resolution HST WFC3 (Hubble Space Telescope Wide Field Camera 3) near-infrared imaging from the CANDELS (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) f…
Hunting for Long-lived Protoplanetary Disks Observed with AKARI/FIS
Liu, Y.; Liu, Q.
Twenty-one YSOs (Young Stellar Objects) in the solar neighbor have been identified through cross-correlating Hipparcos catalog with AKARI/FIS YSO catalog. The reliability of the match is over 90%. The central objects cover spectral types from B to M. The Hipparcos parallaxes enable us to place the objects in the H-R diagram, which can be used to d…
Morphology and Structure of Ultraluminous Infrared Galaxies at z ≈ 2 in the EGS Field
Chen, Y.; Kong, X.; Fang, G. W. +1 more
Using high-resolution HST WFC3 (Hubble Space Telescope Wide Field Camera 3) F160W imaging from the CANDELS-EGS (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey-Extended Groth Strip) field, we present the morphology analysis of 9 ultraluminous infrared galaxies (ULIRGs) at z≈2. We find a wide range of morphological diversities for th…
Determination of Reference Catalogs for Meridian Observations Using Statistical Method
Li, Z. Y.
The meridian observational data are useful for developing high-precision planetary ephemerides of the solar system. These historical data are provided by the jet propulsion laboratory (JPL) or the Institut De Mecanique Celeste Et De Calcul Des Ephemerides (IMCCE). However, we find that the reference systems (realized by the fundamental catalogs FK…
A Research on the New Astronomical Reference Systems
Liu, J. C.
The research of astrometry encompasses all that is necessary to provide the positions and motions of celestial bodies, including observational techniques, instrumentations, processing and analysis of the observational data, reference systems and so on. In the latest decades, great progress has been made in astrometry, including the new theoretical…
Statistical Studies on Geomagnetically Induced Current Events Driven by Earth-directed Full Halo Coronal Mass Ejections
Lin, J.; Liu, C. M.; Wang, K. R. +1 more
Solar activities and eruptions can cause the power transmission system to be an abnormal condition,especially for an extra-long distance electric power transmission system.We analyzed the coronal mass ejection (CME) data from SOHO/LASCO (Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph),and the geomagnetically induced c…