{
  "abstract": "Multiwavelength observations of stellar flares trace the activity of different components of the stars’ outer atmosphere, providing insight into their interactions. In the present paper, we report a superflare from BP Tau, simultaneously observed with the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) satellite and TESS. While we attribute the X-ray flux increase to a magnetically powered flare, the optical light curve likely results from the superposition of the flare and an accretion burst. The X-ray flare has a mean flux of (1.5 −0.04 +0.3 ) × 10 ⁻¹¹ erg cm ⁻² s ⁻¹ in the WXT energy band (0.5−4.0 keV), with e-folding times of 1.7 ± 1.0 ks and 14 ± 5 ks for the rise and decay phase, respectively. The corresponding time-integrated flare energy is (1.0 ± 0.2)×10 ³⁶ erg. The optical flare has an e-folding time of 0.33 ± 0.04 ks for the rise phase, but the data do not constrain the decay timescale. Assuming a decay phase equal to the rise phase, the resulting optical flare energy is (2.8 ± 0.4)×10 ³⁴ erg in the TESS band (∼6000 − ∼10 000 Å), corresponding to a bolometric energy of (1.9 ± 0.3)×10 ³⁵ erg (assuming a blackbody at 11 000 K). The Follow-up X-ray Telescope (FXT) on EP triggered an observation ∼1.5 day after the flare, with a flux of (4.6 −0.5 +0.2 ) × 10 ⁻¹³ erg cm ⁻² s ⁻¹ (0.5−10.0 keV), indicating that BP Tau had returned to quiescence. This work demonstrates the potential of jointly analyzing EP and TESS data for superflares. WXT is expected to detect ∼800 superflares per year, with FXT capable of slewing to the flaring star within ∼3 − 5 minutes. The large field of view of both missions offers us the opportunity to study multiwavelength variability during energetic flares.",
  "abstract_shown": true,
  "affiliations": [
    "Polar Research Institute of China",
    "Key Laboratory for Polar Science, MNR, Polar Research Institute of China",
    "National Astronomical Observatories, Chinese Academy of Sciences",
    "Kavli Institute for Astronomy and Astrophysics, Peking University",
    "Department of Astronomy, Peking University",
    "Hamburger Sternwarte",
    "Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel",
    "INAF–Osservatorio Astronomico di Palermo",
    "Department of Physics, Imperial College London",
    "School of Astronomy and Space Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences",
    "Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University",
    "Department of Physics, the University of Hong Kong",
    "Key Laboratory for Research in Galaxies and Cosmology of Chinese Academy of Sciences, Department of Astronomy, University of Science and Technology of China"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 13,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Xingyu Zhou"
    },
    {
      "affs": [
        2
      ],
      "name": "Mingjun Liu",
      "orcid": "0009-0009-8982-2361"
    },
    {
      "affs": [
        3,
        4
      ],
      "name": "Gregory J. Herczeg",
      "orcid": "0000-0002-7154-6065"
    },
    {
      "affs": [
        5,
        6
      ],
      "name": "P. Christian Schneider",
      "orcid": "0000-0002-5094-2245"
    },
    {
      "affs": [
        7,
        8
      ],
      "name": "Fabio Favata",
      "orcid": "0009-0001-8144-2526"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Chenwei Yang"
    },
    {
      "affs": [
        2,
        9,
        10
      ],
      "name": "Chichuan Jin",
      "orcid": "0000-0002-2006-1615"
    },
    {
      "affs": [
        2
      ],
      "name": "Dongyue Li",
      "orcid": "0000-0002-4562-7179"
    },
    {
      "affs": [
        2,
        9
      ],
      "name": "Xuan Mao",
      "orcid": "0009-0009-8313-1842"
    },
    {
      "affs": [
        11
      ],
      "name": "Yi-Han Iris Yin",
      "orcid": "0000-0002-5596-5059"
    },
    {
      "affs": [
        2,
        9
      ],
      "name": "Minghao Zhang",
      "orcid": "0009-0006-5706-0364"
    },
    {
      "affs": [
        2,
        9
      ],
      "name": "Weimin Yuan",
      "orcid": "0000-0001-8266-3024"
    },
    {
      "affs": [
        0,
        1,
        12
      ],
      "name": "Hongyan Zhou"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5gpe95w3qnh4j.bib",
  "cited_by": 0,
  "doi": "10.1051/0004-6361/202557686",
  "fulltext_url": null,
  "id": "5gpe95w3qnh4j",
  "issns": [
    "0004-6361",
    "1432-0746"
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  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0",
  "metadata_licence": null,
  "native_subjects": [
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      "openalex",
      "3103|Stellar, planetary, and galactic studies"
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  "openalex": "W7204176269",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-02",
  "publisher": "EDP Sciences",
  "ris": "https://research.draconitic.com/paper/5gpe95w3qnh4j.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:18Z",
      "native_id": "10.1051/0004-6361/202557686",
      "source": "crossref",
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  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Stellar, planetary, and galactic studies",
      "subfield": "stellar"
    }
  ],
  "title": "A superflare of BP Tau simultaneously caught by EP X-ray and TESS optical observations",
  "title_text": "A superflare of BP Tau simultaneously caught by EP X-ray and TESS optical observations",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:18Z",
  "url": "https://research.draconitic.com/paper/5gpe95w3qnh4j",
  "venue": "Astronomy & Astrophysics",
  "versions": []
}