On the period determination of ASAS eclipsing binaries

Abstract

Variable stars, or particularly eclipsing binaries, are very essential astronomical occurrence. Surveys are the backbone of astronomy, and many discoveries of variable stars are the results of surveys. All-Sky Automated Survey (ASAS) is one of the observing projects whose ultimate goal is photometric monitoring of variable stars. Since its first light in 1997, ASAS has collected 50,099 variable stars, with 11,076 eclipsing binaries among them. In the present work we focus on the period determination of the eclipsing binaries. Since the number of data points in each ASAS eclipsing binary light curve is sparse, period determination of any system is a not straightforward process. For 30 samples of such systems we compare the implementation of Lomb-Scargle algorithm which is an Fast Fourier Transform (FFT) basis and Phase Dispersion Minimization (PDM) method which is non-FFT basis to determine their period. It is demonstrated that PDM gives better performance at handling eclipsing detached (ED) systems whose variability are non-sinusoidal. More over, using semiautomatic recipes, we get better period solution and satisfactorily improve 53% of the selected object's light curves, but failed against another 7% of selected objects. In addition, we also highlight 4 interesting objects for further investigation.

Light curve solutions of six eclipsing binaries at the lower limit of periods for W UMa stars

“…But the period 0.24914 d of target 5 (see further Table 5) we obtained was around 11 % longer than the previous value (Table 1). This result is not so surprising because the follow-up observations of variable stars from different data bases sometimes reveal different periods than the previous values (Norton et al 2011;Mighell & Plavchan 2013;Lohr et al 2013;Kjurkchieva et al 2014;Mayangsari et al 2014). This is a consequence of the automated frequency analyses of the huge data sets.…”

“…1 The fields of the targets. Mighell & Plavchan 2013;Lohr et al 2013;Kjurkchieva et al 2014;Mayangsari et al 2014). This is a consequence of the automated frequency analyses of the huge data sets.…”

Observations of Eclipsing Binary EPIC 201826968

“…This statement is also reflected in the Astropy and PyAstronomy descriptions of their slightly modified Lomb-Scargle algorithms. (Mayangsari, Priyatikanto, & Putra, 2014) have determined that PDM algorithms are more accurate for systems with non-sinusoidal fits, which may be the case with EPIC 201826968. Therefore, the Lomb-Scargle algorithm's discrepancy may be explained by the non-sinusoidal nature of this system.…”

Variable stars in the residual light curves of OGLE-IV eclipsing binaries towards the Galactic Bulge

“…Consequently, we conclude that the periods of the background signals can be recovered in most cases and the reliability of our algorithms is confirmed by the previous plots. Furthermore, we can state that the PDM method is more suitable for the identification of periodic variables, and it has already been proven very effective at finding EBs (Mayangsari et al 2014;LaCourse et al 2015;Bienias et al 2021;Botan et al 2021), which, based on the distribution of different variable types in the A170, page 4 of 15 original OGLE data, are expected to form a significant part of the background candidates. Nonetheless, all PDM periods were also confirmed by the LS analysis.…”