An artist's conceptions depicts the probable planet orbiting the star GJ 411, which lies just 8.3 light-years from Earth.Ricardo Ramirez

Astronomers have spotted more than 100 new potential alien planets, including one in the fourth-closest star system to the sun, a new study reports.

This haul of newfound possible exoplanets, which have yet to be confirmed as bona fide alien worlds, comes from a new analysis of 20 years' worth of data gathered by the HIRES (High Resolution Echelle Spectrometer) instrument at the Keck Observatory in Hawaii.

"HIRES was not specifically optimized to do this type of exoplanet detective work, but has turned out to be a workhorse instrument of the field," study co-author Steve Vogt, of the University of California, Santa Cruz, said in a statement. "I am very happy to contribute to science that is fundamentally changing how we view ourselves in the universe," added Vogt, who designed and built HIRES.

HIRES detects exoplanets using the "radial velocity" method: The instrument picks up the tiny gravitational wobbles that orbiting worlds induce in their parent stars. This strategy is different from that employed by the most prolific planet hunter of all time, NASA's Kepler space telescope; Kepler watches for the tiny brightness ...