There is a relationship between the growth of star 'embryos' and the disc of matter that has surrounded them since the very beginning: this is demonstrated by the study of the 26 brightest and closest protostars to us, conducted by an international group led by Eleonora Fiorellino dell 'National Institute of Astrophysics (Inaf).
The results, published in The Astrophysical Journal Letters, will allow us to identify the initial conditions that give rise to the formation of planets around low-mass stars such as our Sun.
The study investigates the accretion process by which a part of the material of the circumstellar disk, following the magnetic field lines of the star in formation, arrives on the star itself, increasing its mass.
A similar analysis had already been carried out for slightly more evolved objects: the so-called main pre-sequence stars, or the stage that precedes the main sequence, a fundamental phase of the evolution of a star characterized by the fusion of hydrogen in the nucleus.
But no one had focused on the protostars, that is, the stage preceding the pre-sequence stars.
The protostars are not visible in the optical band and it is much more complicated to study them since observations in the infrared band are required.
Thanks to new instruments (including Kmos mounted on the Very Large Telescope of the European Southern Observatory in Chile) and the use of new analysis techniques, Fiorellino studied the 26 brightest protostars within about 1,600 light years from us, calculating their growth rates.
Furthermore, observations obtained with the Alma telescope allowed the researchers to calculate the mass of the disks that surround them.
"This work - comments Fiorellino of the INAF of Naples - shows an evident evolutionary trend between bright protostars and pre-sequence stars, suggesting that we go and study even younger and less bright protostars with more powerful instruments from Earth or with the James telescope. Webb in space.
It also shows that models that are successful in explaining the pre-sequence steps fail when applied to protostars. "