Astronomers from the world over meet in Nantes, France, this week to attend the joint Division of Planetary Sciences meeting and the European Planetary Science Conference. A news item announced yesterday, and a session on educational programs that make a global impact that took place yesterday as well, are already of interest to us.
First, a team of researchers led by Bill Cochran of the University of Texas at Austin announced they discovered an unusual multiple-planet system using NASA’s Kepler spacecraft, containing a super-Earth and two Neptune-sized planets orbiting in perfect resonance with each other. Kepler uses the ‘transit method’ to look for planets by monitoring a star’s brightness over time. Periodic dips in brightness could indicate that a planet passes in front of the star. To prove that the signature decrease in brightness actually arises from a transiting planet, and isn’t mimicked by something else, follow-up work is done by scientists using ground-based telescopes, including Austin’s McDonald Observatory.
Cochran’s team found that three planets orbit Kepler-18, a star similar to the Sun. Two of these, designated c and d, proved their planet credentials up front via an orbital 2:1 resonance; planet c orbits the star twice for every one orbit d makes. Interacting with each other, they had to be in the same planetary system for the resonance to occur. Planet b was confirmed using a process called ‘planet validation,’ ruling out the possibility that the regular variation of the star’s brightness is caused by a background object.
The session on educational programs started with Mike Simmons of Astronomers without Borders, under whose aegis the Transit of Venus Project is run. Next to other programs of AWB, like Global Astronomy Month and The World at Night, Mike also featured the unprecedented program AWB is now preparing for students to follow in the footsteps of scientists who in the ancient and modern worlds have spent centuries finding and refining the size of the Earth and the scale of the Solar System. There will be a series of projects with students observing from around the world, the culmination of which is the transit of Venus on 5 and 6 June, 2012.
Next Thursday there will be a session discussing the latest developments in outreach activities for promoting public engagement in two areas: lunar science and the transit of Venus. Here, Lou Mayo, Jean-Eudes Arlot and Jay Pasachoff will cover the transit of Venus in three successive talks. I’ll keep you updated!