Scientists have noticed the largest eruption ever recorded by the sun’s nearest neighbor, the star Proxima Centauri.
The study, published recently in Astrophysical Journal Letters, was led by CU Boulder and could help shape the hunt for life outside the Earth’s solar system.
CU Boulder astrophysicist Meredith McGregor explained that Proxima Centauri is a small but powerful star. It is only four light-years or more than 20 trillion miles from our own sun and hosts at least two planets, one of which may look like Earth. It is also a “red dwarf”, the name of a class of stars that are unusually small and obscure.
Proxima Centauri has approximately one-eighth the mass of our own sun. But don’t let that fool you.
In their new study, McGregor and colleagues observed the Proxima Centauri for 40 hours using nine telescopes on Earth and in space. In the process, they received a surprise: Proxima Centauri ejected a burst or burst of radiation that began near the surface of a star, which ranks as one of the most brutal seen anywhere in the galaxy.
“The star went from normal to 14,000 times brighter when seen in ultraviolet wavelengths over a period of seconds,” said McGregor, an assistant at the Center for Astrophysics and Space Astronomy (CASA) and the Department of Astrophysics and Planetary Sciences. APS)) in CU Boulder.
The team’s findings suggest a new physics that could change the way scientists think about stellar eruptions. They also do not bode well for any flexible organism brave enough to live near a flying star.
“If there was life on the planet closest to Proxima Centauri, it would look very different from anything on Earth,” McGregor said. “A man on this planet would have a bad time.”
The star has long been a target for scientists hoping to find life beyond Earth’s solar system. Proxima Centauri is nearby, for starters. It also hosts a planet called Proxima Centauri b, which is located in what researchers call a “habitable zone” – a region around a star that has the exact range of temperatures to retain liquid water on the planet’s surface.
But there is a twist, McGregor said: Red dwarfs, which rank among the most common stars in the galaxy, are also unusually lively.
“Many of the exoplanets we’ve discovered so far are around these types of stars,” she said. “But the trick is that they are much more active than our sun. They burn much more often and intensely. “
To see how many Proxima Centaurs explode, she and her colleagues pulled out what was approaching a coup in astrophysics: They aimed nine different instruments at the star for 40 hours over several months in 2019. These eyes include Hubble Space Telescope, the large millimeter Atacama array (ALMA) and NASATransiting Exoplanet Survey Satellite (TES). Five of them recorded the massive torchlight from Proxima Centauri, capturing the event as it produced a wide range of radiation.
“This is the first time we’ve ever had this kind of starburst wavelength coverage,” McGregor said. “You’re usually lucky if you can get two instruments.”
The technique delivered one of the most in-depth anatomies of any star burst in the galaxy.
The event in question was observed on May 1, 2019 and lasted only 7 seconds. Although it did not produce much visible light, it generated a huge surge in both ultraviolet and radio, or “millimeter” radiation.
“In the past, we didn’t know that stars could explode in the millimeter range, so this is the first time we’re looking for millimeter eruptions,” McGregor said.
These millimeter signals, McGregor added, could help researchers gather more information about how stars generate bursts. Scientists now suspect that these bursts of energy occur when magnetic fields near the star’s surface warp and snap with explosive effects.
In general, the observed eruption is approximately 100 times more powerful than any similar radiation observed by the Earth’s sun. Over time, such energy can take away the planet’s atmosphere and even expose life forms to deadly radiation.
This type of torch may not be uncommon with Proxima Centauri. In addition to the big boom in May 2019, researchers recorded many other eruptions in the 40 hours spent watching the star.
“The planets of Proxima Centauri are struck by something like this not once a century, but at least once a day, if not several times a day,” McGregor said.
The findings suggest that there may be more surprises from the nearest satellite of the sun.
“There will probably be even stranger types of torches that demonstrate different types of physics that we haven’t thought about before,” McGregor said.
More on this discovery. read Violent Stellar Flare from the nearest neighboring Sun Record breakthrough.
Reference: “Detection of an extremely short-lived flash by Proxima Centauri with the help of a millimeter through observations with distant ultraviolet rays” by Meredith A. McGregor, Alicia J. Weinberger, RO Park Lloyd, Eugenia Scholnik, Thomas Barclay, Ward C. Howard, Andrew Zeck, Rachel A. Austen, Stephen R. Cranmer, Adam F. Kowalski, Emil Lenz, Alison Youngblood, Anna Estes, David J. Wilner, Ian Forbrich, Anna Hughes, Nicholas M. Lowe, Tara Murphy, Aaron Bowley, and Jamie Matthews, April 21, 2021, Astrophysical Journal Letters.
DOI: 10.3847 / 2041-8213 / abf14c
Other co-authors of the new study are Stephen Cranmer, an associate professor of APS and the Laboratory of Atmospheric and Space Physics (LASP) at CU Boulder; Adam Kowalski, APS and LASP assistant at CU Boulder, also from the National Solar Observatory; Alison Youngblood, LASP researcher; and Anna Estes, a student assistant at APS.
Carnegie Institution of Science, Arizona State University, NASA’s Goddard Space Flight Center, University of Maryland, University of North Carolina at Chapel Hill, University of Sydney, CSIRO Astronomy and Space Sciences, Johns Space Institute, Space Television Institute Hopkins Center for Astrophysics Harvard & Smithsonian and the University of British Columbia also contributed to this study.