Can we live on distant planets? NYU Abu Dhabi study determines habitability

Scientists have been trying to find signs of life on exoplanets – planets outside our solar system – for nearly two decades

An artist's impression of an exoplanet's atmosphere evaporating into space. Courtesy: Nasa

Researchers in Abu Dhabi are studying how a planet's relationship with its host star can affect its ability to support life.

A new study by NYU Abu Dhabi found that emissions from host stars can strip away the atmosphere of planets orbiting them. Scientists believe that planets with no atmosphere are uninhabitable.

Results of the study were published in the Monthly Notices of Royal Astronomical Society: Letters journal this month and led by research scientist Dr Dimitra Atri with involvement from graduate student Shane Carberry Mogan.

After looking at 493 host stars outside our solar system, it was found that extreme ultraviolet radiation and stellar flares from some categories of host stars can destroy the upper atmosphere of planets orbiting them.

"We have identified exoplanets in the M0 to M4 [host stars] category are least likely to be habitable, because their atmospheres will be completely eroded by extreme ultraviolet radiation," Dr Atri told The National.

So far, scientists have discovered 4,000 planets around more than 3,000 host stars, none of which have shown habitable conditions similar to Earth's.

To find distant planets that can support life, researchers look at planets in habitable zones known as the Goldilocks Zone. This is a zone where planets are not too close or too far from their host star, allowing it to sustain water.

For example, Earth is far enough from its host star, the Sun, to avoid radiation, yet close enough to stay warm.

“Given the close proximity of exoplanets to host stars, it is vital to understand how space weather events tied to those stars can affect the habitability of the exoplanet,” Dr Atri said.

His study showed that lighter stars that get less excessive radiation have more chances of having habitable planets orbiting them.

The findings could help scientists take a host star’s radiation levels into account when trying to determine an exoplanet’s ability to support life.

Dr Atri used data from Nasa’s Transiting Exoplanet Survey Satellite observatory for his study.

“The next research step would be to expand our data set to analyse stellar flares from a larger variety of stars to see the long-term effects of stellar activity, and to identify more potentially habitable exoplanets,” he said.

Dr Atri also hopes to use data from UAE’s Emirates Mars Mission to analyse how the Red Planet lost most of its atmosphere.

Scientists believe the planet once supported ancient life.

The wonders of outer space – in pictures 

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  Helix Nebula is a phase when a star like the Sun runs out of fuel, it expands and its outer layers puff off, and then the core of the star shrinks. All photos: Nasa

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  This Cartwheel Galaxy resembles a bull's eye, which is appropriate because its appearance is partly due to a smaller galaxy that passed through the middle of this object.

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  On February 24, 1987, observers in the southern hemisphere saw a new object in a nearby galaxy called the Large Magellanic Cloud. This was one of the brightest supernova explosions in centuries and soon became known as Supernova 1987A.

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  Messier 82, or M82, is a galaxy that is oriented edge-on to Earth. This gives astronomers an interesting view of what happens as this galaxy undergoes bursts of star formations.

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  Galaxy clusters are the largest objects in the universe held together by gravity. They contain enormous amounts of superheated gas, with temperatures of tens of millions of degrees, which glow brightly in X-rays and can be observed across millions of light years between galaxies.

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  What will be the next star in our Milky Way galaxy to explode as a supernova? Astronomers aren't certain, but one candidate is in Eta Carinae, a volatile system containing two massive stars that closely orbit each other.