KIC 3440495: A Rapidly Rotating δ Scuti-γ Doradus Hybrid Pulsator in a Binary System

DOI: 
10.3847/1538-4357/ac8c30
Publication date: 
08/10/2022
Main author: 
Ma, Shuguo
IAA authors: 
Pascual-Granado, Javier
Authors: 
Ma, Shuguo;Esamdin, Ali;Hernández, Antonio García;Murphy, Simon J.;Lv, Chenglong;Wei, Peng;Rieutord, Michel;Pascual-Granado, Javier;Dang, Fei;Niu, Hubiao;Yang, TaoZhi;Feng, Guojie;Karimov, Rivkat;Tillayev, Yusuf
Journal: 
The Astrophysical Journal
Refereed: 
Yes
Publication type: 
Article
Volume: 
937
Pages: 
80
Abstract: 
In this paper, we study the pulsation properties of KIC 3440495 using Kepler and TESS data. A Fourier analysis of the light curve reveals 24 pulsation modes as well as 29 frequencies associated with rotation. The rotation frequency is derived to be f <SUB>rot</SUB> = 2.322909(2) day<SUP>-1</SUP>, and the rotational modulation is determined to be caused by starspots. A large frequency separation of Δν = 54.5 μHz is found by using a Fourier transform, the autocorrelation function, a histogram of frequency differences, and an échelle diagram. We use the large separation to estimate the refined stellar parameters of the star to be v = [239, 279] km s<SUP>-1</SUP>, M = [1.5, 1.65] M <SUB>⊙</SUB>, R <SUB>equator</SUB> = [2.03, 2.30] R <SUB>⊙</SUB>, R <SUB>polar</SUB> = [1.72, 1.78] R <SUB>⊙</SUB>, and ω = [0.61, 0.77]. The phase modulations of the pulsating frequencies show a long-term trend which may be attributed to an orbital effect of a binary system; hence, the star may be a fast rotating pulsator in a binary system. KIC 3440495 has an amplitude spectrum similar to Altair, and is identified as a potential sister of Altair. Based on studies of Altair, KIC 3330495 is presumably a young star at a similar evolutionary stage.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2022ApJ...937...80M/abstract
ADS Bibcode: 
2022ApJ...937...80M
Keywords: 
Stellar rotation;Stellar pulsations;Starspots;1629;1625;1572