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Sun ‘less active’ than similar stars - C C - May 2, 2020

https://cosmosmagazine.com/space/sun-is-less-active-than-similar-stars

EXCERPT: The Sun is less magnetically active and shows less variability in its brightness than similar stars in the galaxy, scientists say. To come to this conclusion, published in the journal Science, they analysed 369 candidate stars selected because they resemble the Sun in decisive properties.

“These stars appear nearly identical to the Sun except for their higher variability. Therefore, we speculate that the Sun could potentially also go through epochs of such high variability,” they write.

... several potential explanations for their observations [...are discussed...], including possibilities that the Sun can have higher variability over long timescales, or differs from similar stars in ways that haven’t yet been recognised.

"It is just as conceivable that stars with known and Sun-like rotation periods show us the fundamental fluctuations in activity the Sun is capable of..." This would mean ... that our star has been unusually feeble over the past 9000 years and that on very large time scales phases with much greater fluctuations are also possible.

In a related Perspective article ... the implications of this [...are considered...]. “The notion that the Sun might reach higher solar activity levels is quite unpleasant news for technological societies... The Sun’s strong activity and the associated solar storms not only produce the beautiful northern and southern lights but also might compromise satellites and power lines, threaten the lives of astronauts in space, and affect Earth’s climate. High stellar activity also has a non-negligible impact on the habitability of planets found around active stars because their atmospheres might be swept out into deep space by such high magnetic activity.”

[...] there is no immediate cause for concern, however, as there is no indication of such solar "hyperactivity" in the immediate future. (MORE - details)


RE: Sun ‘less active’ than similar stars - Catastrophe - May 22, 2020

C C Wrote:https://cosmosmagazine.com/space/sun-is-less-active-than-similar-stars

EXCERPT: The Sun is less magnetically active and shows less variability in its brightness than similar stars in the galaxy, scientists say. To come to this conclusion, published in the journal Science, they analysed 369 candidate stars selected because they resemble the Sun in decisive properties.

“These stars appear nearly identical to the Sun except for their higher variability. Therefore, we speculate that the Sun could potentially also go through epochs of such high variability,” they write.

... several potential explanations for their observations [...are discussed...], including possibilities that the Sun can have higher variability over long timescales, or differs from similar stars in ways that haven’t yet been recognised.

"It is just as conceivable that stars with known and Sun-like rotation periods show us the fundamental fluctuations in activity the Sun is capable of..." This would mean ... that our star has been unusually feeble over the past 9000 years and that on very large time scales phases with much greater fluctuations are also possible.

In a related Perspective article ... the implications of this [...are considered...]. “The notion that the Sun might reach higher solar activity levels is quite unpleasant news for technological societies... The Sun’s strong activity and the associated solar storms not only produce the beautiful northern and southern lights but also might compromise satellites and power lines, threaten the lives of astronauts in space, and affect Earth’s climate. High stellar activity also has a non-negligible impact on the habitability of planets found around active stars because their atmospheres might be swept out into deep space by such high magnetic activity.”

[...] there is no immediate cause for concern, however, as there is no indication of such solar "hyperactivity" in the immediate future. (MORE - details)
Sun ‘less active’ than similar stars

Catastrophe adds:
(In terms of energetic radiation and potential habitability)]

Quote:"Qualitatively the level of energetic radiation should, in principle, be considerably higher than for the Sun," says Solanki.  . . .   . . .   . . . 
However, Solanki is confident that the findings are not necessarily bad news in the search for life elsewhere.
"I would not think that this should be a hindrance to the existence of life," he says. Despite the higher activity of the younger Sun life still evolved on Earth.

As reported in 'Astronomy Now' June 2020 pp 18-19.



RE: Sun ‘less active’ than similar stars - zhangjinyuan - Jul 12, 2020

The solar system is small, but it's amazing