Astronomers Discover Ancient Planets From the Early Universe
Posted on March 29, 2012
European astronomers have discovered an ancient planetary system they think is likely to be a survivor from one of the earliest cosmic eras, 13 billion years ago. The system consists of the star HIP 11952 and two planets, which have orbital periods of 290 and 7 days, respectively. An artist's impression of HIP 11952 and its two Jupiter-like planets is pictured above.
The star HIP 11952 contains very little other than hydrogen and helium. This is unusual as statistically, a star that contains more heavier metals is more likely to have planets. The system promises to shed light on planet formation in the early universe, when the universe contained almost no chemical elements other than hydrogen and helium.
Researchers from the Max-Planck-Institute for Astronomy in Heidelberg, Germany, identified two giant planets around the star HIP 11952 at a distance of about 375 light-years from Earth. By themselves, these planets, HIP 11952b and HIP 11952c, are not unusual. What is unusual is the fact that they orbit such an extremely metal-poor and extremely old star.
Veronica Roccatagliata (University Observatory Munich), the principal investigator of the planet survey around metal-poor stars that led to the discovery, says, "In 2010 we found the first example of such a metal-poor system, HIP 13044. Back then, we thought it might be a unique case; now, it seems as if there might be more planets around metal-poor stars than expected."
Johny Setiawan of the Max Planck Institute for Astronomy, who led the study of HIP 11952, says, "This is an archaeological find in our own backyard. These planets probably formed when our Galaxy itself was still a baby."