Discovery News: Space Diary

Little Leo

Twinkle, twinkle little star
Are you hiding planets afar?

More and more often, the answer is turning out to be “yes.” The latest discovery: a world just five time larger than Earth circling around its mother star in the constellation Leo. If true, the planet would be the smallest yet found beyond our solar system. More importantly, researchers believe the planet to be of the terrestrial, or rocky body, variety.

A team of astronomers from the Spanish Research Council working with Dr Jean-Philippe Beaulieu, a visiting astrophysicist at University College London, made the discovery using a computer simulation that predicted the planet’s location based on small changes on an already discovered sibling planet.

The scientists say the newly discovered world, called GJ 436c, orbits its host star in 5.2 Earth days and completes a revolution in 4.2 Earth days.

“On Earth, a full day (sunset to sunset) coincides quite closely with the rotation period. On the new planet these two periods do not coincide, since the orbital translation period and the rotation period are very similar. For this reason, a full day on the new planet would take four planetary years, or roughly 22 Earth days,” notes a press release about the discovery.

The study is published in this week’s Astrophysical Journal.

Sheep in space

The announcement this week that scientists using the Hubble Space Telescope have found organic molecules in the atmosphere of a planet outside the solar system reminded me of an interview I had a while back about how researchers might determine if life exists on other planets.

I asked if extraterrestrial scientists were looking at Earth, for example, would they know it was populated. Apparently, one of the give-aways would be the same chemical found in the atmosphere of planet HD 189733b -- methane. We can thank the sheep and cows for providing telltale signs of life on Earth.

It’s doubtful any alien livestock are busy processing dinner on HD 189733b, however. The planet is too close to its mother star to support life as we know it.