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Recently, scientists have postulated that the most abundant stars in our galaxy, red dwarfs, despite being no more than 20 per cent the mass of the sun, might be able to host habitable planets.

But a new study has warned that any 'Earth-like' worlds we spot in the habitable zone of these stars will be nothing more than an illusion – owing to the intense radiation they receive early in their life.

The study claims that so-called 'mirage Earths' will look like our own planet from afar, but peering deeper into the planet will reveal it to be a barren world with no water, or life, on its surface.

University of Washington researchers have claimed that planets around red dwarfs (illustrated) cannot be habitable. It was thought planets around the dim stars could host water and life. But new research says such Earth-like planets are not possible. This is because the stars are more active early on while the planets form

The research was carried out by astronomy graduate student Rodrigo Luger and assistant professor Rory Barnes at the University of Washington.

They studied red dwarfs, also known as M stars, which make up about 75 per cent of stars in our galaxy.

In their study the researchers found that, early in their life, M dwarfs were much more active. This is the same for most stars, but M dwarfs take longer because they are so much smaller.

This means that once planets have formed, roughly 10 million years after the star's formation, they will be subjected to the full brunt of the star's early activity until it quietens down.

Any water present on the planets would therefore be boiled by this intense heat from the sun.

And in a cruel trick on Earth-based astronomers this water would be split into hydrogen and oxygen atoms. The release of the latter would produce huge atmospheres full of oxygen that, from afar, would make the planet look habitable.

But journeying to the surface of the planet would reveal the reality of a dried up world that lost its water long ago - earning the moniker mirage Earths.

'Because of the oxygen they build up, they could look a lot like Earth from afar - but if you look more closely you'll find that they're really a mirage; there's just no water there,' said Mr Luger.

He added that 'many of the planets in the habitable zones of M dwarfs could have been dried up by this process early on, severely decreasing their chance of actually being habitable.'

The researchers say these atmospheres could be 10 times denser than that of Venus and could 'confound our search for life on exoplanets.' 

The research suggests that red dwarf stars do not quieten down before the planets form and boil water away. This leaves a thick atmosphere of oxygen that looks livable, tricking astronomers into thinking they are habitable. But examining the planet up close would reveal no water on its surface (illustration shown)

M dwarf stars, which include red dwarfs, are the most abundant star in our galaxy, making up three out of every four stars. However they are only about 20 per cent as massive as the sun, and thus have much smaller habitable zones (illustration shown) than other types of star

A few years ago it was thought that such stars, just a fifth as massive as the sun, were too weak to be able to host habitable planets.

But more recently scientists had begun to postulate that they might be able to cling onto tight habitable zones, where temperatures are just right for water to form on a planet.

Considering they are by far the most abundant star in the galaxy, discovering they could have habitable planets in orbit is important in the hunt for Earth-like worlds, and life, beyond the solar system.

It will be a major disappointment then if this new research, which threatens to pour water on that hopeful theory, proves to be true.

'All stars form in the collapse of a giant cloud of interstellar gas, which releases energy in the form of light as it shrinks,' Mr Luger said.

'But because of their lower masses, and therefore lower gravities, M dwarfs take longer to fully collapse - on the order of many hundreds of millions of years.'

He added: 'Planets around these stars can form within 10 million years, so they are around when the stars are still extremely bright.

'And that's not good for habitability, since these planets are going to initially be very hot, with surface temperatures in excess of a thousand degrees. When this happens, your oceans boil and your entire atmosphere becomes steam.'

A few years ago it was thought that red dwarf stars (illustrated), just a fifth as massive as the sun, were too weak to be able to host habitable planets. But more recently scientists had begun to postulate that they might be able to cling onto tight habitable zones, where temperatures are just right for water to form on a planet