Proxima is the closest star to the Sun. Recently, astronomers have discovered that it has suddenly produced a huge burst of record-breaking brightness. This could mean that Proxima has undergone dramatic physical changes.
The new observation was made by a team of astronomers Alycia Weinberger of the Carnegie Observatory and Professor Meredith MacGregor of the University of Colorado at Boulder. The observations successfully recorded an extreme flare outburst from Proxima.
Proxima is a red dwarf star with about one-eighth the mass of the Sun and is only four light-years, or about 25 trillion miles, from the center of our solar system. It has at least two planets, one of which is similar to Earth.
Through a collaborative international effort over several months, the research team observed Proxima using nine ground and space telescopes. They discovered the extreme flare on May 1, 2019, and five of the telescopes tracked the timing and energy of the outburst with unprecedented detail.
McGregor said, “When observed from the ultraviolet band, the star’s brightness increased from normal to 14,000 times brighter in a matter of seconds.”
Stellar flares occur when some change in a star’s magnetic field accelerates electrons to near the speed of light. The accelerated electrons interact with the highly ionized plasma that makes up most of the star, causing an outburst and producing radiation across the entire electromagnetic spectrum.
“Proxima is similar in age to the Sun, so for billions of years it has been spewing high-energy radiation toward its planet,” Weinberg said. “Studying these extreme flares with multiple observatories allows us to understand what its planets have endured and how they may have changed.”
Like many red dwarfs (red dwarfs are the most common stars in the Milky Way, and together they host thousands of exoplanets), Proxima is very active.
“If the closest planet to Proxima has life present, it would have to look very different from anything on Earth,” McGregor said. “It would be very difficult for humans to survive on such a planet.”
Weinberg said, “Now we know that these very different observatories operating at very different wavelengths can see the same fast and intense outbursts.”
The new observational technique provides one of the deepest studies of any stellar outburst in the galaxy. Although it doesn’t cause much visible light, it produces huge outbursts in ultraviolet and radio radiation. These signals could help scientists gather more information about how stars produce flares.
It also suggests that the sun’s nearest neighbors may have more surprises in store.
Looking ahead, “there could be more weird types of flares showing different types of physical phenomena that we’ve never considered before.” McGregor concluded.
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