One of the closest stars to the sun may be circled by a planet just like Earth, scientists say. And the replica world could have substantial amounts of water on its surface – vital for life like our own to develop.
The distant world was not detected with a telescope. Instead astronomers used a computer to discover whether or not it might exist. They looked at four stars in our own cosmic back yard which are already known to have at least two giant planets in orbit around them.
They then produced computer simulations to model conditions in those alien solar systems. Their tests showed that one star – Rho in the constellation of Cancer – was able to build a planet similar to Earth in the so-called habitable zone where it could sustain life.
The star, also known as 55 Cancri, is virtually on our doorstep at a distance of only 40 light years. Just visible to the naked-eye, it is a double star with one star resembling our own sun and a red dwarf companion. It is already known to have four giant planets similar in size to Jupiter or Neptune.
Another star studied was likely to have an asteroid belt of tiny worlds smaller than Mars, the study found. The two other stars tested were incapable of producing terrestrial-type planets.
For each of the star systems, the researchers placed small planet “embryos” into the simulation. They then jumped 100 million years to see whether they were able to gather material and build up to form planets like Earth. Nasa helped fund the research by scientists from universities in Arizona, Colorado and Washington and published in the Astrophysical Journal.
Researcher Dr Rory Barnes said: “It’s exciting that our models show a habitable planet, a planet with mass, temperature and water content similar to Earth’s, could have formed in one of the first extrasolar multi-planet systems detected.”
The scientists found that a star called HD 38529 could have the asteroid belt. But no planets formed in models of the other stars, HD 37124 and HD 74156. Image by Nasa.