Period–Luminosity Relationship for δ Scuti Stars Revisited

Abstract

The Gaia DR3 parallax approach was used to estimate the absolute parameters of 2375 δ Scuti stars from the ASAS catalog. The selected stars have a variety of observational characteristics, with a higher than 80% probability of being δ Scuti stars. We have displayed all the stars in the Hertzsprung–Russell diagram along with the δ Scuti instability strip, the Zero Age Main Sequence and the Terminal Age Main Sequence. Then, we determined which fundamental and overtone modes each star belongs to using pulsation constant (Q) calculations. In addition, we evaluated the parameters in the Q calculation equation using three machine learning methods, which showed that surface gravity and temperature have the greatest effect on its calculation. The Period–Luminosity (P-L) relationship of the δ Scuti stars was also revisited. Eventually, using least squares linear regression, we made four linear fits for fundamental and overtone modes and updated their relationships.