LEIA Discovery of the Longest-lasting and Most Energetic Stellar X-Ray Flare Ever Detected
Abstract The Lobster Eye Imager for Astronomy (LEIA) detected a new X-ray transient on 2022 November 7, identified as a superflare event occurring on a nearby K-type giant star HD 251108. The flux increase was also detected in follow-up observations at X-ray, UV, and optical wavelengths. The flare lasted for about 40 days in soft X-ray observations, reaching a peak luminosity of ∼1.1 × 10 34 erg s −1 in 0.5–4.0 keV, which is roughly 60 times the quiescent luminosity. Optical brightening was observed for only one night. The X-ray light curve is well described by a double fast rise and exponential decay model, attributed to the cooling process of a loop arcade structure formed subsequent to the initial large loop with a half-length of ∼1.9 × 10 12 cm. Time-resolved X-ray spectra were fitted by a four-temperature apec model (with three components being the quiescent background), showing significant evolution of plasma temperature and emission measure over time. The estimated energy released in the LEIA band is ∼3 × 10 39 erg, suggesting that this is likely the most energetic X-ray stellar flare with the longest duration detected to date.
Authors
- Jujia Zhang (ORCID: https://orcid.org/0000-0002-8296-2590)
- Weimin Yuan (ORCID: https://orcid.org/0000-0001-8266-3024)
- L. P. Xin (ORCID: https://orcid.org/0000-0002-9422-3437)
- Huaqiu Liu
- Chichuan Jin (ORCID: https://orcid.org/0000-0002-2006-1615)
- Fabio Favata (ORCID: https://orcid.org/0009-0001-8144-2526)
- Dongyue Li (ORCID: https://orcid.org/0000-0002-4562-7179)
- He‐Yang Liu (ORCID: https://orcid.org/0000-0002-2412-5751)
- Yonghe Zhang (ORCID: https://orcid.org/0000-0002-3817-8694)
- Jianrong Shi (ORCID: https://orcid.org/0000-0002-0349-7839)
- Song Wang (ORCID: https://orcid.org/0000-0003-3116-5038)
- Xu Ding (ORCID: https://orcid.org/0000-0002-2427-161X)
- Tuo Ji (ORCID: https://orcid.org/0000-0002-9000-4915)
- Haiwu Pan (ORCID: https://orcid.org/0000-0001-5249-2797)
- Guiping Zhou (ORCID: https://orcid.org/0000-0001-8228-565X)
- Yanfeng Dai (ORCID: https://orcid.org/0000-0003-3648-9429)
- Xiaofeng Zhang (ORCID: https://orcid.org/0000-0002-3566-9084)
- Dingrong Xiong (ORCID: https://orcid.org/0000-0002-6809-9575)
- Kaifan Ji (ORCID: https://orcid.org/0000-0001-8950-3875)
- A. J. Castro‐Tirado (ORCID: https://orcid.org/0000-0003-2999-3563)
- Licai Deng (ORCID: https://orcid.org/0000-0001-9073-9914)
- Zhiming Cai (ORCID: https://orcid.org/0009-0005-2072-3075)
- Jian-Guo Wang (ORCID: https://orcid.org/0000-0003-4156-3793)
- Chen Zhang (ORCID: https://orcid.org/0000-0003-2445-0754)
- Jing Wang (ORCID: https://orcid.org/0000-0002-6880-4481)
- Shuai Liu (ORCID: https://orcid.org/0000-0001-5193-1727)
- Wenxin Wang (ORCID: https://orcid.org/0000-0002-5053-0611)
- Wenda Zhang (ORCID: https://orcid.org/0000-0001-5647-7762)
- Mingjun Liu (ORCID: https://orcid.org/0009-0009-8982-2361)
- Jun Lin (ORCID: https://orcid.org/0000-0002-3326-5860)
- Hua-Li Li (ORCID: https://orcid.org/0000-0002-7457-4192)
- Xuan Mao
- Hui Sun (ORCID: https://orcid.org/0000-0002-7564-0809)
- Xinlin Zhao (ORCID: https://orcid.org/0009-0005-5459-7433)
- Jianyan Wei
- Xiaojin Sun
- Huaqing Cheng
- Shengli Sun
- Ya-Juan Lei (ORCID: https://orcid.org/0000-0001-9510-3181)
- Zhixing Ling (ORCID: https://orcid.org/0009-0008-7068-0693)
- Jingxiu Wang (ORCID: https://orcid.org/0000-0003-2544-9544)
- Donghua Zhao
- Yuan Liu (ORCID: https://orcid.org/0000-0001-6676-6875)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-02-20
- DOI
- https://doi.org/10.3847/1538-4357/ada698
- Citations
- 3
- Primary Topic
- Gamma-ray bursts and supernovae
- Type
- article
- Field-Weighted Citation Impact
- 3.46