Apsidal Motion and a Light Curve Solution for 13 LMC Eccentric Eclipsing Binaries

Abstract

New CCD observations for thirteen eccentric eclipsing binaries from the Large Magellanic Cloud were carried out using the Danish 1.54-meter telescope located at the La Silla Observatory in Chile. These systems were observed for their times of minima and 56 new minima were obtained. These are needed for accurate determination of the apsidal motion. Besides that, in total 436 times of minima were derived from the photometric databases OGLE and MACHO. The O − C diagrams of minima timings for these B-type binaries were analysed and the parameters of the apsidal motion were computed. The light curves of these systems were fitted using the program PHOEBE, giving the light curve parameters. We derived for the first time the relatively short periods of the apsidal motion ranging from 21 to 107 years. The system OGLE-LMC-ECL-07902 was also analysed using the spectra and radial velocities, resulting in masses 6.8, and 4.4 M ⊙ for the eclipsing components. For one system (OGLE-LMC-ECL-20112), the third-body hypothesis was also used for describing the residuals after subtraction of the apsidal motion, resulting in period of about 22 years. For several systems an additional third light was also detected, which makes these systems suspicious of triplicity.

Apsidal Motion and Absolute Parameters of 21 Early-type Small Magellanic Cloud Eccentric Eclipsing Binaries

“…Kim et al (2018) in their database lists in total 139 eccentric systems where the precession of omega angle is detectable within our Galaxy. However, thanks to recent papers on eccentric binaries in Magel-lanic Clouds (such as Zasche et al (2014), Zasche et al (2015), Hong et al (2015), Hong et al (2016), or the present study) we can surely say that nowadays we know more such systems outside of our own Galaxy! We are grateful to the anonymous referee for his/her fruitful comments and remarks, which greatly improved the whole manuscript.…”

“…This was a subject of several studies during the last couple of years. We have already published a series of papers on apsidal motion in SMC and LMC: Zasche & Wolf (2013), Zasche et al (2014), and Zasche et al (2015). And besides that, the apsidal motion was studied by other authors, most recently (and also most comprehensively) by Hong et al (2016) presenting altogether 90 systems with apsidal motion in SMC, and Hong et al (2015) studying 27 SMC systems.…”

Stability of planetary, single M dwarf, and binary star companions to Kepler detached eclipsing binaries and a possible five body system

“…The out of phase variations in the O-C diagrams for primary and secondary eclipses are likely the result of apsidal motion (Zasche et al 2015). The apsidal motion and rapid eclipse time transitions are features that appear in all of the O-C diagrams of the models when an outer companion as described in Table 1 or Table 2 is present.…”

The first study of the light-travel time effect in massive LMC eclipsing binaries

“…Zasche et al 2015a). All of these binaries are well-detached, slightly eccentric and have orbital periods of the order of couple of days.…”

“…Over the last few years, we performed an analysis of several interesting binaries located in the Magellanic Clouds, which show the apsidal motion (see e.g. Zasche et al 2015a). All of these binaries are well-detached, slightly eccentric and have orbital periods of the order of couple of days.…”