An international team of astronomers have caught the first glimpse of a multiple-star system during its earliest stage of formation.
“It seems like a simple question,” says University of Massachusetts Amherst astrophysicist Stella Offner.
“Why is our sun a single star while the nearest star to us, Alpha Centauri, happens to be a triple system? There are competing models for how multiple star systems are born, but now we know a little more than we did before.”
Observing how multiple star systems form helps astronomers understand other cosmic phenomena like star and planet formation. Jamie Pineda, one of the authors of the study, says the number of stars in a multiple-star system is determined during the beginning stages of the system’s formation. But, the actual formation itself is often obscured by thick clouds of dust and gas.
The team of astronomers found this star system in the ‘stellar nursery’ region of the constellation Perseus. The Very Large Array (VLA) and the Green Bank Telescope (GBT) gave astronomers high-resolution observations of the star system.
Thanks to the two observatories, astronomers can see three gas condensations and one newly born star. Astronomers believe these condensations will turn into stars over the next 40,000 years. It’s hard for us to wrap our heads around that much time, but for the universe it’s pretty short.
Once the stars are finished forming, the system will be a quadruple star system. The team of astronomers believes that it will eventually become a triple star system. The gravitational interactions between the four stars is expected to lead to one of the stars being tossed out of the system.
Offner says the observations they have made help them better understand why some systems have just a single star (like our own), while others have two or more. Multiple star systems are widespread throughout our galaxy. Half of all stars are located in multiple star systems. Even the nearest star to our sun, Alpha Centauri, is a binary star system.
Offner touches on what their discovery means for our own sun’s formation. “In terms of what this means for the formation of our sun,” Offner says. “It suggests that its early conditions did not look like this forming system. Instead, the sun likely formed from something that was more spherical than filamentary. The distribution of the planets in our solar system also suggests that our sun was never part of a multiple system like this one.”
You can check out the full study here.
Image credit: UMass Amherst. Image is a numerical simulation modeling a triple star system.