Astronomers at the Atacama Large Millimeter/submillimeter Array (ALMA) observatory in Chile have found a young solar system, much like our own, forming around an alien star. The star around which this system is found, DM Tau, looks much like our Sun likely did in its early days.
Two rings of gas and dust are coalescing around the star at distances roughly equal to that of the asteroid belt and Neptune in our own solar system. This young system is located approximately 470 light years away from our own stellar companion.
“Previous observations inferred two different models for the disk around DM Tau. Some studies suggested the radius of the ring is about where the Solar System’s asteroid belt would be. Other observations put the size out where Neptune would be. Our ALMA observations provided a clear answer: both are right. DM Tau has two rings, one at each location,” said Tomoyuki Kudo, an astronomer at the National Astronomical Observatory of Japan (NAOJ).
Within the outer ring of DM Tau lies a bright patch, which could be a site where a large planet, like Uranus or Neptune, might be forming. Even in our modern solar system, rings of dust and gas follow the three innermost planets in their journeys around the Sun.
Our own solar system formed 4.6 billion years ago from a similar cloud of gas as that seen around DM Tau. By studying young solar systems around other stars, astronomers hope to learn more about the formation of our own family of planets.
“We are also interested in seeing the details in the inner region of the disk, because the Earth formed in such an area around the young Sun. The distribution of dust in the inner ring around DM Tau will provide crucial information to understand the origin of planets like Earth,” Jun Hashimoto, a researcher at the Astrobiology Center in Japan explained.
The asteroid belt in our own solar system is thought to have played a major role in the delivery of water to the Earth, billions of years ago. This system of asteroids sits at a distance known as the water snowline, where water can be found, frozen into ice. As the massive planet Jupiter altered the orbits of the asteroids, some of these interactions would send icy bodies to the young Earth.
“The water snowline in the DM Tau system, with a host star less luminous than the proto-Sun, should be located closer to its host star than that in the solar system… Should terrestrial planets be forming inside its snowline, water delivery from the inner ring onto the inner planets might be plausible,” researchers wrote in The Astrophysical Journal.
The mass of DM Tau, seen in the constellation of Taurus the Bull, is roughly half that of our own Sun, and the star is believed to be between three and five million years old.
The ALMA observatory is designed to study weak radio waves emitted by gas and dust surrounding distant stars. The system has captured energy from objects 13 billion light years from Earth, created when the first galaxies in the Universe came into being.