ND astronomer finds two new planets

Author: John Monczunski

So maybe our solar system isn’t so special after all. In February, an international team of astronomers that includes Notre Dame’s David Bennett, announced the discovery of two planets in a distant solar system similar to ours, 5,000 light years from Earth.

Using a technique known as “gravitational microlensing” in which the gravitational field of one star acts as a lens, bending and magnifying light from another star, astronomers discovered “blips” in their data that indicated the presence of the two planets about the size of Jupiter and Saturn orbiting a red dwarf star about half the size of our sun.

It took the astronomers two months of analysis to realize precisely what they had found. The discovery process began one night in 2006 when some Polish astronomers using a telescope in Chile found a microlensing alignment of two stars in the constellation Sagittarius. Over the course of the next 11 days, astronomers across the world locked onto the coordinates, gathering data.

For the next two months, scientists crunched the numbers with sophisticated computer programs. Initial calculations by Scott Gaudi of Ohio State University indicated that the observed variations in brightness were caused by a Saturn-like planet. However, observatories in Chile and Israel detected additional brightness, which suggested an additional Jupiter-sized planet.

Bennett, a research associate professor of astrophysics at Notre Dame, conducted a more detailed analysis of the data that revealed the orbital motion of the Saturn-like planet. The newly found planets are the first two discovered simultaneously by gravitational microlensing. Four single planets previously have been found by the method.

John Monczunsk is an associate editor of this magazine. Email him at monczunski.1@nd.edu.