The Kitt Peak National Observatory, on the Tohono O’odham reservation outside Tucson, will be home to a next-generation spectrometer and related system which will allow astronomers to detect much smaller exoplanets through the radial velocity method. P. Marenfeld (NOAO/AURA/NSF)
When the first exoplanet was identified via the radial velocity method, the Swiss team was able to detect a wobble in the star 51 Pegasi at a rate of 50 meters per second. The wobble is the star’s movement back and forth caused by the gravitational pull of the planet, and in that first case it was dramatic — the effects of a giant Jupiter-sized planet orbiting extremely close to the star.
Many of the early exoplanet discoveries were of similarly large planets close to their host stars, but it wasn’t because there are so many of them in the cosmos. Rather, it was a function of the capabilities of the spectrographs and other instruments used to view the star. They were pioneering breakthroughs, but they didn’t have the precision needed to measure wobbles other than the large, dramatic ones caused by a close-in, huge planet.
That was the mid 1990s, and radial velocity astronomers have worked tirelessly since to “beat ...