We’d all like to know more about Gliese 581 c, the most talked about exoplanet of them all because of the possibility — however controversial — that it may be habitable. One way to learn more would be to observe a transit, which is what the Canadian space telescope called MOST is now attempting to do. The odds are roughly one in thirty, according to MOST principal investigator Jaymie Mark Matthews, but even the few observations ahead for MOST will tell us more about the star in question.
Matthews’ thoughts are reported in an article in the British Columbian alternative daily The Tyee, along with a nice backgrounder on the planet by writer Monte Paulsen. Evidently the Swiss team behind the Gliese 581 c announcement, which includes Michel Mayor and Didier Queloz (the first to identify an exoplanet, in 1995), had contacted the MOST controllers at the University of British Columbia before going public with their latest work. They hoped a transit could verify the existence of the new planet and sharpen up our knowledge of its parameters.
From the story:
“We had our first chance earlier this week,” Matthews told The Tyee. “We’ll have another intense stakeout in less than two weeks.”
If MOST does catch a transit, astronomers will be able to combine MOST’s data on the planet’s size and speed with HARP’s observations of mass. “We would be the first to measure the density of an Earth-like planet. No one’s ever been able to do that,” Matthews said. “We would be able to tell whether it was an ocean, or rocky.”
But in the absence of a transit, MOST can still be helpful in looking at how active Gliese 581 actually is. The mission — Microvariability and Oscillations of STars — is uniquely qualified for that project, being designed to conduct seismic probes of stellar structures and ages. A closer look at the star’s flare activity may tell us something about conditions in its habitable zone, whether or not Gliese 581 c is actually within that zone. According to Matthews, MOST will release preliminary findings on the investigation some time next month.