Asteroseismology of HD 23734, HD 68703, and HD 73345 using K2–TESS space-based photometry and high-resolution spectroscopy
Year: 2025
Type: article
Abstract: ABSTRACT In this paper, we present a comprehensive study of three stars, HD 23734, HD 68703, and HD 73345, which were previously observed as chemically peculiar candidates within the Nainital-Cape survey and reported as null results for the pulsational variability. Frequency analyses of K2 and TESS time-series photometric data reveal the co-existence of rotational modulation and pulsation. We use the spectrum synthesis technique to determine fundamental parameters and chemical composition, which shows that all the three stars are likely to be chemically normal. The evolutionary status of the target stars corresponds to the main-sequence phases and places them within the $\delta$ Scuti instability strip of the Hertzsprung–Russell diagram. The line profile variability is observed in all three stars, especially intriguing in HD 68703 and a typical signature of the non-radial pulsation, demands further detailed examination. Using TESS photometry, we identified the radial modes of orders n = 3 and 4 for HD 23734, n = 1, 3, and 4 for HD 68703, and n = 3, 4, and 5 for HD 73345. In addition to the presence of pulsation and rotation, HD 73345 exhibits a steady increase in radial velocity that we interpret as the star being likely to be part of a long-period binary system. Finally, we propose an extended campaign aimed for the in-depth spectroscopic and spectropolarimetric study of selected pulsating stars monitored under the Nainital-Cape survey project.
Institutions: Aryabhatta Research Institute of Observational Sciences, M.J.P. Rohilkhand University, National Astronomical Research Institute of Thailand, Mbarara University of Science and Technology, Kyambogo University, Royal Observatory of Belgium, University of Liège, KU Leuven, National Institute of Technology Rourkela, Indian Institute of Astrophysics, Gauhati University, University of Calicut
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
Funders: National Aeronautics and Space Administration, European Commission, Department of Science and Technology, Ministry of Science and Technology, India, Chinese Academy of Sciences, Fonds De La Recherche Scientifique - FNRS, Belgian Federal Science Policy Office, Fonds Wetenschappelijk Onderzoek, KU Leuven, European Southern Observatory, Uppsala Universitet, National Development and Reform Commission, Vlaamse regering, Instituto de Astrofísica de Canarias, Science and Engineering Research Board, National Astronomical Observatories, Chinese Academy of Sciences
OpenAlex ID: W4413849251