KMS of Xinjiang Astronomical Observatory, CAS
| 疏散星团NGC 1912及其附近天区变星搜寻及研究 | |
| Alternative Title | Investigating and Research of Variable Stars in the Open Cluster NGC 1912 and Its Surrounding Field |
李春燕
| |
| Subtype | 硕士 |
| Thesis Advisor | 艾力·伊沙木丁 |
| 2020 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Name | 理学硕士 |
| Degree Discipline | 天体物理 |
| Keyword | 疏散星团,NGC 1912,测光观测,变星 |
| Abstract | 恒星是宇宙的基本组成部分，研究变星能得到恒星内部结构和运动学方面的信息，而疏散星团是研究恒星的理想实验室。同一疏散星团的变星诞生于同一分子云，因此它们可以被认为具有相同的年龄、距离、和化学组成。研究疏散星团中的变星不仅有利于验证恒星演化理论还有利于进一步理解银河系的结构和演化过程。疏散星团NGC 1912作为银河系中疏散星团的一个样本，使用新疆天文台南山1米宽视场望远镜对其进行了9夜的BVR 三色时序观测，共获得3675帧CCD图像，为发现和研究NGC 1912及附近天区的时变天体获取了有效的数据。 本文介绍了观测目标疏散星团NGC 1912的基本特征、观测设备的基本参数和观测设置、测光观测数据的处理过程，同时介绍了所使用的大视场时变天体的搜寻方法。通过XAO时域巡天数据处理系统所得到的测光数据，在疏散星团NGC 1912及其附近天区探测到24颗变星，包括13颗已知变星和11颗本工作新发现的变星。参考 Cantat-Gaudin et al. (2018) 给出的星团成员星，分析了探测到的变星的成员星性质。使用 Gaia DR2 提供的数据，画出了疏散星团的颜色星等图，以及成员星和变星的空间分布、运动学特征图。通过对变星类型的分类和 成员星性质的分析，得到以下结论： 1. 根据变星的光变曲线形状、主周期值，证认了2颗? Dor变星，7颗? Sct变星，3颗EW型变星和1颗未知类型的变星。新发现的11颗变星里包括6颗? Dor变星, 1颗? Sct变星, 1颗 EW 型变星，和3颗E 型变星。 2. 这24颗变星里有6颗变星已经被证认为星团成员星，包括 5 颗? Dor变星和1颗? Sct变星。有一颗已知的? Dor变星具有 LAMOST 的光谱数据，恒星参数为有效温度???? =7193.68±115.75K，表面重力???(?)=4.199±0.19，化学丰度 [? ?/? ] = −0.278 ± 0.112和视向速度 ?? = −5.25 ± 10.08。6颗成员星变星中有3颗是本工作新探测到的，占目前所知成员星变星总数的 50%；它们都是? Dor变星，成员星概率大于 0.5。 3. 通过等年龄线对星团的颜色星等图的拟合结果，得到了成员星变星可能的物理参数:???(???/??) = 8.75, [??/?] = −0.1，? − ? = 10.03 mag，?(B−V) = 0.307。这与 Monteiro 和 Dias (2019) 提供的星团参数基本一致。 |
| Other Abstract | Stars are the cornerstone of modern astrophysics. Variable stars can provide important physical information for stellar structure and stellar motion. Open clusters are ideal laboratories for studying the property of stars. Variable Stars in one open cluster originated in the same interstellar cloud, so they can be assumed to have similar heliocentric distance, age, and chemical composition. Searching for variable stars in the open cluster can not only verify the stellar evolution theory but also offer important clues for further understanding of the structure and the evolution of the Milky Way. The open star cluster NGC 1912 is an open star cluster in the Milky Way. Using the Nanshan 1-m telescope of Xinjiang Observatory, we performed time-series observations for 9 nights. A total of 3675 CCD images were obtained from the 9 nights photometric observations. It provides many sufficient data to research the variable stars in the open cluster NGC 1912 and its surrounding field. We introduced the basic characteristics of the cluster NGC 1912, the observing instruments, and the method of data reduction. At the same time, we introduced the method we used to investigate variable stars in a large field of view. We detected 24 variable stars in the open star cluster NGC 1912 and its surrounding field, including 13 known variable stars and 11 newly detected variable stars. Based on cluster members identified by Cantat-Gaudin et al. (2018), we inferred cluster memberships for these detected variable stars. Using ???? DR2 data, we plotted a new color-magnitude diagram for NGC 1912 and showed the nature of variable cluster members in the heliocentric distance and kinematical properties. The conclusions are as follows: 1. According to the light curve shapes and main period values of the variable stars, we confirmed 2 ? Dor variable stars, 7 ? Sct variable stars, 3 EW-type variable stars, and 1 unknown variable star. And we newly detected 11 variable stars, including 6 ? Dor stars, 1 ? Sct star, 1 EW type binaries, and 3 EA type binaries. 2. Among the 24 variable stars we detected, 6 variable stars were identified as cluster members by Cantat-Gaudin et al. (2018), including 5 ? Dor stars and 1 ? Sct star. There is one known ? Dor star with LAMOST spectral data, and the stellar parameters are ???? = 7193.68±115.75K, ???(?) = 4.199±0.19, [??/?] = −0.278±0.112 and ?? = −5.25 ± 10.08. Three of the 6 variable members, which are all ? Dor stars, are firstly detected in this work, accounting for 50% of the total number of currently known member variable stars. Their member probabilities are larger than 0.5. 3. The main physical parameters of these variable cluster members estimated from thecolor-magnitudediagramtobe???(???/??) = 8.75, [??/?] = −0.1, ?−? = 10.03mag, and E (?-? ) = 0.307. |
| Pages | 48 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xao.ac.cn/handle/45760611-7/4140 |
| Collection | 研究生学位论文 |
| Affiliation | 中国科学院新疆天文台 |
| First Author Affilication | Xinjiang Astronomical Observatory, Chinese Academy of Sciences |
| Recommended Citation GB/T 7714 | 李春燕. 疏散星团NGC 1912及其附近天区变星搜寻及研究[D]. 北京. 中国科学院大学,2020. |
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| 李春燕.pdf（13851KB） | 学位论文 | 暂不开放 | CC BY-NC-SA | Application Full Text | ||
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