Dense exoplanet gets the lead out and in

Sometimes it pays to look over some older data and re-examine it. An exoplanet called 55 Cancri e was thought to have an orbit that was just 2.8 days long when it was discovered. However, two researchers looked over the data and realized they got a better fit if the orbit were actually only 0.73654 days — just under 18 hours! This meant it orbited its star far closer than previously thought as well.

And while that may be somewhat interesting, it’s the implications for the planet itself that make this orbital revision so cool. Or actually, hot. And dense.

Right. As usual, there’s a story to tell here…

The planet was discovered using the Doppler method: as it orbits its star, the gravity of the planet tugs on the star, causing a very small shift in the spectrum of starlight. The problem is getting enough observations to nail down the planet’s period; you can’t observe when it’s up during the day, and that cuts into the ability to get a good sampling of measurements. The discovery data gave a good fit at 2.8 days, so that’s what ...

Full story at http://blogs.discovermagazine.com/badastronomy/2011/05/05/dense-exoplanet-gets-the-lead-out-and-in/