“Gliese 581g,” the planet orbiting the star Gliese 581 said to have Earth-like habitability, may not actually exist, according to a report in Astrobiology Magazine on Tuesday.
The planet is at just the right size—around three times the size of the earth—and at just the right temperature to harbor life as we know it. The solar system is located in the constellation Libra, 20 light-years away from our planet.
Before, scientists had found four planets circling the star, but none were located in the habitable zone, which is necessary for a planet to have liquid water.
On Monday, scientists at the International Astronomical Union meeting raised concerns that the new, fifth planet may not reside in Gliese 581‘s habitable zone.
Francesco Pepe, who works with the Geneva Observatory and used the HARPS instrument on the La Silla telescope at the European Southern Observatory in Chile, said he and his team could not find the planet or confirm its existence.After the “announcement in 2009 of the lowest-mass planet Gliese 581 e, we have gathered about 60 additional data points with the HARPS instrument for a total of 180 data points spanning 6.5 years of observations,” Pepe told Astrobiology Magazine. “From these data, we easily recover the 4 previously announced planets b, c, d, and e.”
He added that his team could not find any evidence for a “g” planet.
“The reason for that is that, despite the extreme accuracy of the instrument and the many data points, the signal amplitude of this potential fifth planet is very low and basically at the level of the measurement noise,” Pepe continued.
As a result, Pepe said he could not confirm the existence of the planet. However he did not deny its existence.