NASA | Swift Catches Mega Flares from a Mini Star
Δημοσιεύτηκε στις 30 Σεπ 2014
On April 23, NASA's Swift satellite
detected the strongest, hottest, and longest-lasting sequence of stellar
flares ever seen from a nearby red dwarf star. The initial blast from
this record-setting series of explosions was as much as 10,000 times
more powerful than the largest solar flare ever recorded.
At its
peak, the flare reached temperatures of 360 million degrees Fahrenheit
(200 million Celsius), more than 12 times hotter than the center of the
sun.
The "superflare" came from one of the stars in a close
binary system known as DG Canum Venaticorum, or DG CVn for short,
located about 60 light-years away. Both stars are dim red dwarfs with
masses and sizes about one-third of our sun's. They orbit each other at
about three times Earth's average distance from the sun, which is too
close for Swift to determine which star erupted.
At 5:07 p.m.
EDT on April 23, the rising tide of X-rays from DG CVn's superflare
triggered Swift's Burst Alert Telescope (BAT). Swift turned to observe
the source in greater detail with other instruments and, at the same
time, notified astronomers around the globe that a powerful outburst was
in progress.
For about three minutes after the BAT trigger, the
superflare's X-ray brightness was greater than the combined luminosity
of both stars at all wavelengths under normal conditions.
The
largest solar explosions are classified as extraordinary, or X class,
solar flares based on their X-ray emission. The biggest flare ever seen
from the sun occurred in November 2003 and is rated as X 45. But if the
flare on DG CVn were viewed from a planet the same distance as Earth is
from the sun and measured the same way, it would have been ranked 10,000
times greater, at about X 100,000.
How can a star just a third
the size of the sun produce such a giant eruption? The key factor is its
rapid spin, a crucial ingredient for amplifying magnetic fields. The
flaring star in DG CVn rotates in under a day, about 30 or more times
faster than our sun. The sun also rotated much faster in its youth and
may well have produced superflares of its own, but, fortunately for us,
it no longer appears capable of doing so.
Read more at: http://www.nasa.gov/content/goddard/n...
This video is public domain and can be downloaded at: http://svs.gsfc.nasa.gov/vis/a010000/...
Like our videos? Subscribe to NASA's Goddard Shorts HD podcast:
http://svs.gsfc.nasa.gov/vis/iTunes/f...
Or find NASA Goddard Space Flight Center on Facebook:
http://www.facebook.com/NASA.GSFC
Or find us on Twitter:
http://twitter.com/NASAGoddard
detected the strongest, hottest, and longest-lasting sequence of stellar
flares ever seen from a nearby red dwarf star. The initial blast from
this record-setting series of explosions was as much as 10,000 times
more powerful than the largest solar flare ever recorded.
At its
peak, the flare reached temperatures of 360 million degrees Fahrenheit
(200 million Celsius), more than 12 times hotter than the center of the
sun.
The "superflare" came from one of the stars in a close
binary system known as DG Canum Venaticorum, or DG CVn for short,
located about 60 light-years away. Both stars are dim red dwarfs with
masses and sizes about one-third of our sun's. They orbit each other at
about three times Earth's average distance from the sun, which is too
close for Swift to determine which star erupted.
At 5:07 p.m.
EDT on April 23, the rising tide of X-rays from DG CVn's superflare
triggered Swift's Burst Alert Telescope (BAT). Swift turned to observe
the source in greater detail with other instruments and, at the same
time, notified astronomers around the globe that a powerful outburst was
in progress.
For about three minutes after the BAT trigger, the
superflare's X-ray brightness was greater than the combined luminosity
of both stars at all wavelengths under normal conditions.
The
largest solar explosions are classified as extraordinary, or X class,
solar flares based on their X-ray emission. The biggest flare ever seen
from the sun occurred in November 2003 and is rated as X 45. But if the
flare on DG CVn were viewed from a planet the same distance as Earth is
from the sun and measured the same way, it would have been ranked 10,000
times greater, at about X 100,000.
How can a star just a third
the size of the sun produce such a giant eruption? The key factor is its
rapid spin, a crucial ingredient for amplifying magnetic fields. The
flaring star in DG CVn rotates in under a day, about 30 or more times
faster than our sun. The sun also rotated much faster in its youth and
may well have produced superflares of its own, but, fortunately for us,
it no longer appears capable of doing so.
Read more at: http://www.nasa.gov/content/goddard/n...
This video is public domain and can be downloaded at: http://svs.gsfc.nasa.gov/vis/a010000/...
Like our videos? Subscribe to NASA's Goddard Shorts HD podcast:
http://svs.gsfc.nasa.gov/vis/iTunes/f...
Or find NASA Goddard Space Flight Center on Facebook:
http://www.facebook.com/NASA.GSFC
Or find us on Twitter:
http://twitter.com/NASAGoddard
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