English

Variability of magnetic hot stars from the TESS observations

Solar and Stellar Astrophysics 2023-08-31 v1

Abstract

Magnetic hot stars refer to the stars, which effective temperatures approximately in the range from 7,000 to 50,000 K, and with large-scale globally organized magnetic fields. These magnetic fields exhibit strengths ranging from tens of Gauss to tens of kilo-Gauss. They are key in understanding the effects caused by magnetic fields in the stellar evolution. However, there are only three magnetic hot stars studied via a combination of spectropolarimetric and asteroseismic modeling. Combined with Transiting  Exoplanet  Survey  Satellite  (TESS)Transiting\;Exoplanet\;Survey\;Satellite\;(TESS) 1-56 sectors data sets, we provided a photometric variability and stochastic low frequency (SLF) variability study of 118 magnetic hot stars. 9 new rotating variable stars are identified. Using the Bayesian Markov Chain Monte Carlo (MCMC) framework, we fitted the morphologies of SLF variability for magnetic hot stars. Our analysis reveals that the magnetic hot stars in our sample have γ<5.5\gamma < 5.5 with the vast majority having 1γ31 \leq \gamma \leq 3. The νchar\nu_{\rm char} is primarily in the ranges of 0  d1<νchar<6.3  d10\;\text{d}^{-1} < \nu_{\rm char} < 6.3\;\text{d}^{-1}. The amplitude of SLF variability, logα0\alpha_{\rm 0}, shows a dominant distribution ranging from 0.8 to 3. No significant correlations are observed between the luminosity and fitting parameters, suggesting no clear dependence of SLF variability on stellar mass for our sample of magnetic hot stars with masses between approximately 1.5M<M<20M1.5 M_{\odot}< M < 20 M_{\odot}. We found a significant negative correlation between the BpB_{\rm p} and νchar\nu_{char}. This suppression effect of magnetic fields on νchar\nu_{\rm char} may be a result of their inhibition of macroturbulence.

Keywords

Cite

@article{arxiv.2308.15687,
  title  = {Variability of magnetic hot stars from the TESS observations},
  author = {Dong-Xiang Shen and Gang Li and Iskandar Abdusamatjan and Jian-Ning Fu and Chun-Hua Zhu and Jin-Long Yu and Yu Zhang and Guo-Liang Lv and Nan-Nan Zhai and Jin-Zhong Liu},
  journal= {arXiv preprint arXiv:2308.15687},
  year   = {2023}
}

Comments

46 pages, 25 figures, Accepted by ApJ