激变变星中的快速光变

文中综述了激变变星中快速光变的研究进展，讨论了闪变，相干振荡和准周期振荡的观测特征和可能的产生机制。     

类新星食变星PG1030+590的光电测光

PG1030+590是最近发现的类新星食变星。我们首先给出该双星系统的高速光电测光结果及U、B、V和R光变曲线。通过利用激变变星的模型对观测结果进行分析,我们求得其物理和几何参数:白矮星子星质量M_1=0.83±0.22M_⊙,晚型星子星质量M_2=0.35±0.06M_⊙,晓型星子星半径R_2=0.37±0.08R_⊙以及轨道倾角i=81°±2°。我们还利用两种不同方法求出围绕白矮星的吸积盘的半径R_d≈0.32R_⊙,并把这个结果与密近双星中吸积盘半径的各理论模型进行了比较。     

激变食变星Ⅲ.AC Cancri

AC Cnc是周期为7~h13~m的类新星食变星。由于AC Cnc是双谱食双星,而且具有较对称的食,所以在对激变食变星的系统研究中,我们选择了该双星来进行观测。本文利用拟合光变曲线的方法对AC Cnc进行了测光解分析、并得到轨道倾角i=74.5°±0.8°,白矮星质量M_1=0.74±0.07M_⊙,晚型星质量M_2=0.97±0.08M_⊙。AC Cnc中吸积盘的径向温度分布可以近似地表示为T(r)∝r~(-0.5),吸积盘边缘温度为7600K。晚型星向白矮星的质量转移率大约为7×10~(-9)M_⊙yr~(-1)。AC Cnc的距离近似地等于500±100pc。     

PG激变星候选天体的光变曲线

我们于1989年用北京天文台兴隆观测站的60/90/180厘米施密特望远镜及Thomson红敏CCD对14个PG候选激变变星进行光度观测.其光变曲线特性表明:PG0027+260,PG0818+513,和PC1030+590为激变食变星,PG1341—079 是一个可能的激变食变星,PG1551+719为SU UM_a型矮新星,此外还有6个天体的光变曲线有激变星特有的闪变特征.因此PG样本中,激变变星的成功率为79％.PG1030+590的轨道周期为3~h279,PG1717+413的闪变变幅在二个月内有明显变化,它与本身的亮度无明显相关,说明闪变变幅的变化可能是亮斑的局部效应.     

短周期激变变星周期分布的新统计

我们对周期小于周期分布空缺段的激变变星，重新进行了周期分布统计，使用了比Ｗａｒｎｅｒ等人更多，更新的资料，统计中发现一个ＡＭＨｅｒ型ＣＶｓ：ＧＲＵＶ１偏离了Ｗａｒｎｅｒ等人的统计结果，我们给出了ＣＶＳ新的周期分布图和相应于此分布的随机概率。虽然结果与Ｗａｒｎｅｒ等人的不同，但周期分布同磁场仍呈现一定的相关性，磁激变变星与非磁激变变星同样显示出成团趋势。     

激变变星中的白矮星

仅在过去的10年中,由于采用了地面和空同时的光谱观测激变变星中正处于吸积过程的白矮星,在激变变星（CV）的研究方面出现了全新的途径。这些光谱探测开拓了恒星包层、角动量团儿CV演化中吸积物理学研究的新前没中。这篇评论包括了激变变星中的白矮星研究的方方面面：（1）表面温度;（2）吸积加热和冷却的不;(3)在高度倾斜的CV中吸收幕帘（盘的上面的大气）的影响和特点;（4）白矮星光球的化学丰度;（6）吸积带;（7）吸积的模拟。     

短周期激变变星周期分布的新统计

我们对周期小于周期分布空缺段的激变变星(CVs),重新进行了周期分布统计,使用了比Warner等人更多、更新的资料.统计中发现一个AM Her型CVs:GRU V1偏离了Warner等人的统计结果.我们给出了CVs 新的周期分布图和相应于此分布的随机概率.虽然结果与Warner等人的不同,但周期分布同磁场仍呈现一定的相关性,磁激变变星(MCVs)与非磁激变变星(NMCVS)同样显示出成团趋势.     

EROS-II Variable Stars: Eclipsing Binaries in the EROS Microlensing Surveys

More than 10 years of microlensing survey observations by the EROS Collaboration have monitored several million stars, amongst them several thousand eclipsing binary stars. In this poster we present some of the difficulties and rewards of the study of this immense database.Based on observations made at ESO by the EROS collaboration     

A New Light Curve Analysis of the Eclipsing Binary SX Aur

Using WOOD 's (1972) model, we have analysed BONDARENKO 's (1974) two-colour photoelectric observations – till now unsolved – of the eclipsing binary SX Aur. Our photometric solutions turn out to be in substantial agreement with those derived by CHAMBLISS and LEUNG (1979); they confirm that SX Aur is a post-mass exchange (case A) semi-detached system.     

基于SVM的食双星光变曲线自动分类算法

提出一种基于机器学习的食双星光变曲线自动分类算法。首先对数据进行预处理,将食双星光变曲线数据归一化,并通过滤波/插值降低噪声;其次使用快速傅里叶变换提取频率信号作为特征向量;最后利用特征向量训练支持向量机获得自动分类模型。使用Python实现算法并抓取CALEB和GCVS数据验证,分析特征向量、支持向量机核函数与惩罚系数对分类正确率的影响,优化后所得分类模型正确率达到92.8%(训练集)和89.0%(测试集),最后使用所得分类模型对第3方数据进行分类,正确率为88.8%,结果证明提出的分类算法的有效性。     

Short Time-Scale Variability in the Light Curve of~TW~Draconis

We have re-analyzed old photometric UBV data obtained by Papoušek et al. at Skalnaté Pleso, Slovakia (1967–1980) and Brno, Czech Republic (1976–1979) observatories and analyzed new own CCD measurements (Brno, 2003–2005). In both set of photometric data the oscillations in the vicinity of the primary minimum were found. The detected periods are compatible with the previously published ones.     

Light Curve Synthesis for the Eclipsing Binary BB Peg

Using Wood's (1972) model we have reanalyzed Cerruti-Sola and Scaltriti's (1980) photoelectric observations of the eclipsing binary BB Peg. Our photometric elements, which turn out to be considerably different from the earlier preliminary results, describe BB Peg as a contact system, in which the component eclipsed at the deeper minimum is smaller than its companion. BB Peg appears to conform to the general properties of the W-type subclass of W UMa systems.     

A Method For Eclipsing Component Identification in Large Photometric Datasets

We describe an automated method for assigning the most likely physical parameters to the components of an eclipsing binary (EB), using only its photometric light curve and combined color. In traditional methods (e.g. WD and EBOP) one attempts to optimize a multi-parameter model over many iterations, so as to minimize the chi-squared value. We suggest an alternative method, where one selects pairs of coeval stars from a set of theoretical stellar models, and compares their simulated light curves and combined colors with the observations. This approach greatly reduces the EB parameter-space over which one needs to search, and allows one to determine the components' masses, radii and absolute magnitudes, without spectroscopic data. We have implemented this method in an automated program using published theoretical isochrones and limb-darkening coefficients. Since it is easy to automate, this method lends itself to systematic analyses of datasets consisting of photometric time series of large numbers of stars, such as those produced by OGLE, MACHO, TrES, HAT, and many others surveys.     

A CCD light curve of PG 0818+513

We made high-speed CCD photometry (time resolution 63 s) of PG 0818+513 on 1989 March 27 and April 2 and obtained two complete light curves. This object is proved to be a cataclysmic eclipsing binary with an orbital period of 0.1559 d.     

Investigation of Times of Minima of Selected Early-Type Eclipsing Binaries

New precise times of minimum light for several early-type eclipsing binaries were obtained at three observatories. The changes of period of the following measured binaries are discussed: V1182 Aql, LY Aur, SZ Cam, FZ CMa, QZ Car, LZ Cen, V606 Cen, AH Cep and TU~Mus.     

Radial Velocity and Light Curve Analysis of the Eclipsing Binary Nn Vir

The eclipsing binary NN Vir is a short period system showing an EW-type light curve. Photometric observations of NN Vir were done by Gomez–Ferrellad and Garcia–Melendo (1997) at Esteve Duran Observatory. The first spectroscopic observations of this system were obtained by Rucinski and Lu (1999). The radial velocity and light curves analysis was made with the latest version of the Wilson program (1998), and the geometric and physical elements of the system are derived. From the simultaneous solutions of the system, we determined the masses and radii of the components: 1.89 M _⊙ and 1.65 R _⊙ for the primary component; 0.93 M _⊙ and 1.23 R _⊙ for the secondary component. We estimated effective temperatures of 7030 K for the primary and 6977 K for the secondary component.