From University of Sydney (AU) via EarthSky: “Space weather in Proxima’s vicinity dims hopes of habitable worlds”

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From University of Sydney (AU)




December 23, 2020
Paul Scott Anderson

Astronomers used radio waves to study conditions in the vicinity of Proxima Centauri, the nearest star to our sun. The results suggest Proxima’s 2 known planets are likely bathed in intense radiation from this star, casting doubt on the planets’ potential for life.

Centauris Alpha Beta Proxima, 27 February 2012. Skatebiker.

Artist’s concept of huge flares on Proxima Centauri, which unleash ionizing radiation. This radiation could be dangerous for any possible life on planets orbiting close to the star. Image via NASA/ ESA/ G. Bacon (STScI)/

This month, even as some astronomers are talking about a possible mystery radio signal from Proxima Centauri – a signal of interest to astronomers who search for intelligent life beyond Earth – other astronomers are talking about space weather in the vicinity of this star, which is the nearest star to our sun. Space weather in Proxima’s vicinity, they are saying, might make life on its planets difficult or even impossible.

What is space weather?

When we hear about weather, we might think of Earth – sun, clouds, rain, wind and so on – or we might think about conditions on other planets or moons that have atmospheres. Space weather isn’t about that. It’s a sort of “weather” that originates in stars, including our own sun, and that permeates the space near a star. Space weather consists of ionizing radiation released during flares on the sun, or other stars.

Space weather. Credit: NASA.

The radiation can be deadly for any life forms that may exist on distant planets. That’s especially true, astronomers say, for red dwarf stars, which have more frequent flares than our sun. Red dwarf stars can be very volatile. Proxima Centauri is a red dwarf star.

Astronomers at the University of Sydney in Australia announced the new study on December 10, 2020. These researchers used radio waves to detect and probe the space weather in Proxima’s vicinity. Our sun’s nearest neighbor at only 4.2 light-years away, Proxima is known to have at least two planets orbiting it. One, Proxima Centauri b, is almost the same mass as Earth and the other, Proxima Centauri c, is about seven times more massive. Proxima Centauri b also orbits within its stars’ habitable zone, where temperatures might allow liquid water to exist on planet’s surface. Sounds promising, right? But the new findings about flares on stars like Proxima suggests a grim prospect for life on the planets in this system.

The researchers published their peer-reviewed findings in The Astronomical Journal on December 9.

These astronomers worked with CSIRO’s Australian Square Kilometre Array Pathfinder (ASKAP) telescope in Western Australia and the Zadko Telescope at the University of Western Australia, as well as other instruments. Tara Murphy of the University of Sydney helped lead the study.

Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

The Zadko telescope is used by staff at the University of Western Australia and scientists in France. Credit: ABC Radio Perth: Emma Wynne.

See the full article here .


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