Data from the SOHO spacecraft – a joint NASA and ESA project – has shown astronomers powerful starquakes rippling around the Sun in the wake of mighty solar flares.
Solar flares can cause sunquakes -although exactly how is still mystery
Solar flares that explode above the Sun’s surface often cause sunquakes to undulate around the Sun and observing these can provide valuable information about the Sun’s interior conditions. The joint ESA-NASA Solar and Heliospheric Observatory (SOHO) spacecraft has been watching recent sunquakes and broadcasting the data back to Earth in the hope of giving scientists new insight into the solar mystery.
The most useful quakes, oscillations called 5-minute oscillations with a frequency of around 3 millihertz, can be thought of as a vibrating bell in the middle of a desert that is constantly brushed randomly by grains of sand. This is similar to how the Earth rings with seismic waves during the aftermath of an earthquake. However there is another factor to take into consideration for sunquakes - what Christoffer Karoff and Hans Kjeldsen from the University of Aarhus, Denmark, pulled out from the SOHO data was very different to the bell in the desert picture.
“The signal we saw was like someone occasionally walking up to the bell and striking it, which told us that there was something missing from our understanding of how the Sun works,” Karoff says. They found that the cause of this sudden striking was solar flares and that increases in solar flares intensified the 5-minute oscillations. Now they have identified the correlation, researchers want to understand how the solar flares induce oscillations. “We are not completely sure how the solar flares excite the global oscillations,” says Karoff.
This new found correlation between solar flares and sunquakes may also provide a way for astronomers to study other stars.
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