An international team1, led by the Institute of Astrophysics and Space Sciences (IA2) recently detected solar siblings. Located about 184 light-years away, it's called HD 186302, and it's almost certainly at least a lost brother of our birth star.
Solar brothers are a large number of stars that formed in a group indistinguishable from the Sun, about 4.6 billion years ago. Over time, the stars of the group dispersed and spread throughout our galaxy, making it extremely difficult to discover them.
Vardan Adibekyan (IA & University of Porto) explains the importance of finding these stars: "Since there is not much information about the Sun's past, studying these stars can help us understand where in the Galaxy and under what conditions the Sun has formed. "
"With the collaboration of Patrick de Laverny and Alejandra Recio-Blanco from the Côte d'Azur Observatory, we obtained a sample of 230,000 AMBRE spectra. AMBRE is a galactic archeology project established by ESO and the Côte d'Azur Observatory to determine the stellar atmospheric parameters for the filmed spectra of the ESO FEROS, HARPS4, UVES and GIRAFFE spectrographs. "
Solar brothers can also be a major contender for the quest for life, since there is a possibility that life has been transported between planets around solar-powered stars. The interchange of life between exoplanetary structures is called interstellar litopanspermia.
Adibekyan is cautiously enthusiastic about this possibility: "Some theoretical calculations show that there is an undeniable probability of life spreading from Earth to other planets or exoplanetary systems during the period of heavy late bombardment. If we are lucky, and our brother candidate has a planet, and the planet is rocky, in the habitable zone, and finally, if this planet is "contaminated" by the earth's vital seeds, then we will have what we could dream of – an Earth 2.0, orbiting a Sun 2.0. "
The AI team plans to start a campaign to search for planets around that star using the HARPS and ESPRESSO spectrographs. Finding and characterizing planetary systems around siblings could return very important information about the outcome of planet formation in a common environment.
The article was published in the journal Astronomy & Astrophysics.