Washington, Oct 28 : Astronomers have discovered that the nearby star Epsilon Eridani, which can be considered as our solar system's younger twin, has two rocky asteroid belts, and an outer icy ring, making it a triple-ring system.
The inner asteroid belt is a virtual twin of the belt in our solar system, while the outer asteroid belt holds 20 times more material.
Moreover, the presence of these three rings of material implies that unseen planets confine and shape them.
The star Epsilon Eridani is slightly smaller and cooler than the Sun. It is located about 10.5 light-years from Earth in the constellation Eridanus.
Epsilon Eridani is the ninth closest star to the Sun and is visible to the unaided eye. It is also younger than the Sun, with an approximate age of 850 million years.
Epsilon Eridani and its planetary system show remarkable similarities to our solar system at a comparable age.
"Studying Epsilon Eridani is like having a time machine to look at our solar system when it was young," said Smithsonian astronomer Massimo Marengo. According to Lead author Dana Backman from the SETI Institute, "This system probably looks a lot like ours did when life first took root on Earth."
Our solar system has a rocky asteroid belt between Mars and Jupiter, about 3 astronomical units from the Sun.
In total, it contains about 1/20 the mass of Earth's Moon.
Using NASA's Spitzer Space Telescope, the team of astronomers found an identical asteroid belt orbiting Epsilon Eridani at a similar distance of 3 astronomical units.
They also discovered a second asteroid belt 20 astronomical units from Epsilon Eridani, about where Uranus is located in our solar system.
The second asteroid belt contains about as much mass as Earth's Moon.
A third, icy ring of material seen previously extends about 35 to 100 astronomical units from Epsilon Eridani. A similar icy reservoir in our solar system is called the Kuiper Belt.
However, Epsilon Eridani's outer ring holds about 100 times more material than ours.
When the Sun was 850 million years old, theorists calculate that our Kuiper Belt looked about the same as that of Epsilon Eridani.
Since then, much of the Kuiper Belt material was swept away, some hurled out of the solar system and some sent plunging into the inner planets in an event called the Late Heavy Bombardment.
It is possible that Epsilon Eridani will undergo a similar dramatic clearing in the future.
"Epsilon Eridani looks a lot like the young solar system, so it's conceivable that it will evolve similarly," said Marengo.