Science and Exploration

The Give and Take of Mega-Flares From Stars

By Keith Cowing
Press Release
July 5, 2021
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The Give and Take of Mega-Flares From Stars
Lagoon Nebula (left) RCW 120 (right)

These two images contain some of the thousands of stars from a new survey by NASA’s Chandra X-ray Observatory.
This was the largest survey of star formation ever conducted in X-rays, covering some 24,000 individual stars in 40 different regions. The study outlines the link between very powerful flares, or outbursts, from young stars and the impact they could have on planets in orbit around them.

Within this large dataset, scientists identified over a thousand young stars that gave off flares that are vastly more energetic than the most powerful flare ever observed by modern astronomers on the Sun, the “Solar Carrington Event” in 1859. “Super” flares are at least one hundred thousand times more energetic than the Carrington Event and “mega” flares up to 10 million times more energetic.

The Lagoon Nebula (left) is an area about 4,400 light years from Earth in the Milky Way galaxy where stars are actively forming. This field-of-view shows the southern portion of a large bubble of hydrogen gas, plus a cluster of young stars. The Chandra data (purple) have been combined with infrared data (blue, gold, and white) from the Spitzer Space Telescope in this composite image.

A sequence of X-ray images from Chandra show a young star (called “Lagoon 180402.88-242140.0”) in the Lagoon Nebula that experienced a “mega-flare”. This flare was about 250,000 more energetic than the most powerful flare observed by modern astronomers on the Sun, and lasted for about three and a half hours. It was followed by a smaller flare. The total duration of the movie covers almost 23 hours and 27 images are included. This star is only about 1.5 million years old — compared to the Sun’s age of 4.5 billion years — and has a mass about three times that of the Sun. (Note: The apparent changes in the shape of the X-ray source are caused by noise rather than a true change in shape.)

The image on the right shows the star-forming region called RCW 120, which is also in the Milky Way, but slightly farther away at a distance of about 5,500 light years. This view of RCW 120, which has the same wavelengths and colors as the Lagoon composite, contains an expanding bubble of hydrogen gas, about 13 light years across. This structure may be sweeping up material into a dense shell and triggering the formation of stars.

Image credit: X-ray: NASA/CXC/Penn State/K. Getman, et al; Infrared: NASA/JPL/Spitzer Larger image

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