LONDON-Two planets in a solar system that looks similar to our own could have the right conditions for life to flourish.
The planets are located in the Trappist-1, a system with seven worlds orbiting a dwarf star 39 light years away.
Since Nasa first announced its discovery of Trappist-1, many have argued life could exist there.
Now, scientists believe Earth-like planets d and e are likely to have water and enough heat to harbour life.
Scientists now hope they can use new equipment like the upcoming James Webb Telescope to be able to study the planets in more detail.
No other star system known contains such a large number of Earth-sized and probably rocky planets.
The Trappist-1 planets are referred to by letter, planets b through h, in order of their distance from the star.
A study by the Planetary Science Institute calculated the balance between tidal heating and heat transport by convection in the mantles of each planet.
‘Assuming the planets are composed of non-compressible iron, rock, and water, we determine possible interior structures for each planet’, researchers led by Dr Amy Barr, wrote in the paper set to be published in the journal Astronomy & Astrophysics. ‘With the exception of Trappis-1c, all seven of the planets have densities low enough to indicate the presence of significant water in some form’, researchers wrote.
Their study revealed that planets d and e are the most likely to be habitable.
This is due to their moderate surface temperatures, modest amounts of tidal heating, and because their heat fluxes are low enough to avoid entering a runaway greenhouse state.
Researchers found that planets b and c likely have partially molten rock mantles, writes the Guardian.
The paper also shows that planet c likely has a solid rock surface, and could have eruptions of silicate magma on its surface driven by tidal heating, similar to Jupiter’s moon Io. Planet d has a temperature of around 15C (59F) while planet b is colder and would be a similar temperature to Antarctica. A global water ocean likely covers planet d.
‘Because their orbits are eccentric –not quite circular – these planets could experience tidal heating just like the moons of Jupiter and Saturn,’ said Dr Barr from the Planetary Science Institute.
Because the Trappist-1 star is very old and dim, the surfaces of the planets have relatively cool temperatures by planetary standards.
They range from 400 degrees Kelvin (260 degrees Fahrenheit), which is cooler than Venus, to 167 degrees Kelvin (-159 degrees Fahrenheit), which is colder than Earth’s poles.
The planets orbit very close to the star, with orbital periods of a few days.
At 39 light years away the Trappist-1 system is relatively close to Earth considering the grand scale of the Milky Way galaxy they inhabit, which measures 100,000 light years across.
But researchers suggest that the Trappist-1 system is too far to ever be reached by humans, at least with current technology. ‘The chances for humans reaching the system at the moment are not very good,’ study co-author Dr Amaury Triaud, an astronomer at Cambridge University, told MailOnline.
Our technology is really far from even sending a robotic probe, and the feasibility of humans surviving long term space travel is completely unknown.
‘Unless we find a new physical process to harness energy I don’t see us colonising these planets in our lifetime, but then maybe someone will be inspired by the system and discover the means to go there, who knows!’
Fellow astronomer Professor Ignas Snellen of the Netherlands’s Leiden University, not involved in the study, agrees.
‘Although the star is relatively nearby that is still very very far for humans to travel,’ he told MailOnline.
‘It would take hundreds of thousands of years to get there, maybe more.’