KIC 3440495: A Rapidly Rotating delta Scuti-gamma Doradus Hybrid Pulsator in a Binary System

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 (rot) = 2.322909(2) day(-1), and the rotational modulation is determined to be caused by starspots. A large frequency separation of Delta nu = 54.5 mu Hz is found by using a Fourier transform, the autocorrelation function, a histogram of frequency differences, and an echelle diagram. We use the large separation to estimate the refined stellar parameters of the star to be v = [239, 279] km s(-1), M = [1.5, 1.65] M (circle dot), R (equator) = [2.03, 2.30] R (circle dot), R (polar) = [1.72, 1.78] R (circle dot), and omega = [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.