The Sun Is Less Active Than Other Solar-like Stars


Light curves of the Sun (A) and three stars from the periodic sample (B-D). (A) Solar TSI data taken at the same epoch as the Kepler observations. The TSI data were detrended by cutting the 4-year time series into 90-day segments, dividing by the median flux and subtracting unity. (B-D) Three examples of stars with different variabilities. The variability ranges Rvar are indicated by the differences between the horizontal red lines before (dashed) and after (solid) correction for the variability dependence on the fundamental parameters. The solid orange lines in (A) mark the maximum solar variability range (Fig. 3 and (13)). The panels have different y-scales.

Magnetic activity of the Sun and other stars causes their brightness to vary. We investigate how typical the Sun's variability is compared to other solar-like stars, i.e. those with near-solar effective temperatures and rotation periods.

By combining four years of photometric observations from the Kepler space telescope with astrometric data from the Gaia spacecraft, we measure photometric variabilities of 369 solar-like stars. Most of the solar-like stars with well-determined rotation periods show higher variability than the Sun and are therefore considerably more active. These stars appear nearly identical to the Sun, except for their higher variability. Their existence raises the question of whether the Sun can also experience epochs of such high variability.

Timo Reinhold, Alexander I. Shapiro, Sami K. Solanki, Benjamin T. Montet, Nathalie A. Krivova, Robert H. Cameron, Eliana M. Amazo-Gomez
Comments: Accepted for publication in Science. 3 (main) + 10 (supplementary) figures
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Journal reference: Science 01 May 2020: Vol. 368, Issue 6490, pp. 518-521
DOI: 10.1126/science.aay3821
Cite as: arXiv:2005.01401 [astro-ph.SR] (or arXiv:2005.01401v1 [astro-ph.SR] for this version)
Submission history
From: Timo Reinhold
[v1] Mon, 4 May 2020 11:36:04 UTC (6,462 KB)
https://arxiv.org/abs/2005.01401
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