This tutorial contains step-by-step instructions for finding the orbital period of the Algol-type eclipsing binary (EA) GSC 04433-00065

The orbital period, or time span between two primary minima, is very regular over moderate periods of time (months to years), being determined by the time it takes for the two components of the system to once orbit around each other. Most Algol variables are quite close binaries, and therefore their periods are short, typically a few days. 

GSC 04433-00065 was detected by Sebastian Otero in 2020. It has a magnitude range from V=11.74 - 12.30 and a period of 26.35150 d. It is a very eccentric EA variable star. We will use the GSC 04433-00065 ASAS-SN1 light curve, which we will learn to create in Tutorial 12, to determine the orbital period.

We will discuss two methods for determining the orbital period: the EASolver method and the EEBLS method. You are already familiar with EEBLS from Tutorial 6. Comparing both methods, you will notice that EEBLS in some cases is superior to EASolver, while in other situations EASolver outperforms EEBLS.

(1) We acknowledge with thanks the ASAS-SN team for making their light curves available on the Internet. See Shappee et al. (2014) and Kochanek et al. (2017)