The wet flame from the sun’s closest neighbor breaks records

Scientists have observed the largest rocket ever recorded from the sun’s closest neighbor, the star Proxima Centauri.

The research, which appears today in The Astrophysical Journal Letters, was run by the University of Colorado Boulder and could help shape life hunting beyond Earth’s solar system.

Meredith MacGregor, astrophysicist CU Boulder, explained that Proxima Centauri is a small but strong star. It is only four light-years or more than 20 trillion miles from our own sun and is home to 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 weak.

Proxima Centauri has about an eighth of the mass of our own sun. But don’t let that fool you.

In their new study, MacGregor and colleagues observed Proxima Centauri for 40 hours using nine ground and space telescopes. In the process, they received a surprise: Proxima Centauri expelled a rocket or a radiation explosion that begins near the surface of a star, which ranks as one of the most violent seen anywhere in the galaxy.

“The star went from normal to 14,000 times brighter when it was seen in ultraviolet wavelengths within seconds,” said MacGregor, assistant professor at the Center for Astrophysics and Space Astronomy (CASA) and the Department of Astrophysics. and Planetary (APS)) at CU Boulder.

The team’s findings suggest a new physics that could change the way scientists think about stellar flames. It also does not present well to any squishy organism brave enough to live near the volatile star.

“If there were life on the planet closest to Proxima Centauri, it would look very different from anything on Earth,” MacGregor said. “A human being on this planet would feel bad.”

Active stars

The star has long been a target for scientists hoping to find life beyond Earth’s solar system. The next Centauri is nearby, for starters. It also hosts a planet, called Proxima Centauri b, which is in what researchers call the habitable zone – a region around a star that has the correct range of temperatures to house liquid water on the surface of a planet.

But there is a twist, MacGregor said: Red dwarfs, which rank as the most common stars in the galaxy, are also unusually alive.

“A lot of the exoplanets we’ve found so far are around these types of stars,” she said. “But the catch is that they are much more active than our sun. They light up much more frequently and intensely.”

To see how much Proxima Centauri ignites, she and her colleagues managed to approach a coup in the field of astrophysics: they showed nine different stars to the star for 40 hours over several months in 2019. These eyes included the Hubble Space Telescope, the Atacama Large Millimeter Array (ALMA) and NASA’s Transiting Exoplanet Survey Satellite (TESS). Five of them recorded the massive explosion at Proxima Centauri, surprising the event because it produced a wide spectrum of radiation.

“It’s the first time we’ve had this kind of multi-wavelength coverage of a stellar flare,” MacGregor said. “You’re usually lucky if you can get two tools.”

Crispy planet

The technique delivered one of the deepest anatomies of a flame from any star 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 increase in both ultraviolet and radio radiation, or “millimeter” radiation.

“In the past, we didn’t know that stars could ignite within a millimeter, so this is the first time we’re looking for millimeter missiles,” MacGregor said.

These millimeter signals, MacGregor added, could help researchers gather more information about how stars generate missiles. Currently, scientists suspect that these energy explosions occur when the magnetic fields near the surface of a star twist and break with explosive consequences.

In total, the observed rocket was about 100 times stronger than any similar rocket seen from the Earth’s sun. Over time, such energy can remove a planet’s atmosphere and even expose life forms to deadly radiation.

This type of flame may not be a rare event at Proxima Centauri. In addition to the great boom of May 2019, researchers recorded many other eruptions in the 40 hours they spent watching the star.

“The Proxima Centauri planets are hit by something not once a century, but at least once a day, if not several times a day,” MacGregor said.

The findings suggest that there may be more surprises from the sun’s closest companion.

“There will probably be more weird types of rockets that demonstrate different types of physics that we haven’t thought about before,” MacGregor said.