English

When will T Coronae Borealis next erupt as a nova? Constraints from recurrence, orbital phase, and accretion-state evolution

High Energy Astrophysical Phenomena 2026-07-16 v1

Abstract

T Coronae Borealis (T CrB) is the nearest symbiotic recurrent nova and is now intensively monitored for its next eruption. We combine three constraints on the eruption time: historical recurrence, orbital phase, and recent accretion-state evolution. Conditioning on no eruption by 2026 July 11, the three effective historical intervals give illustrative survival-conditioned probabilities of 30.2\% for the rest of 2026 and 56.9\% within the following year; these are empirical indicators, not physical prediction probabilities. The four adopted historical eruption phases do not select a unique ignition phase, but form two loose pairs near ϕ0.44\phi\simeq0.44 and ϕ0.62\phi\simeq0.62, used here only as monitoring windows. The 1946 pre-eruption dip is difficult to explain by either a pure accretion-rate decline or standard dust extinction, and may have involved both accretion restructuring and source-dependent obscuration. If the renewed 2026 decline is the true pre-1946 analogue, an eruption around 2026 December remains plausible. Conversely, if post-2024 brightness remains below the 2014--2023 high state, an accretion-deficit estimate gives an earliest lower limit near 2029 May. The data therefore support conditional monitoring windows, not a unique date. These are conditional diagnostic scenarios rather than competing point predictions; the eventual eruption epoch will test their underlying assumptions.

Keywords

Cite

@article{arxiv.2607.15245,
  title  = {When will T Coronae Borealis next erupt as a nova? Constraints from recurrence, orbital phase, and accretion-state evolution},
  author = {Songpeng Pei and Xiaowan Zhang and Renzhi Su and Ziwei Ou and Yongzhi Cai and Qiang Li and Yu Liu and Xiaoqin Ren and Taozhi Yang},
  journal= {arXiv preprint arXiv:2607.15245},
  year   = {2026}
}

Comments

7 pages, 1 figure, Accepted for publication in Monthly Notices of the Royal Astronomical Society Letter (MNRAS Letter)