A new extreme precision radial velocity spectrometer is planned for the Kitt Peak National Observatory. The instrument will augment the existing 3.5-meter WIYN telescope and be used to measure the slight motion of stars caused by their orbiting planets, according to a press release by the National Optical Astronomy Observatory (NOAO).
The NOAO is operated by Association of Universities for Research in Astronomy Inc. under a cooperative agreement with the National Science Foundation (NSF). NSF operates Kitt Peak.
NSF and NASA have joined forces in the study of exoplanets (NASA-NSF Exoplanet Observational Research, NN-EXPLORE).
The Extreme Precision Doppler Spectrometer (EPDS) will measure stellar radial velocities in a way that will allow NSF and NASA to identify Jupiter- and Neptune-size gas giant planets and super-Earth and Earth-size rocky planets. When a planet orbits a star, the gravitational pull and mass of the planet induces the star to "wobble," so a lower-mass planet would cause less of a wobble than a planet will a larger mass.
The spectrometer will be able to identify minimum velocities of 0.5 m/s (1 mph) with a goal of 0.1 m/s (0.2 mph). For perspective, a desert tortoise moves at about 0.2 mph and a gila monster's top speed is 1 mph
Jupiter causes a 13 m/s (29 mph) amplitude wobble in the Sun, and the Earth causes a much smaller wobble (about 0.1 m/s). To characterize rocky Earth-sized planets, the "extreme precision" part of the spectrometer is crucial.
"Once we measure a planet's mass, we can use what we know about the planet's size, as measured by Kepler and TESS, to infer whether the planet is rocky like the Earth or gaseous like Jupiter," said Kitt Peak Director Lori Allen, according to the press release.
"NASA and the NSF are excited to team up to advance humankind's understanding of planets around other stars," said Doug Hudgins, Program Scientist for NASA's Exoplanet Exploration Program. "The new EPDS spectrometer will give the US science community access to a world-class instrument for years to come."
The new spectrometer will be included in the Guest Observer program in 2018.
