A team of astronomers reported on Wednesday they had snatched the first glimpse of a quadruple star system in the early stages of formation.
The observations, reported in the journal Nature, help to explain how systems with more than one star -- a phenomenon that is surprisingly common in our galaxy -- are born.
The system was found in a fragmented cloud of gas in a well-known "stellar nursery" located in the constellation of Perseus about 800 light years from Earth, the astronomers said.
It comprises a young star and three gas clusters that, within around 40,000 years, are each likely to flare into small stars around a tenth the mass of the Sun, they predicted.
Rough gravitational interplay between the four siblings mean that one of the stars will get expelled from the system in less than a million years, they forecast.
The observations were made by the Very Large Array, a radio telescope in New Mexico, and the Green Bank Telescope, a steerable telescope in West Virginia.
Stars are born from the condensation of dust clouds, but little is known about the factors that cause multiple births, which occurs in nearly one in two stellar deliveries in the Milky Way, rather than singletons.
"It seems like a simple question," said Stella Offner, an astrophysicist at the University of Massachusetts at Amherst.
"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."