A team of global astronomers recently found that the Sun’s core rotates near four times faster than its surface.
European Space Agency and NASA’s Solar and Heliospheric Observatory (SOHO), together, helped the solar scientists find evidence of a type of seismic wave in the Sun. These waves are known as g-modes and are low-frequency waves. These waves revealed that solar core is actually rotating four times faster than its surface.
The solar physicists used helioseismology to study the Sun’s interior structure by tracking the way waves move on the star.
The scientists used over 16 years of data collected by SOHO’s GOLF instrument (Global Oscillations at Low Frequencies). The study was published in the journal Astronomy and Astrophysics.
Why is it important?
The Sun’s core may give a clue of how the Sun was formed. After the Sun formed, the solar wind likely slowed the rotation of the outer part of the sun.
The rotation might also impact sunspots, which also rotate.
The researchers studied surface acoustic waves in the Sun’s atmosphere, some of which penetrate to the Sun’s core, where they interact with gravity waves that have a sloshing motion similar to how water would move in a half-filled tanker truck driving on a curvy mountain road. From those observations, they detected the sloshing motions of the solar core.
By carefully measuring the acoustic waves, the researchers precisely determined the time it takes an acoustic wave to travel from the surface to the centre of the Sun and back again. That travel time turns out to be influenced a slight amount by the sloshing motion of the gravity waves, Ulrich said.
The researchers identified the sloshing motion and made the calculations using data collected by SOHO’s GOLF instrument.
The method was developed by the researchers, led by astronomer Eric Fossat of the Observatoire de la Cote d’Azur in Nice, France.