Discovered the Long-term Variation of the Variable Star CzeV818

Abstract

In this study we describe the reclassification of the variable star CzeV818, discovered in 2015 by Pavel Cagas (Skarka et al. 2017), which was cataloged as a delta Scuti variable. From the photometric study performed with the telescopes of the SSV-UAI-GRAV (Unione Astrofili Italiani, Variable Star Section), All-Sky Automated Survey for Supernovae (Kochanek et al. 2017) (ASAS-SN) and Zwicky Transient Facility (Masci et al. 2019) (ZTF) surveys and the G-spectrum obtained from Gaia DR3 (Gaia Collaboration et al. 2023) (Astrophysical parameters inference system, Apsis) data, it was possible to understand that the luminous variation was not due to pulsations but due to spots (as discussed in Roxburgh 1964), present in the photosphere with a cycle of 0.402533 day (9.66 hr). Analyzing the long-term data present in the ASAS-SN and ZTF surveys, it was possible to determine a cycle of 2900 days (7.95 yr), which is similar to the solar cycle.