London  - Two Earth-like planets could be orbiting a star in Alpha Centauri, our closest solar system.

The mystery worlds are thought to be much too hot to support life, with surface temperatures of around 1,500°C. But astronomers say they could be part of a more extensive solar system containing watery worlds like our own 4.3 light years away.

The first planet, dubbed Alpha Centauri Bb, was discovered in 2012, but quickly dismissed by scientists who believed it had been a false alarm.

Now a team of astronomers, led by Cambridge University, has taken a second look at the evidence. ‘If you ask anyone working in exoplanets, they would all have a different opinion about the existence of Alpha Centauri Bb,’ Brice-Oliver Demory of the University of Cambridge told the New Scientist. The original method of looking for the planet was based on measuring tiny wobbles in the motion of Alpha Centauri B caused by a gravitational tug of war with the orbiting planet.

The latest study has combined that data with Hubble’s technique of looking for a dip in the light from Alpha Centauri B caused by the planet passing in from of the star. The team observed Alpha Centauri B in 2013 and 2014, for a total of 40 hours.

The 2013 data showed signs of a transit, but they were longer than expected. But the signal disappeared completely in the 2014 data set. According to the New Scientist, the researchers say that doesn’t mean the planet isn’t there, just that it is difficult to be seen from Earth. They believe the signal in the 2013 data may be another Earth-sized planet in that solar system with a year lasting around 20.4 days. This discovery suggests there is a chance of other planets in the same solar system which may have conditions in which life could thrive.

This isn’t the first time scientists have attempted to prove the existence of a planet that has been dismissed as ‘noise’.

Last month, astronomers said mysterious signals - previously dismissed as stellar bursts - are coming from an Earth-like planet. The Gliese 581d planet has conditions that could support life, and is likely to be a rocky world, twice the size of Earth.

Signals from the planet were initially discovered in 2010, but last year thought to be noise from distant stars. Pennsylvania State University researchers said Gliese 581d - and its companion Gliese 581g - were simply a trick of the light caused by magnetic bursts from a local star 22 light-years away. The new British research, however, argues the method used by the Pennsylvania team was only suitable for large planets, and that it could miss small ones like GJ 581d.