Using the Australian Square Kilometer Array Pathfinder (ASKAP), the Atacama Large Millimeter / Submillimeter Array (ALMA), NASA / ESA Hubble Space Telescope, NASA Transiting Exoplanet Survey Satellite and the Telescope du Pont, astronomers observed the largest eruption ever recorded from Proxima Centauri , the closest stellar neighbor of the Sun and one of the best studied low-mass stars.
An artist’s conception of a violent stellar flame from Proxima Centauri. Image credit: S. Dagnello, NRAO / AUI / NSF.
Proxima Centauri, the smallest member of the Alpha Centauri system, is an M5.5 star located 4,244 light-years away in the southern constellation Centaurus.
The star has a measured radius of 14% of the Sun’s radius, a mass of about 12% of the sun and an effective temperature of only about 3,050 K (2,777 degrees Celsius or 5,031 degrees Fahrenheit).
The next Centauri is 1,000 times less bright than the Sun, which even at close range makes it invisible to the naked eye.
“Proxima Centauri is a red dwarf, the name of a class of stars that are unusually small and weak,” said Meredith MacGregor, an astrophysicist in the Department of Astrophysics and Planetary Sciences at the University of Colorado, Boulder.
In a campaign over several months, Dr. MacGregor and colleagues observed Proxima Centauri using terrestrial and space telescopes.
They discovered an extremely evasive event on May 1, 2019, with five telescopes that traced its time and energy in unprecedented detail.
“We now know that these very different observatories that operate at very different wavelengths can see the same rapid energy impulse,” said Dr. Alycia Weinberger, an astronomer at the Earth and Planetary Laboratory at Carnegie Institution for Science.
The May 1, 2019 flame lasted only 7 seconds and is the brightest ever detected in distant millimeter and ultraviolet wavelengths.
“The star went from normal to 14,000 times brighter when it was seen at ultraviolet wavelengths within seconds,” said Dr. MacGregor.
“In the past, I didn’t know that stars could flare within a millimeter’s range, so this is the first time we’re looking for millimeter missiles.”
“These millimeter signals could help researchers gather more information about how stars generate missiles.”
In all, the rocket was about 100 times more powerful than any similar rocket seen from our Sun.
“The Proxima Centauri planets are hit by something not once a century, but at least once a day, if not several times a day,” said Dr. MacGregor.
“There will probably be more strange types of flames that demonstrate different types of physics that we haven’t thought about before.”
The findings were published in Astrophysical Journal Letters.
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Meredith A. MacGregor et al. 2021. Discovery of an extremely short-lived eruption from Proxima Centauri using the millimeter through distant ultraviolet observations. ApJL 911, L25; doi: 10.3847 / 2041-8213 / abf14c