Solar systems like ours may be very rare

How common is our solar system? Less common than one might think. A significant fraction of the planetary systems around Sun-like stars have had a very dynamic past, culminating in the fall of the planets into the central star. A new study involving Monash University astrophysicists sheds light on the scarcity of our Solar System, which has preserved its planets and kept them on near-circular orbits, a disposition conducive to the prosperity of life on Earth.

The research, recently published in Nature Astronomy and led by Dr. Lorenzo Spina at the National Institute of Astrophysics based in Italy, broadens our knowledge on the possible evolutionary paths of planetary systems, according to study co-author Parth Sharma. Honors student at Monash University School of Physics and Astronomy.

“Regardless of the technology at our disposal, with millions of Sun-like stars nearby, the search for Earth-like planets will always resemble the proverbial 'needle in a haystack, '”Parth said. "However, our results open up the future possibility of using chemical abundances to better identify stars that could host analogs of the Solar System," he added. "These results represent a significant breakthrough in stellar astrophysics and exploration of exoplanets. The research refines the parameters for the future investigation of potential planetary swallowing events, probes the origins of chemically strange stars and tells us a lot about the evolution of solar systems and planets, such as ours ".



The stellar members of binary systems are formed from the same material, so they should be chemically identical. However, recent high-precision studies have revealed chemical differences between the two members of binary pairs made up of Sun-like stars. The very existence of these chemically inhomogeneous binaries represents one of the most contradictory examples in stellar astrophysics and a source of tension between theory. and observations.

"It is not yet clear whether the abundance variations are the result of chemical inhomogeneities in the protostellar gas clouds, or whether they are due to planet-engulfing events that occur after the star has formed, ”Parth said. The research team undertook a statistical study of 107 binary systems composed of Sun-like stars to provide - for the first time - unambiguous evidence in favor of the planet-engulfing scenario, establishing that the planet-engulfing events occurred in stars similar to our Sun with a probability between 20% and 35%. "This implies that a significant fraction of planetary systems undergo very dynamic evolutionary paths that can critically and disastrously change their architectures, unlike our Solar System which has retained its planets in near-circular orbits," Parth concluded.