A few exoplanet discoveries kicked off the press conference portion of the American Astronomical Society (AAS) meeting. (Worlds around other stars is a hot topic.) The first presentation came from a study that didn’t find what it was supposed to find. Edward Guinan of Villanova University announced that an undergraduate research project to determine the age of planet-hosting stars turned into quite the discovery. The team found out that there’s a lot of magnetic interaction between one particular star and its planet. (They were looking at the “famous” hot Jupiter HD 189733b and its star HD 189733A.) The star is taking material from the planet and is “spinning up.” This causes it to look much younger than the other star in the system, HD 189733B (that’s an uppercase B).
Kepler-10b is a rocky exoplanet that measures 1.4 times the size of Earth and 4.6 times its mass. NASA image
Later in the same press conference, we learned about
a Kepler find. This mission is expected to haul in hundreds of exoplanets (back in June, scientists with the mission revealed they already had some 706 exoplanet candidates). Kepler researcher Natalie Batalha announced that the Kepler team had discovered a planet just 1.4 times the diameter of Earth. The planet (Kepler-10b) isn’t exactly habitable — it’s so close to its star that it orbits in 0.84 Earth day, and its sun-facing side has a temperature of 2500° Fahrenheit (1370° Celsius). Scientists used the planet’s mass and radius to determine its density, which is higher than Earth’s. They think this world contains more iron and nickel than our planet.
Kepler-10b dimmed the light from its star by just 1.5 parts in 10,000. This sensitivity is what makes the Kepler mission (and this discovery) so awesome. At the press conference, scientists talked about the possibility of this super-Earth being the stripped-down core of a hot Jupiter. Whatever it is, the astronomers agreed that it’s a pretty awesome discovery.
The rest of the day’s topics shifted gears — to the high-energy world and black holes. I’m a sucker for particle astrophysics, so the press conference for the Fermi Gamma-ray Space Telescope had me hooked. But no one could deny how cool their discovery was: Fermi scientists detected positrons (the electron’s antiparticle) associated with thunderstorms.
In December 14, 2009, there was an intense thunderstorm above southern Africa. The lightening produced gamma rays, which then interacted with air particles to create electrons and positrons. These charged particles traveled along Earth’s magnetic field lines to where Fermi detected them, some 2,800 miles (4,500 kilometers) away. So, gamma-ray astrophysicists discovered an Earth-science phenomenon — it’s great when findings can reach multiple areas of science. Fermi has actually observed about 130 terrestrial gamma-ray flares, but this was the first where it detected antimatter.
The day involved a number of other announcements (many of which have been posted to the Astronomy magazine news page) and a few invited talks. Interestingly, the afternoon ones had much higher attendance rates than the 8:00 a.m. talk. Astronomers don’t seem to like the mornings — who would’ve thought. It was a busy day, and I’m sure today will be just as crazy.
Related blog:
American Astronomical Society meeting: January 9, 2011