Exoplanet Hunters Find a Chemical Clue

Montage of the HARPS spectrograph and the 3.6m telescope at La Silla. The upper left shows the dome of the telescope, while the upper right illustrates the telescope itself. The HARPS spectrograph is shown in the lower image during laboratory tests. The vacuum tank is open so that some of the high-precision components inside can be seen.
Credit: European Southern Observatory

European scientists recently used a telescope instrument called the High Accuracy Radial Velocity Planet Searcher (HARPS), to measure the chemical content of 500 stars similar to the Sun, some with known planetary systems and others without. They discovered that all the stars that host planets have a curious characteristic in common with our Sun: low levels of the element lithium.

While much more remains to learned about why stars with planets share this trait, researchers are heartened that they could use HARPS and similar instruments to quickly find other planets beyond our Solar System.