Observations of a young binary star system have led astronomers to come up with new ideas about how planets could form. In a system with two or more stars, planetary disks move cyclically through the combined effects of stars, and these dramatic changes are likely to influence the formation of the worlds around these stars. Given that almost half of all stars the size of the Sun are in pairs, understanding these systems is very important.
The starting point of the work, published in the journal Nature, is the observations of the binary star system NGC 1333-IRAS2A. The two stars are surrounded by a disk of gas and dust. Researchers from Denmark, Taiwan, and the United States used simulations to study both the past and future of this system.
The computer model showed that, from the snapshot in time that are the recent observations, the movement in the disk does not follow a continuous pattern. It seems that for short periods of time, lasting a few decades every few thousand years, binary stars become up to 100 times brighter before returning to their baseline.
“The falling material will cause significant warming. The heat will make the star much brighter than usual,” co-author Rajika L. Kuruwita of the Niels Bohr Institute said in a statement. “These explosions will break the gas and dust disk. Although the disk will accumulate again, the explosions can still influence the structure of the later planetary system.”
The observations were made with the Atacama Large Millimeter / Submillimeter Array, which has the ability to see the emissions of interesting chemicals that form around the stars. Although the binary system does not yet have planets around it, the observatory can study what substances are currently there and the team can speculate on what might form in the future.
“The warming caused by the explosions will cause the grains of dust and the surrounding ice to evaporate. This may alter the chemical composition of the material from which the planets are formed,” added Professor Jes Kristian Jørgensen, of the ‘Niels Bohr Institute of the University of Copenhagen, which directs the project.
The new observatories, from the JWST to the Square Kilometer Array and the Extremely Large Telescope, will further investigate systems like this and provide new insights into whether and how planets around binary stars could come to life.
“The result is exciting, as the search for extraterrestrial life will be equipped with several new and extremely powerful instruments in the coming years,” said Professor Jørgensen. “This enhances the importance of understanding how planets form around different types of stars. These results may identify places that would be especially interesting for investigating the existence of life.”