Subjects: Astronomy submitted time 2023-08-02 Cooperative journals: 《天文学报》
Abstract： The orbital eccentricity is one of the key parameters to describe the orbit of celestial bodies, which can provide important clues to reveal their dynamical evolution, and thus help to understand their formation and evolution processes along with the physical mechanisms behind them. The continuous improvement of observational technologies enables us to explore the orbit of celestial bodies beyond the Solar System, i.e., from stellar systems to planetary systems. Focusing on the orbital eccentricity of celestial bodies, this paper reviews the progress in stellar systems (including the main sequence stars, brown dwarfs, and compact stars) and planetary systems (including gas-giants, low-mass exoplanets such as ``super-Earth'' and ``sub-Neptune''), and summarizes several similarities and issues among the investigations of orbital eccentricity under different scales. Finally, based on the ongoing and future astronomical facilities and missions, we discuss the future prospect on eccentricity studies of stellar systems, extrasolar planetary systems and even extrasolar satellite systems.
Subjects: Astronomy submitted time 2023-08-02 Cooperative journals: 《天文学报》
Abstract： The Chinese Survey Space Telescope (CSST) is the first large space optical telescope of China. It will perform scientific observations and yield important scientific results, e.g. multi-color photometry to find and characterize exoplanets. The precision of time-domain photometry affected by various astrophysical and instrument noises is crucial for exoplanet detection and characterization. This paper constructs a time-domain model to simulate the stellar signal and various noises based on the main technical parameters of CSST published so far. The precision of photometry is analyzed by modeling the signal and noises for an example of the gazing mode in the i band. We investigate and discuss the contribution of various noises while doing aperture photometry, especially the jitter noise caused by pointing jitter and pixel response inhomogeneity. The test results also provide the recommended size of aperture photometry. Jitter noise can be suppressed by reducing jitter amplitude and uniforming pixel or by using differential photometry with reference stars. Our simulation results can be applied to the precision prediction of time-domain photometry, the refinement of CSST instrumental specifications, evaluation of exoplanet detection capabilities, and data reduction progress for CSST.
Subjects: Astronomy >> Astrophysical processes submitted time 2019-04-17 Cooperative journals: 《天文研究与技术》
Abstract： 对新疆天文台(XAO)南山一米大视场天文望远镜（NOWT）观测的历史数据，我们进行细致的数据挖掘，发现了百余颗变源。数据处理pipeline为XAO时域巡天数据处理包，该处理包同时考虑了测光系统内部权重和相关性，并结合快速混合算法编写的。除去已知的变源，我们发现了很多新的变源。对新变源证认的过程中，我们将结果与LAMOST、GCVS、VSX、Gaia DR2等星表进行了交叉。在讨论部分，我们对各星表的使用情况给出了说明。对于新源最后发现绝大部分是食双星，少部分是脉动变星，并有一颗表现相对复杂的变源。
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