SIGNS of an alien planet that’s about the same size as Earth have been picked by up a Nasa telescope.
Scientists say it might even be within its host star’s “habitable zone”, but there’s a big problem: it’s probably a miserable ice-world.
This artist’s concept of possible exoplanet HD 137010 b might be a frozen EarthCredit: NASA/JPL-Caltech/Keith Miller (Caltech/IPAC)
In fact, its surface temperature might be as low as -68C – hardly the space getaway we’ve been dreaming of.
The possible “ice-cold Earth” is named HD 137010 b, and it’s believed to be a rocky planet.
It’s believed to be orbiting a Sun-like star around 146 lightyears away, according to researchers at the University of Southern Queensland and the Max Planck Institute for Astronomy.
And it’s only slightly more massive than our home world, which puts it in the Earth-like category.
It was picked up as part of data from Nasa’s Kepler Space Telescope, which retired back in 2018.
This is classified as an exoplanet, which means it’s a planet that orbits a star outside of our own Solar System.
Interestingly, the planet’s orbital period – the time it takes to whizz around its star – is believed to be about the same as Earth: one year.
But if you’re hoping to retire on this Earth-like world one day, don’t start planning your trip just yet.
“Now the bad news. The amount of heat and light such a planet would receive from its star is less than a third of what Earth receives from the Sun,” said Nasa’s Pat Brennan.
“Although of a stellar type similar to our Sun, the star, HD 137010, is cooler and dimmer.
Nasa’s Kepler space telescope – which captured the data for this planet – was launched on 2009 and mapped hundreds of thousands of stars before retiring in 2018Credit: NASA, ESA, CSA, and STScI
“That could mean a planetary surface temperature no higher than minus 90 degrees Fahrenheit (minus 68 degrees Celsius).
“By comparison, the average surface temperature on Mars runs about minus 85 degrees Fahrenheit (minus 65 degrees Celsius).”
But what really gets scientists excited about this kind of planet is its potential for being in the “habitable zone”.
That’s a zone of distance to a star that could allow for liquid water to form on the planet’s surface under an appropriate atmosphere.
Astronomers have modelled the star’s possible atmosphere, and they think it has a 40% chance of falling inside the conservative habitable zone of the star.
And there’s a 51% chance of it falling into a slightly larger “optimistic” habitable zone.
If it does fall into the habitable zone then it could end up being a “temperate of even a watery world”, Nasa writes, explaining the study.
The other bad news is that this planet is still technically only a “candidate” rather than being “confirmed”.
There’s a chance that the planet could be within its star’s habitable zoneCredit: NASA/JPL-Caltech/Keith Miller (Caltech/IPAC)
One of the main ways scientists find exoplanets is by looking for “transits”.
This is when a planet passes across the face of its star during orbit, creating a “miniature eclipse”.
And this dip in brightness allows scientists to pick up that a large object is passing in front of the star.
Normally you’d want repeated passings to work out how long the orbital period is.
The Kepler space telescope ‘revealed our night sky to be filled with billions of hidden planets’, Nasa saidCredit: NASA/Ames Research Center/W. Stenzel/D. Rutter
But scientists only had Kepler data on a single transit, so they had to track the time it took for the planet’s shadow to move across the star’s face (about 10 hours) and compare it to orbital models of the system.
However, astronomers will now need to see repeat transits for this planet to confirm that it’s real.
The problem is that because the planet has a large orbital distance – like Earth – you have to wait a long time for another transit to occur.
This research was published in The Astrophysical Journal Letters.