Discovery of multiple p-mode pulsation frequencies in the roAp star, HD 86181

Shi, Fangtian; Kurtz, D. W.; Holdsworth, Daniel Luke; Saio, Hideyuki; Cunha, M. S.; Zhang, Huawei; Fu, Jian-Ning; Handler, G.

doi:10.1093/mnras/stab2144

Cited by 3 publications

(1 citation statement)

References 63 publications

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“…The first harmonic f l1 is the highest peak at the low frequency of KLCD. The doublehumped wave of the phase diagram shown in Figure 3 may result in that the first harmonic hashigher amplitude than the frequency f l2 has (Shi et al 2021). The five related frequencies are marked as f l1 , f l2 , f l3 , f l4 , and f l5 in Table 4.…”

Section: Frequencies In Klcdmentioning

confidence: 99%

KIC 5768203: A δ Sct Pulsator Modulated by Rotation and Spots

Esamdin

et al. 2022

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We perform a detailed analysis of the Kepler target KIC 5768203 based on the Kepler and Transiting Exoplanet Survey Satellite (TESS) data. Three independent frequencies are detected by Fourier analysis of the Kepler long-cadence data: two pulsation frequencies f P0 = 7.807874(2) day−1 and f P1 = 9.970035(6) day−1, which have amplitudes below 1.4 mmag in the Kepler band, and one modulation frequency f rot = 0.45813(1) day−1. Based on a period ratio of 0.7803, f P0 and f P1 are supposed to be radial frequencies. However, further confirmation is needed. Based on the triplets and phase variations of the two pulsation frequencies, the star is possibly a δ Sct pulsator in a binary system. The modulation frequency f rot and its four harmonics could be attributed to the stellar rotation and surface spots. With the rotation frequency f rot, the rotation velocity of the star is estimated to be 75(3) km s−1. By analyzing the phase diagram without pulsations, it is inferred that there are starspots (or clusters of starspots) of large area on the surface of KIC 5768203. These starspots are slowly evolving in position and brightness over the course of the Kepler long-cadence observations. The finding of the rotation frequency in the TESS data implies the long-term presence of starspots on the surface of KIC 5768203.

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Section: Frequencies In Klcdmentioning

confidence: 99%

KIC 5768203: A δ Sct Pulsator Modulated by Rotation and Spots

Esamdin

et al. 2022

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Pulsations of Three Rapidly Oscillating Ap Stars TIC 96315731, TIC 72392575, and TIC 318007796

Zhong,

Shen,

Zhu

et al. 2024

Res. Astron. Astrophys.

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We analyze the frequencies of three known roAp stars, TIC 96315731, TIC 72392575, and TIC 318007796, using the light curves from the Transiting Exoplanet Survey Satellite (TESS). For TIC 96315731, the rotational and pulsational frequencies are 0.1498360 d-1 and 165.2609 d-1, respectively. In the case of TIC 72392575, the rotational frequency is 0.25551 d-1. We detect a quintuplet of pulsation frequencies with a center frequency of 135.9233 d-1, along with two signals within the second pair of rotational sidelobes of the quintuplet separated by the rotation frequency. These two signals may correspond to the frequencies of a dipole mode. In TIC 318007796, the rotational and pulsational frequencies are 0.2475021 d-1, 192.73995 d-1, and 196.33065 d-1, respectively. Based on the oblique pulsator model, we calculate the rotation inclination (i) and magnetic obliquity angle (β) for the stars, which provides the geometry of the pulsation modes. Combining the phases of the frequency quintuplets, the pulsation amplitude and phase modulation curves, and the results of spherical harmonic decomposition, we conclude that the pulsation modes of frequency quintuplets in TIC 96315731, TIC 72392575, and TIC 318007796 correspond to distorted dipole mode, distorted quadrupole mode, and distorted dipole mode, respectively.

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TESS Cycle 2 observations of roAp stars with 2-min cadence data

Holdsworth,

Cunha,

Lares-Martiz

et al. 2023

Monthly Notices of the Royal Astronomical Society

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We present the results of a systematic search of the Transiting Exoplanet Survey Satellite (TESS) 2-min cadence data for new rapidly oscillating Ap (roAp) stars observed during the Cycle 2 phase of its mission. We find seven new roAp stars previously unreported as such and present the analysis of a further 25 roAp stars that are already known. Three of the new stars show multiperiodic pulsations, while all new members are rotationally variable stars, leading to almost 70 per cent (22) of the roAp stars presented being α2 CVn-type variable stars. We show that targeted observations of known chemically peculiar stars are likely to overlook many new roAp stars, and demonstrate that multiepoch observations are necessary to see pulsational behaviour changes. We find a lack of roAp stars close to the blue edge of the theoretical roAp instability strip, and reaffirm that mode instability is observed more frequently with precise, space-based observations. In addition to the Cycle 2 observations, we analyse TESS data for all-known roAp stars. This amounts to 18 further roAp stars observed by TESS. Finally, we list six known roAp stars that TESS is yet to observe. We deduce that the incidence of roAp stars amongst the Ap star population is just 5.5 per cent, raising fundamental questions about the conditions required to excite pulsations in Ap stars. This work, coupled with our previous work on roAp stars in Cycle 1 observations, presents the most comprehensive, homogeneous study of the roAp stars in the TESS nominal mission, with a collection of 112 confirmed roAp stars in total.

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Discovery of multiple p-mode pulsation frequencies in the roAp star, HD 86181

Cited by 3 publications

References 63 publications

KIC 5768203: A δ Sct Pulsator Modulated by Rotation and Spots

KIC 5768203: A δ Sct Pulsator Modulated by Rotation and Spots

Pulsations of Three Rapidly Oscillating Ap Stars TIC 96315731, TIC 72392575, and TIC 318007796

TESS Cycle 2 observations of roAp stars with 2-min cadence data

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