A team of astronomers from India and Nepal have detected that stars also go through a midlife crisis.
During this time they experience dramatic breaks in their activity, rotational rates, transitioning into an inactive phase.
The study provides a new technique to measure the age of stars past their middle age.
What happens when stars reach midlife?
Spread over billions of years, the development leads to a decline in the numbers of sunspots, flares, outbursts, and similar phenomena in the atmospheres of stars.
These developments are directly linked to the strength of their magnetic fields.
Researchers using the dynamo models of magnetic field generation in stars found that at about the age of the Sun the magnetic field generation mechanism of stars suddenly becomes sub-critical or less efficient.
The falling field generations lead to two activity states a low activity mode and an active mode.
A middle-aged star like the Sun can often switch to the low activity mode resulting in drastically reduced angular momentum losses by magnetized stellar winds.
Significance of the study
This hypothesis of sub-critical magnetic dynamos of solar-like stars provides a self-consistent, unifying physical basis for a diversity of solar-stellar phenomena, such as why stars beyond their midlife do not spin down as fast as in their youth, the breakdown of stellar gyrochronology relations et.
The recent findings suggesting that the Sun maybe transitioning to a magnetically inactive future.
It will also shed light on recent observations indicating that the Sun is comparatively inactive.
Do you know?
The Sun is currently a main sequence star and will remain so for another 4-5 billion years.
It will then expand and cool to become a red giant, after which it will shrink and heat up again to become a white dwarf.
The white dwarf star will run out of nuclear fuel and slowly cool down over many billions of years.
