It Came From Another Galaxy

For the first time astronomers have discovered a planet in the Milky Way with extragalactic origins. It orbits a star that was most likely ripped from a satellite galaxy 6 billion to 9 billion years ago. Johny Setiawan and his colleagues homed in on the star HIP 13044, about 2,000 light-years away from Earth, its part of a stream of stars called Helmi that is believed to have originated in another galaxy. The researchers found the planet by monitoring HIP 13044 long enough to detect telltale wobbles indicating the tiny tug of an unseen body. The star is unusual because it has the lowest abundance of metals of any star known to have a planet. Also unusual is that HIP 13044 is old enough to have exhausted its supply of hydrogen fuel and passed through the red giant phase of evolution, in which it mushroomed in size. Since then the star has contracted to a diameter about seven times that of the sun and is now burning helium at its core. A star in this phase of evolution has never before been found to have a planet.

This experiment is an example of discovery science. This find is an interesting find, and a can be a step to learn about other galaxies. Through this discovery we can learn about different galaxies.

Author: Ron Cowen

Title of Article: It Came From Another Galaxy

Journal: Science News

Date: December 18, 2010

Page: 11