Superflares from red dwarfs are 1,000 times more powerful than solar flares

This could be bad news for life on nearby planets.
Ameya Paleja
Representative image of TRAPPIST-1 red dwarf
Representative image of TRAPPIST-1 red dwarf

Darryl Fonseka/ iStock 

A new study has found that massive, powerful flares from even the quietest stars in our Milky Way are sufficient to strip life-supporting habitats around them. This could have a detrimental effect on civilization or even stop life from taking root in the first place on a planet.

Red dwarfs, formally known as M dwarfs, are the most common stars in the Milky Way and are generally known to be relatively calm. Researchers have been looking at planets around these stars for signs of life.

One such star system is the TRAPPIST-1, which has roughly seven Earth-sized planets, with at least three in a habitable zone. Planets in the habitable zone typically have liquid water on their surface, which is considered a critical requirement for life to begin. The TRAPPIST-1, however, is a red dwarf; a recent study shows that these stars can unleash extremely powerful flares.

Superflares from red dwarfs

A multinational team of researchers looked at observations of 177 red dwarfs made between 2003 and 2020. The data was collected by the European Southern Observatory's 3.6-meter telescope High Accuracy Radial velocity Planet Searcher (HARPS). The extensive data span allowed the researchers to study the long-term variability of the red dwarf stars.

The HARPS instrument looks at the data from a star's chromosphere, the second layer of its atmosphere. Unlike the activity in the star cores that occurs due to nuclear fusion, the action in the chromosphere is driven by magnetic fields.

Superflares from red dwarfs are 1,000 times more powerful than solar flares
A very powerful solar flare can strip the planet of its atmosphere and water

The magnetic fields' arrangement and intensity are responsible for areas of intense activity on the solar surface. For our Sun, these areas appear darker and are called sunspots, which have been found to occur in areas where solar flares are released.

Solar flares from red dwarfs previously measured can be 100-1,000 times more potent than those released by our Sun. In 2019, Proxima Centauri, a red dwarf, let out a flare 14,000 times brighter than its pre-flare brightness.

Solar flares are sometimes followed by hot plasma sent out from the star called coronal mass ejections (CMEs). Its scorching temperatures can blow strip away the atmospheres of planets and even boil away liquid water from the planet's surface, reducing the likelihood of it hosting life.

This could mean that there might be no aliens on planets around such stars. As with all things in science, researchers will further probe these red dwarfs to know if their hypothesis is true.

The research findings will be published in a future publication of the Astronomy & Astrophysics journal. Currently, a draft of the manuscript is available on pre-print serve arXiv.

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