UNIVERSITY PARK, Pa. — The exoplanet-hunting instrument NEID, designed and built at Penn State, has passed an important milestone on the road to discovering Earth-mass planets beyond our solar system.
The new instrument, an extreme precision radial velocity spectrometer, has been installed on the 3.5-meter WIYN telescope at Kitt Peak National Observatory in southern Arizona, a program of the National Science Foundation's National Optical-Infrared Astronomy Research Laboratory, and has made its first observations collecting starlight.
The NSF-NASA funded instrument is designed to measure the motion of nearby stars with extreme precision — roughly three times better than the previous generation of state-of-the-art instruments — allowing researchers to detect, determine the mass of and characterize exoplanets as small as Earth.
NEID detects exoplanets by measuring the subtle effect these planets have on their parent stars. Planets tug gravitationally on the stars they orbit, producing a small “wobble” — a periodic shift in the velocity of the star. This happens in our own solar system — Jupiter causes the sun to wobble at roughly 13 meters per second — about 43 feet per second, only a bit faster than record-breaking sprinter Usain Bolt — whereas the Earth causes a movement with a velocity of only 0.1 meters per second — less than 4 inches per second. The amplitude of the wobble is proportional to an orbiting planet’s mass, meaning NEID measurements can be used to determine the masses of exoplanets. Most current instruments can measure velocities as low as 1 meter per second — just over 3 feet per second, a slow walking pace, but NEID was built to detect even lower velocities — potentially uncovering Earth-mass exoplanets.
“In the last decade the state of the art has been roughly 1 meter per second,” said Jason Wright, professor of astronomy and astrophysics and NEID project scientist at Penn State. “NEID is expected to do about three times better, pushing the envelope to higher precision.”