A Canadian study of a distant star failed to confirm the existence of the orbiting "super Earth" hailed by European astronomers two months ago.
But University of British Columbia astronomer Jaymie Matthews said the observations of the light coming from the red dwarf star Gliese 581 suggest the star is stable enough to support life on an orbiting planet.
Matthews presented his findings on Saturday at the Canadian Astronomical Society's annual meeting, held this year at the Royal Military College in Kingston, Ont.
Gliese 581 is 20.5 light years — or 194 trillion kilometres — away from Earth, but attracted worldwide attention in April when scientists with the European Southern Observatory announced they had detected a number of planets around it, including one that had a diameter about 50 per cent larger than Earth's.
The planets were discovered by studying the variations in the velocity of the star as a result of the gravitational pull from unseen planets. Measuring these velocity variations allowed the scientists to deduce the orbits, distance and minimum mass of the planets.
Using the Canadian Space Agency's suitcase-sized device, the Microvariability and Oscillations of Stars (MOST) telescope, Matthews went looking for more direct evidence.
He and his team of researchers looked for changes in the light coming from the star, hoping to catch a glimpse of dips in the light when a planet would pass directly in front of the star to create a mini-eclipse. But after six weeks of looking, the telescope failed to notice any significant occurrences.
The lack of confirmation doesn't mean the planets are not there, he said, but simply that the MOST telescope was unable to detect them because the planet transit of the star didn't line up with our view of the star.
Matthews said while the odds of the planet transiting in front of our view of the star were about one in 50, it was a gamble worth taking.
"It's like playing the lottery, but we wanted to play the game because the jackpot is huge," he told CBC News online.
The super planet has attracted attention because its distance from the red dwarf star suggests it might be able to hold liquid water, one of the key ingredients needed to support lifeon Earth.
Stability a good sign
Matthews said the stability of the star — as evidenced by the light coming from it — is another good sign.
"The climate on the planet should not be a wild roller-coaster ride that would make it difficult for life to get a foothold," Matthews said.
"It also suggests the star is quite old and settled in its ways, and that the planets around it have probably been around for billions of years."
It took about 3.5 billion years for life on Earth to reach the level of complexity of humans, Matthews said.
"So if Gliese 581 has been around for at least that long, it's more encouraging for the prospects of complex life on any planet around it," he said.
The star's stability was also good news for astronomers because it meant the wobbling the ESO observed was not the result of turbulence inherent in the star itself.
The MOST results are the first of what are expected to be many observations of the Gleise system in search of direct evidence of the planet. NASA's Terrestrial Planet Finder is expected to be able to see at far greater distances when it goes into operation, though the project currently has no launch date.