Star-quakes can help study content of stars hotter and more massive than the Sun
Researchers suggest that the propagation of sound waves due to the movement of gas inside stars produces oscillations on their surface, and the analysis of these oscillations makes it possible to know the internal structure and age of stars.
This finding has turned out to be also effective in the detailed study of stars more massive than the Sun.
To determine the mass and size of planets found around other stars or to date stellar populations in order to limit the number of cosmological models, among other things, it is essential to know what goes on inside a star.
The only gateway we have to that stellar interior is the study of stellar oscillations, or asteroseismology.
Now, for the first time, a study led by researchers from the Institute of Astrophysics of Andalusia (IAA-CSIC) has shown the validity of this tool for the study of stars that are hotter and more massive than the Sun.
"Thanks to asteroseismology we know precisely the internal structure, mass, radius, rotation and evolution of solar type stars, but we had never been able to apply this tool efficiently to the study of hotter and more massive stars," Juan Carlos Suarez, researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) said.
In some sense, stellar seismology conceives of stars as resonating cavities where the movement of gas generates sound waves. Many of these sound waves tend to fade out, but if they find any mechanism to sustain them, they will reach an equilibrium on the surface of the star and deform it, producing different modes of oscillation (which can be observed as changes in temperature and glow).
To know the mean density of a star allows us not only to determine its mass and radius with precision but also to grasp precisely what model will best yield other essential characteristics of the star, which in turn are indispensable to determine the mass, the radius or the age of extrasolar planets -- planets that orbit around different stars than the Sun.
"Planets orbiting around stars which are more massive than the Sun are being discovered ever more frequently, and these new methods will make it possible to determine their characteristics. This adds value to the PLATO (ESA) mission, which will describe planetary systems and contribute precious information to understand their origin and evolution, which in turn is essential for the search of extraterrestrial life," Suarez, member of the PLATO mission board said.
These results were reached using a tool named TOUCAN, an asteroseismology model management tool developed by researchers from the Institute of Astrophysics of Andalusia and the Spanish Virtual Observatory (CAB-INTA-CSIC).
(Posted on 02-04-2014)