New Automated Planet Finder finds two new planetary systems

Lick Observatory's newest telescope, the Automated Planet Finder (APF), has discovered two new planetary systems, in its first months of operation.

The APF has been operating robotically night after night on Mt. Hamilton since January, searching nearby stars for Earth-sized planets. Every night the fully autonomous system checks the weather, decides which stars to observe, and moves the telescope from star to star throughout the night, collecting measurements that will reveal the presence of planets. Its technical performance has been outstanding, making it not only the first robotic planet-finding facility but also one of the most sensitive.

The search for planets beyond our solar system (called "extrasolar planets" or "exoplanets") has yielded a huge number of discoveries in recent years, especially since NASA's Kepler spacecraft joined ground-based telescopes in the effort. Unlike Kepler, however, which focused on distant stars in one small patch of sky, the APF focuses on nearby stars and covers the entire sky.

Steve Vogt, professor of astronomy and astrophysics at UC Santa Cruz, who led the 12-million-dollar-APF project and designed the Levy spectrometer at the heart of the system.

The APF facility consists of a 2.4-meter telescope and the Levy Spectrometer, which Vogt designed and optimized specifically for planet hunting. The spectrometer takes starlight from the telescope and spreads it into a rainbow of colors, splitting the light into a spectrum of thousands of different wavelengths that can be measured with great precision. Repeated measurement of a star's spectrum enables astronomers to detect the tiny wobble induced in a star by the gravitational tug of an orbiting planet.

A paper on the APF itself will be published April 1 in Publications of the Astronomical Society of the Pacific.