More on the race to find Earth-like planets and the Kepler Mission

Monday, February 23, 2009

A planet around a red dwarf star. I expect Kepler's first discoveries of Earth-like planets will be around stars like these.

Here's something else to read from MSNBC on my favourite subject as we wait for terrestrial astronomers, COROT and the upcoming Kepler Mission to discover another Earth (and then more after that). The article notes that the first discoveries by Kepler will be of planets easiest to detect, hot Jupiters orbiting close to their star as they are both massive (dimming their star more than a smaller planet) and have very quick orbits (takes very little time to establish their presence).
The first fruits of the $550 million Kepler mission won't be the coolest alien Earths, Boss cautioned. "Often the oddballs are the earliest ones to find, for some reason," he said. Boss expects the Kepler team to announce the mission's first discoveries of hot Jupiters and hot super-Earths within a month after science operations begin.
Yes, and hot super-Earths as well. These will probably receive the most press at the beginning as even though they're not planets we can explore they're still closer in size and thus more novel than yet another hot Jupiter.

Only after that will we be able to start to find planets almost exactly like ours, with similar sizes and orbits around similar stars:
The biggest factor behind that schedule has to do with the time scale of a planet's orbit. It takes at least three orbits for astronomers to confirm that the dimming of the star is really caused by a planet rather than, say, the brightness cycles of a variable star or a binary-star system. If the planet is extremely close to its star - which would be an oddball orbit by solar system standards - that won't take long. For example, the hot super-Earth identified by Corot completes an orbit in just 20 hours.

The article doesn't mention it but I expect there will also be a number of Earth-like planets discovered before then in close orbits to their stars, but red dwarf stars instead of a G V star like our Sun, because their habitability zone is much closer in which means that planets in orbits around 0.1 AU or so (ten times closer than us) with really quick orbits around their red dwarf stars will be at just about the right range to have perhaps an earthlike environment. Gliese 581 d (orbits once every 83 days) and c (every 12 days) are a good example of this.

Because habitability of red dwarf systems is still a matter of debate, the discovery of these planets might not be the one discovery we're looking for to completely change our view of space, but it'll be the next best thing. The two planets around Gliese 581 certainly stirred up quite a bit of press when their discovery was announced.


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