Frequent X-class Far UV Flares from a Young Solar Analog DS Tucanae A

@misc{sextro2026frequent,
  title = {{Frequent X-class Far UV Flares from a Young Solar Analog DS Tucanae A}},
  author = {Tristen Sextro and Kevin France and Vladimir Airapetian and Grace Sweetak and Randall McEntaffer and Kosuke Namekata and Yuta Notsu},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.17683},
  eprint = {2609.17683},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.17683},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Frequent X-class Far UV Flares from a Young Solar Analog DS Tucanae A
AU  - Tristen Sextro
AU  - Kevin France
AU  - Vladimir Airapetian
AU  - Grace Sweetak
AU  - Randall McEntaffer
AU  - Kosuke Namekata
AU  - Yuta Notsu
PY  - 2026
DA  - 2026/09/15
PB  - arXiv
DO  - 10.48550/arxiv.2609.17683
UR  - https://arxiv.org/abs/2609.17683
AB  - The young solar analog DS Tuc A (~45 million years old, spectral type G6V) serves as an excellent proxy to the Sun during early stages of the Earth's evolution. The young Sun's enhanced magnetic activity in the form of X-ray and extreme UV emission, stellar wind, and flares likely affected the magnetospheric and atmospheric environments of early Venus, Earth and Mars. Studies of DS Tuc A help constrain evolution of magnetospheric and atmospheric environments of early Venus, Earth, and Mars and create opportunities to study the impact of flares on the transiting exoplanet, DS Tuc Ab. We analyze ~11 hours of Far-ultraviolet (FUV; 1130 - 1450 mathringA) observations taken by the Hubble Space Telescope Cosmic Origins Spectrograph during late 2023 and early 2024. We find DS Tuc A exhibited 26 flares over ~11.1 hours of observations in the transition region lines Si IV (1394 mathringA + 1402 mathringA), with durations ranging 90 - 960 seconds and FUV absolute energies ranging ~ 10^29 - 10^31 erg over the observed bandpass. Si IV flares are accompanied by increases of other chromospheric and transition region lines, however the strongest Si IV flares show no enhanced coronal emission traced by Fe XXI 1354 mathringA. We present an analysis of each detected flare, including X-ray and bolometric luminosities scaled from FUV flare energies, electron density measurements for the strongest flares, and the Far-UV continuum response to flaring. These results provide constraints on the frequency and energetics of flares comparable to X100-class solar flares and FUV-emitting regions in young solar analogs.
ER  -