SSS 2010-11-18(在线收听

This is Scientific American’s 60-Second Science. I’m Christopher Intagliata. Got a minute?
Astronomers have already discovered hundreds of exoplanets. But make way for the new kid, which is orbiting a kind of star that models say it shouldn’t.
Researchers found the exoplanet while looking at the star HIP 13044—or Sergio, for Star of Extra-Galactic Origin. It’s in what once was a separate galaxy, which the Milky Way gobbled up billions of years ago.
The scientists saw Sergio wobbling due to the gravitational tug of a Jupiter-sized gas planet, which the scientists dubbed Sergio Junior. They detail their find in the journal Science.
You don’t ordinarily find planets hanging around a star like Sergio. First, it's really old—past the Red Giant phase, when stars balloon in size and swallow up planets in close orbits. And planets tend to form around metal-rich stars, like our Sun. But Sergio has only one percent the metal content of our Sun. That doesn't jibe with one widely accepted model of planetary formation.
The Sergios may offer a glimpse of the future of our own planetary system—in about five billion years. We hope to be back then with an update.
Thanks for the minute. For Scientific American’s 60-Second Science, I’m Christopher Intagliata

  原文地址:http://www.tingroom.com/lesson/sasss/2010/11/125108.html