Nearly half of all Sun-sized stars observed so far are binary.
This means that one Sun-sized star and another star are orbiting a common center of mass, while exoplanets orbit the two giants.
A new study from researchers at the University of Copenhagen suggests that planets orbiting binary stars form very different to Earth and other planets orbiting single stars, a press statement reveals. It provides a new avenue of research in the search for extraterrestrial life.
Investigating binary star systems for alien life
The research was conducted on observations of a binary star made by the ALMA (Atacama Large Millimeter/submillimeter Array) telescopes in Chile. The binary star system, called NGC 1333-IRAS2A, is located 1,000 lightyears from Earth and the University of Copenhagen team found that the system is surrounded by a disc consisting of gas and dust.
They developed computer simulations based on these observations to map out how planets may have evolved around this type of system, and they hope that future observations will be able to corroborate their findings.
"[It] is exciting since the search for extraterrestrial life will be equipped with several new, extremely powerful instruments within the coming years. This enhances the significance of understanding how planets are formed around different types of stars," explained Professor Jes Kristian Jørgensen, Niels Bohr Institute, University of Copenhagen, the head of the project.
The simulations showed that the movement of gas and dust likely doesn't follow a continuous pattern. For long periods of time, the star could become much brighter, suggesting the movement of dust is stronger.
This is likely down to the fact that the binary stars' joint gravity affects the gas and dust disc differently depending on their proximity to one another. When it's stronger, it causes a massive amount of material to fall towards the stars.
"The falling material will trigger significant heating. The heat will make the star much brighter than usual," said Postdoc Rajika L. Kuruwita, Niels Bohr Institute, second author on the study. "These bursts will tear the gas and dust disc apart. While the disc will build up again, the bursts may still influence the structure of the later planetary system."
Comets could bring life to planets orbiting binary stars
No planets have formed around the binary star system NGC 1333-IRAS2A, though the University of Copenhagen researchers hope to study more ALMA observations of similar star systems. They also explained that they will focus on comets, as these likely play an important role the evolution of life on planets.
"The wavelengths covered by ALMA allow us to see quite complex organic molecules, so molecules with 9-12 atoms and containing carbon," Kristian Jørgensen explained. "Such molecules can be building blocks for more complex molecules which are key to life as we know it. For example, amino acids which have been fund in comets."
The ALMA network is made up of 66 telescopes that operate in coordination, allowing for a much higher resolution than would be possible using a single telescope. The James Webb Space Telescope will soon also join the search for extraterrestrial life, and it will be joined by the ELT (European Large Telescope) and the SKA (Square Kilometer Array), both of which are scheduled to begin observing the cosmos in 2027.