Study of Chemically Peculiar Stars-III: High-resolution Spectroscopy and K2 Photometry of New Variables in the Region of M44

Abstract

We aim to carry out a study on the photometric and spectroscopic variabilities of four stars monitored in the Nainital- Cape survey. We analysed the photometric variability of the target stars, HD73135,BD+19° 2045, BD+19° 2046, and TYC 1395- 855-1, using ground-based differential photometric and K2 data. Spectrophotometric and high-resolution spectroscopic data are used to determine the fundamental parameters and chemical abundances. Although all the target are found to be non-variable based on ground-based differential photometry, the analysis of high-precision K2 photometric time-series reveals that HD73135,BD+19° 2045, and BD +19° 2046 are variable. We do not detect photometric variability in TYC 1395-855-1. Our analyses show that the three stars, HD73135, BD+19° 2045,BD+19° 2046, which are non-variable based on ground-based observations exhibit rotational variability in Kepler K2 data while TYC 1395-855-1 remains constant in both data sets. Based on the chemical abundance analysis, HD73135 is an Am star, while BD+19° 2045 is non-Am.