Using the Australian Square Kilometer Array Pathfinder (ASKAP), the Atacama Large Millimeter / submillimeter Array (ALMA), the NASA / ESA Hubble Space Telescope, NASA’s Transiting Exoplanet Survey Satellite and the du Pont Telescope, astronomers have observed the largest torch. ever recorded by Proxima Centauri, the nearest star neighbor of the Sun and one of the best studied low mass stars.
An artist’s perception of a violent death flash from Proxima Centauri. Image credit: S. Dagnello, NRAO / AUI / NSF.
Proxima Centauri, the smallest member of the Alpha Centauri system, is a star of the M5.5 type, located 4,444 light-years away in the southern constellation of Centaurus.
The star has a measured radius of 14%, the sunbeam, a mass of about 12% sun and an effective temperature of only 3,050 K (2,777 degrees Celsius, or 5,031 degrees Fahrenheit).
Proxima Centauri is 1,000 times less bright than the sun, making it invisible to the naked eye even at its short distance.
“Proxima Centauri is a red dwarf, the name for a class of stars that are extremely small and dull,” said Meredith MacGregor, an astrophysicist in the Department of Astrophysical and Planetary Sciences at the University of Colorado, Boulder.
In a campaign that was carried out over a few months, dr. MacGregor and colleagues Proxima Centauri observed using telescopes on the ground.
On May 1, 2019, they discovered an extreme eruption with five telescopes that tracked its timing and energy in unprecedented detail.
“Now we know that these different observatories operating at different wavelengths can see the same fast, energetic impulse,” said dr. Alycia Weinberger, an astronomer in the Earth & Planets Laboratory at the Carnegie Institution for Science, said.
The flash of 1 May 2019 lasted only 7 seconds and is the brightest ever detected in the millimeter and far ultraviolet wavelengths.
“The star went from normal to 14,000 times brighter when seen in ultraviolet wavelengths for a few seconds,” said Dr. MacGregor said.
“In the past, we did not know that stars could flare up in the millimeter range. So this is the first time we are going to look for millimeter flares.”
“These millimeter signals can help researchers gather more information about how stars generate torches.”
In total, the torch was about 100 times stronger than any similar torch seen from our sun.
“Proxima Centauri’s planets are not hit by something like this once in a century, but at least once a day, even if not several times a day,” said Dr. MacGregor said.
“There will probably be even more strange kinds of torches showing different kinds of physics that we have not thought of before.”
The findings are in the Astrophysical Journal Letters.
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Meredith A. MacGregor et al. 2021. Discovery of an extremely short duration of Proxima Centauri using millimeters to far-ultraviolet observations. ApJL 911, L25; doi: 10.3847 / 2041-8213 / abf14c