[curiousuburb]

Odds of Earthlike Exoplanet almost 1-in-4

... In general, small planets turned out to be much more common than large ones. The researchers extended that trend down to planets about half Earth’s mass. They found that about 23 percent (give or take about 10 percent) of sun-like stars should have a planet between half and twice the Earth’s mass orbiting very close in, about a quarter of the distance from the Earth to the sun. That distance would make the planets far too warm for liquid water. But because planets tend to be more abundant farther from their stars, Howard thinks there should be even more Earth-mass planets in cooler orbits where liquid water is stable. “I wouldn’t be surprised if the true number [of stars hosting Earth-mass planets] is one in two, or one in eight — but I’m almost sure it’s not one in 100,” he said. “That’s a really big improvement on our knowledge.” Surprisingly, the observations also showed a lot of planets between 5 and 30 times Earth’s mass, a range that theoretical models of planet formation predicted should be so empty it earned the name, “the planet desert.” “We showed that the desert is in fact closer to a tropical rain forest,” Howard said. The new numbers are a windfall to researches like Winn, who are involved in designing the next generation of planet-hunting telescopes. “It sets our expectations much more clearly than they were last week,” he said. “We were just guessing, to see how to design the instrument. Now we have some much more solid numbers to put in.” ... continues ...

Drake equation refinements keep getting more interesting.