Stars are not perfect spheres , we already know that. For example, when rotating, with the phenomenon of rotation, they become flatter due to centrifugal force. The faster the rotation, the flatter a star becomes.
Now, a team of researchers from the Max Planck Institute for Solar System Research and the University of Göttingen (Germany) has managed to measure the oscillation of a very particular star with unprecedented precision. This star, which is 5,000 light years from Earth, is more than twice the size of the Sun and rotates three times slower. As if this were not enough, it is the roundest natural object in the universe so far.
How did they find out?
The oscillations of the stars are studied by asteroseismology, since the periodic expansions and contractions of the star can be detected in the fluctuations of the star’s brightness.
Applying this technique to the Kepler star 11145123 observed through NASA’s Kepler Space Telescope, the experts found that the difference between the star’s polar and equatorial radii is only 3 kilometers with an accuracy of 1 kilometer – a surprisingly small number. Compared to the star’s mean radius of 1.5 million kilometers – which means the gas sphere is astonishingly round.
” This makes Kepler 11145123 the roundest natural object ever measured, even rounder than the Sun,” explains Laurent Gizon, leader of the study.
The funny thing is that this star is even less flattened than expected , so scientists believe that the presence of a magnetic field at low latitudes could be responsible for the star looking more spherical than it should be.
“We intend to apply this method to other stars observed by Kepler and the upcoming TESS and PLATO space missions. It will be particularly interesting to see how faster rotation and a stronger magnetic field can change the shape of a star . The theoretical field of astrophysics has become observational ”, comments Gizon.
The discovery has been published in the journal Science Advances.
