收集了所有可用的光度和光谱观测结果，并用作对近距离双星IM Mon进行详细分析的基础。该双星的轨道周期被修正为1.19024249（0.00000014）天。通过光变曲线的分析，得到了组成星的Roche等势、（B，V）和H_p波段的分光光度和分光半径，以及质量比q、轨道倾角i和次冷低质量组分的有效温度T_eff。与文献中的接触构型估计相反，IM Mon被分类为分离的二元系统。通过同时求解光速和径向速度曲线，推导出IM Mon的绝对参数：M1，2 =5.50（0.24）M_o和3.32（0.16）M_0，R1，2=3.15（0.04）Ro和2.36（0.03）Ro，Teff 1，2 =17500（350）K和14500（550）K，表明主星和次星的光谱类型分别为B4和B6.5 ZAMS星。高分辨率光谱的模拟显示，组成星的自转速度为V_rot1=147（15）km/s和V_rot2=90（25）km/s。测光距离353（59）pc比依巴谷距离341（85）pc更精确可靠。IM Mon的进化年龄为11.5（1.5）Myr。运动学和动力学分析支持成员的年轻薄盘人口系统IM Mon的Ori OB 1a协会动态。最后，利用IM Mon参数信息，推导了Ori OB 1a亚群的距离、年龄和金属丰度信息。
英文摘要：
All available photometric and spectroscopic observations were collected and used as the basis of a detailed analysis of the close binary IM Mon. The orbital period of the binary was refined to 1.19024249(0.00000014) days. The Roche equipotentials, fractional luminosities (in (B, V) and H_p bands) and fractional radii for the component stars in addition to mass ratio q, inclination i of the orbit and the effective temperature T_eff of the secondary cooler less massive component were obtained by the analysis of light curves. IM Mon is classified to be a detached binary system in contrast to the contact configuration estimations in the literature. The absolute parameters of IM Mon were derived by the simultaneous solutions of light and radial velocity curves as M_1,2=5.50(0.24)M_o and 3.32(0.16)M_o, R1,2=3.15(0.04)R_o and 2.36(0.03)R_o, T_eff1,2=17500(350) K and 14500(550) K implying spectral types of B4 and B6.5 ZAMS stars for the primary and secondary components respectively. The modelling of the high resolution spectrum revealed the rotational velocities of the component stars as V_rot1=147(15) km/s and V_rot2=90(25) km/s. The photometric distance of 353(59) pc was found more precise and reliable than Hipparcos distance of 341(85) pc. An evolutionary age of 11.5(1.5) Myr was obtained for IM Mon. Kinematical and dynamical analysis support the membership of the young thin-disk population system IM Mon to the Ori OB1a association dynamically. Finally, we derived the distance, age and metallicity information of Ori OB1a sub-group using the information of IM Mon parameters.
We present the first evidence for the pulsations of primary components of four eclipsing binary systems. The TESS light curves of the targets are analyzed, the light and the absolute parameters are derived. Fourier analyses are applied to the residual data subtracted from the binary models to reveal the pulsational characteristics of the primaries. The components of the systems are compared to well-known binary systems of the same morphological type. The types of pulsational classes for the primaries are also discussed. Results show that CPD-30 740 and V1637 Ori are oscillating eclipsing Algol…
We present an analysis of the high-mass eclipsing binary system VV Ori based on photometry from the TESS satellite. The primary star (B1V, 9.5 Msun) shows beta Cephei pulsations and the secondary (B7V, 3.8 Msun) is possibly a slowly-pulsating B star. We detect 51 significant oscillation frequencies, including two multiplets with separations equal to the orbital frequency, indicating that the pulsations are tidally perturbed. We analyse the TESS light curve and published radial velocities to determine the physical properties of the system. Both stars are only the second of their pulsation type …
Chemically peculiar stars in eclipsing binary systems are rare objects that allow the derivation of fundamental stellar parameters and important information on the evolutionary status and the origin of the observed chemical peculiarities. Here we present an investigation of the known eclipsing binary system BD+09 1467 = V680 Mon. Using spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and own observations, we identify the primary component of the system as a mercury-manganese (HgMn/CP3) star (spectral type kB9 hB8 HeB9 V HgMn). Furthermore, photometric time se…
We present the results of our search for variable stars using the long-term Las Cumbres Observatory (LCO) monitoring of white dwarf ZTF J0139+5245 with the two 1.0-m telescope nodes located at McDonald Observatory using the Sinistro imaging instrument. In this search, we find 38 variable sources, of which 27 are newly discovered or newly classified (71%) based on comparisons with previously published catalogs, thereby increasing the number of detections in the field-of-view under consideration by a factor of $\approx$ 2.5. We find that the improved photometric precision per-exposure due to lon…
V1388 Ori is an early-B type detached eclipsing binary whose physical properties have previously been measured from dedicated spectroscopy and a ground-based survey light curve. We reconsider the properties of the system using newly-available light curves from the Transiting Exoplanet Survey Satellite (TESS). We discover two frequencies in the system, at 2.99 d$^{-1}$ and 4.00 d$^{-1}$ which are probably due to beta Cephei or slowly-pulsating B-star pulsations. A large number of additional significant frequencies exist at multiples of the orbital frequency, 0.4572 d$^{-1}$. We are not able to …
Eclipsing binary stars are rare and extremely valuable astrophysical laboratories that make possible precise determination of fundamental stellar parameters. Investigation of early-type chemically peculiar stars in eclipsing binaries provides important information for understanding the origin and evolutionary context of their anomalous surface chemistry. In this study we discuss observations of eclipse variability in six mercury-manganese (HgMn) stars monitored by the TESS satellite. These discoveries double the number of known eclipsing HgMn stars and yield several interesting objects requiri…
We report 11 yr of spectroscopic monitoring of the M-type asymptotic giant branch star eta Gem, a semiregular variable and a known spectroscopic binary with a period of 8.2 yr. We combine our radial velocities with others from the literature to provide an improved spectroscopic orbital solution giving a period of 2979 days, which we then use to predict past times of eclipse. We examine archival photometry from amateur variable star observers, and other sources, and find many instances of dimmings that occurred at the right time. This confirms previous indications that the system is eclipsing, …
Binaries play key roles in determining stellar parameters and exploring stellar evolution models. We build a catalog of 88 eclipsing binaries with spectroscopic information, taking advantage of observations from both the Large Sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) and the Palomar Transient Factory (PTF) surveys. A software pipeline is constructed to identify binary candidates by examining their light curves. The orbital periods of binaries are derived from the Lomb-Scargle method. The key distinguishing features of eclipsing binaries are recognized by a new filter \texti…
Close, compact, hierarchical, multiple stellar systems, i.e., multiples having an outer orbital period from months to a few years, comprise a small, but continuously growing group of the triple and multiple star zoo. Many of them consist of at least one eclipsing pair of stars and, therefore, exhibit readily observable short-term dynamical interactions among the components. Thus, their dynamical and astrophysical properties can be explored with high precision. In this paper we present an overview of the history of the search for additional components around eclipsing binaries from the first se…
A coordinated X-ray and Optical Campaign of the Nearest Massive Eclipsing Binary, $δ$ Orionis Aa: IV. A multiwavelength, non-LTE spectroscopic analysis
The nearby eclipsing stellar system delta Velorum - IV. Differential astrometry with VLT/NACO at the 100 microarcsecond level
上下文delta Vel包含南部天空中最亮的食双星（delta Vel A）和附近距离约0.6英寸的第三颗星（delta Vel B）。Vel B的接近（可用作参考）使其成为特别适合探测食对光中心的天体测量位移的目标。目标。我们获得NACO天体测量观测有两个目标：（1）确认由干涉测量法确定的日食对轨道平面的方向（论文III）和（2）在具有可预测天体测量特性的简单系统上证明窄角自适应光学天体测量的能力。方法.我们测量的角分离矢量之间的食双星Δ Vel A和视觉同伴Δ Vel B从窄带图像在2.17微米获得的VLT/NACO自适应光学系统。根据这些观测结果和我们以前对宽双星delta Vel A-B轨道参数的测定，我们导出了食对在其轨道周期内11个历元的视光心位移。结果我们探测到相对于B的三角洲Vel A对光中心的天体测量摆动，典型的测量精度为每历元~50微弧秒，测量位移的总振幅为~2毫弧秒。结论.探测到的摆动与我们在论文III中提出的模型一致，并证实了Aab轨道平面在天空中的方向。与我们的模型相比，剩余的色散是110微弧秒均方根，我们暂时归因于光度变化的快速旋转的A型组件Aa和/或Ab的BrGamma线。基于这些结果，我们得出结论，在有利的条件下（亮源只有两个可分辨的分量，小的角间距），窄角天体测量与自适应光学上的8米级望远镜可以达到50至100微弧秒的精度。
Multi-site, multi-year monitoring of the oscillating Algol-type eclipsing binary CT Her
我们提出了一个多站点的测光活动在2004-2008年进行的大陵型食双星系统CT她，其中的主要组成部分显示三角洲盾型振荡的结果。我们的数据包括差分光变曲线收集的过滤器B和V已使用威尔逊Devinney（PHOEBE）的方法进行了分析。在识别出一个适当的二元模型并去除最佳匹配的光变曲线解决方案后，我们对剩余的B和V光变曲线进行了傅立叶分析，以研究脉动行为。我们确认存在的快速脉动的主要周期为27.2分钟。高达8个显着的频率与半振幅在3至1毫微克的范围内被检测到，所有这些都令人惊讶地位于频率范围43.5-53.5 C \d。这一结果与主星的有效温度（8200或8700 K）的选择无关，因为双星的光变曲线模型在两种情况下非常相似。这是另一个观测到的复杂频谱的例子，它是一颗正在吸积的盾牌座δ型恒星（在Y Cam之后）。此外，我们证明，这些脉动频率的振幅显示的变化的证据，在时间尺度上短至1-2年，甚至更少。此外，我们的分析考虑到一些最近获得的频谱，从中我们得到了相应的径向速度为2007年至2009年。O-C图的研究表明，进一步监测CTHer的食极小期，将对它的轨道周期演化有新的认识。
BD And is a fairly bright (V = 10.8), active and close (P = 0.9258 days) eclipsing binary. The cyclic variability of the apparent orbital period as well as third light in the light curves indicate the presence of an additional late-type component. The principal aim is the spectroscopic testing of the third-body hypothesis and determination of absolute stellar parameters for both components of the eclipsing binary. First medium and high-resolution spectroscopy of the system was obtained. The broadening-function technique appropriate for heavily-broadened spectra of close binaries was used. The …
K2 Discovery of Young Eclipsing Binaries in Upper Scorpius: Direct Mass and Radius Determinations for the Lowest Mass Stars and Initial Characterization of an Eclipsing Brown Dwarf Binary
Eclipsing time variations (ETVs) in post-common-envelope binaries (PCEBs) were proposed to be due to the time-varying component of the stellar gravitational quadrupole moment. This is suggested to be produced by changes in the stellar structure due to an internal redistribution of angular momentum and the effect of the centrifugal force. We examined this hypothesis and present 3D simulations of compressible magnetohydrodynamics (MHD) performed with the {\sc Pencil Code}. We modeled the stellar dynamo for a solar-mass star with angular velocities of 20 and 30 times solar. We included and varied…
The available minima timings of 14 selected eclipsing binaries (V1297 Cas, HD 24105, KU Aur, GU CMa, GH Mon, AZ Vel, DI Lyn, DK Her, GQ Dra, V624 Her, V1134 Her, KIC 6187893, V1928 Aql, V2486 Cyg) were collected and analyzed. Using the automatic telescopes, surveys, and satellite data, we derived more than 2500 times of eclipses, accompanied with our own ground-based observations. These data were used to detect the period variations in these multiple systems. The eclipse timing variations were described using the third-body hypothesis and the light-time effect. Their respective periods were de…
We present the discovery of a rare system detected in the TESS data showing three different eclipsing-like signals. TIC 452991707 and TIC 452991693 seem to be the second such system on the sky, whose two components separated about 16" are gravitationally bounded, or comprise a co-moving pair. The three periods detected from the TESS data are: PA=1.46155 d, PB=1.77418 d, and PC=1.03989 d, respectively. The A and B periods belong to TIC 452991707, while the C comes from the component TIC 452991693. The pair A shows the deepest eclipses, and its orbit is very slightly eccentric. The third period …
Parenago 1802, a member of the ~1 Myr Orion Nebula Cluster, is a double-lined, detached eclipsing binary in a 4.674 d orbit, with equal-mass components (M_2/M_1 = 0.985 \pm 0.029). Here we present extensive VIcJHKs light curves spanning ~15 yr, as well as a Keck/HIRES optical spectrum. The light curves evince a third light source that is variable with a period of 0.73 d, and is also manifested in the high-resolution spectrum, strongly indicating the presence of a third star in the system, probably a rapidly rotating classical T Tauri star. We incorporate this third light into our radial veloci…
