举办单位：理论物理研究所

负责人姓名：牛家树

电话：0351-7018709

活动主题：K2 Photometry on Oscillation Mode Variability: The New Pulsating Hot B Subdwarf Star EPIC 220422705

形式：线下学术报告

活动内容摘要：

We present an analysis of oscillation mode variability in the hot B subdwarf star EPIC 220422705, a new pulsator discovered from ∼78 days of K2 photometry. The high-quality light curves provide a detection of 66 significant independent frequencies, from which we identified nine incomplete potential triplets and three quintuplets. Those g- and p-multiplets give rotation periods of ∼36 and 29 days in the core and at the surface, respectively, potentially suggesting a slightly differential rotation. We derived a period spacing of 268.5 s and 159.4 s for the sequence of dipole and quadrupole modes, respectively. We characterized the precise patterns of amplitude and frequency modulations (AM and FM) of 22 frequencies with high enough amplitude for our science. Many of them exhibit intrinsic and periodic patterns of AM and FM, with periods on a timescale of months as derived by the best fitting and Markov Chain Monte Carlo test. The nonlinear resonant mode interactions could be a natural interpretation for such AMs and FMs after other mechanisms are ruled out. Our results are the first step to building a bridge between mode variability from K2 photometry and the nonlinear perturbation theory of stellar oscillation.

主讲人基本情况：

马晓宇，就读于北京师范大学天文系，天体物理学专业，19级硕博连读生，现以第一作者发表一篇SCI论文，作为合作者参与到多篇SCI论文当中。研究方向涉及到星震学、振幅与频率调制、测光（Kepler/K2、TESS），光谱处理（LAMOST）和双星。

听众范围：物理学科师生

举办时间：2023-02-26

举办地点：理论物理研究所报告厅

报告类型：理科类