Several weeks ago, most of the scientific community was all abuzz about the discovery of an exoplanet not more than 40 light years away that was perhaps the most Earth-like ever discovered. I say most, because there are apparently some in the scientific community who think this planet, Gliese 581g, doesn’t exist at all. HERETICS!
Francesco Pepe, an astronomer who works on HARPS data at the Geneva Observatory, said at the IAU meeting this week that his team could not confirm the existence of Gliese 581g. In e-mail correspondence with Astrobiology Magazine, Pepe said that they could not confirm the existence of planet ‘f’ either.
The Geneva team, led by Michel Mayor, announced in 2009 the discovery of planet ‘e’ in the Gliese 581 solar system. At approximately 1.9 Earth masses, this ‘e’ planet is the lowest mass extrasolar planet yet found, and has a 3.15-day orbital period around the star.
“Since Mayor’s announcement in 2009 of the lowest-mass planet Gliese 581e, 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,” said Pepe.
“From these data, we easily recover the four previously announced planets b, c, d, and e.” However, he said they do not see any evidence for planet ‘g,’ the fifth planet in the system as announced by Vogt and his team. “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,” said Pepe.