Observation of a Possible Superflare on Proxima Centauri

The full undetrended data set for photometry of Proxima Centauri on UTC 2017.07.01 from Mt. Kent Obser- vatory versus barycentric Julian day. The measurements with our CDK700 telescope were processed with AstroImageJ. Three other nights acquired with the same instrumentation are shown offset by 0.05 relative flux and by time to illustrate the normal photometry of Proxima Centauri.

We report the observation on UT 2017.07.01 of an unusually powerful flare detected in near-infrared continuum photometry of Proxima Centauri.

During a campaign monitoring the star for possible exoplanet transits, we identified an increase in Sloan i' flux leading to an observed peak at BJD 2457935.996 that was at least 10\% over pre-flare flux in this band. It was followed by a 2-component rapid decline in the first 100 seconds that became a slower exponential decay with time constant of 1350 seconds.

A smaller flare event 1300 seconds after the first added an incremental peak flux increase of 1% of pre-flare flux. Since the onset of the flare was not fully time-resolved at a cadence of 62 seconds, its actual peak value is unknown but greater than the time-average over a single exposure of 20 seconds. The i' band is representative of broad optical and near-IR continuum flux over which the integrated energy of the flare is 100 times the stellar luminosity.

This meets the criteria that established the concept of superflares on similar stars. The resulting implied ultraviolet flux and space weather could have had an extreme effect on the atmospheres of planets within the star's otherwise-habitable zone.

John F. Kielkopf, Rhodes Hart, Bradley D. Carter, Stephen C. Marsden
(Submitted on 15 Apr 2019)

Comments: 5 pages, 2 figures
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:1904.06875 [astro-ph.SR] (or arXiv:1904.06875v1 [astro-ph.SR] for this version)
Submission history
From: John Kielkopf
[v1] Mon, 15 Apr 2019 06:44:01 UTC (160 KB)
https://arxiv.org/abs/1904.06875
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