Astronomers have reported discovering a potentially habitable super-earth some 31 lights years away from us.
The exoplanet, called GJ 357 d, is approximately six times larger than Earth and circles a dwarf star GJ 357, much smaller than our own, every 55.7 days.
But what’s interesting is the fact that the group of astronomers who made the discovery have revealed that the alien planet “provide Earth-like conditions.”
“With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth, and we could pick out signs of life with telescopes that will soon be online,” Lisa Kaltenegger, the director of the Carl Sagan Institute at Cornell and associate professor in astronomy, said in a statement.
“If GJ 357 d were to show signs of life, it would be at the top of everyone’s travel list – and we could answer a 1,000-year-old question on whether we are alone in the cosmos.”
However, without an atmosphere around the planet, the alien world could be home to an equilibrium temperature of around 64 degrees below zero, according to NASA, which would make it “more glacial than habitable.”
The new exoplanet, one of more than 4,00 confirmed alien worlds, was discovered thanks to NASA’s new planet-hunting Transiting Exoplanet Survey Satellite (TESS).
The discovery of the potentially habitable exoplanet came after astronomers first discovered an extremely hot planet orbiting the star GJ 357, located in the constellation Hydra.
The world, a piping hot exoplanet was discovered in February, as the cameras installed on TESS observed the star dimm slightly every 3.9 days. This was a telltale sign that there was a planet passing in front of the star, causing the star’s light to slightly decrease.
“In a way, these planets were hiding in measurements made at numerous observatories over many years,” said Rafael Luque, a doctoral student at the Institute of Astrophysics of the Canary Islands (IAC) on Tenerife who led the discovery team. “It took TESS to point us to an interesting star where we could uncover them.”
The initial signs TESS observed belonged to a planet called GJ 357 b, an alien world around 22% larger than Earth. It orbits 11 times closer to its star than Mercury does our Sun, according to NASA. This means it has an equilibrium temperature of around 490 degrees Fahrenheit (254 degrees Celsius).
“We describe GJ 357 b as a ‘hot Earth,’” revealed co-author Enric Pallé, an astrophysicist at the IAC and Luque’s doctoral supervisor.
“Although it cannot host life, it is noteworthy as the third-nearest transiting exoplanet known to date and one of the best rocky planets we have for measuring the composition of any atmosphere it may possess.”
And while astronomers were working on the data to confirm the existence of GJ 357 b, they came across two additional exoplanets.
The farthest planet from the star, GJ 357 d was the most interesting.
“GJ 357 d is located within the outer edge of its star’s habitable zone, where it receives about the same amount of stellar energy from its star as Mars does from the Sun,” explained Diana Kossakowski at the Max Planck Institute for Astronomy in Heidelberg, Germany.
“If the planet has a dense atmosphere, which will take future studies to determine, it could trap enough heat to warm the planet and allow liquid water on its surface.”
The newly found, potentially habitable exoplanet is believed to weight around 6.1 times the mass of Earth, orbiting its star at a range of about 20% of Earth’s distance from the Sun.
A paper detailing the discovery was published in the journal Astronomy & Astrophysics and is available here.