A new value of the period of the classical Cepheid RT Aur on the basis of 456 times of maximum, 1897-2023

The present study collects 456 new times of maximum light of the classical Cepheid RT Aur, covering the period from 1897 to 2022. The O-C diagram resulting from these observations shows that the period given by the GCVS has to be corrected. It results that no strong period variation is found. However, the observed O-C residuals show a long term periodic trend. In the hypothesis of RT Aur being in a binary system, an orbit cannot be deduced from the available astrophysical data.