They develop a new instrument to locate small habitable worlds

The Keck Planet Finder (KPF) instrument, which uses the “wobble” or radial velocity method of searching for planets, achieved so-called first light on November 9, meaning it captured its first data from the sky, in this case from planet Jupiter. While KPF will routinely observe stars, the KPF team chose to celebrate KPF’s planet-seeking capabilities by directly observing Jupiter in our own solar system.

“The advent of KPF marks an important and exciting step forward in our ability to advance the search to eventually find habitable Earth-like planets around other stars,” Hilton Lewis, director of the Keck Observatory, said in a statement. “We have been looking forward to KPF for almost a decade and are delighted to be able to take our already successful exoplanet discovery program to the next level.”

The search for small Earth-like planets, the most promising in the search for extraterrestrial life, has been limited by the tiny effects these planets have on their host stars.

KPF detects planets by looking for the periodic motions of their host stars caused by the planets as they orbit around and gravitationally “pull” on the stars. When the stars move from side to side, or wobble, their light shifts in the same way that the sound of a siren changes frequency depending on whether the noise is moving away from you or towards you, which is known as Doppler shift.

KPF will detect planets by looking for this stellar wobble in the spectra of stars (a spectrum shows the different frequencies of light from a star). The less massive the planet, the less wobble that occurs. The instrument’s cutting-edge technology means it can detect planets as small as Earth, and even smaller in some cases.

It can also detect Earth-mass planets in the habitable zones of smaller, cooler stars, though it still can’t see them in the habitable zones of Sun-like stars. A habitable zone is the region around a star where temperatures they are suitable for liquid water, a necessary ingredient for life as we know it.

In addition to discovering new planets, the instrument will determine the compositions of up to thousands of known planets and solve mysteries about the amazing diversity of planetary systems identified so far. KPF will also discover nearby planets that are ideal candidates for future imaging by other telescopes, such as the planned Thirty Meter Telescope, which could take direct images of planets orbiting alongside their stars.

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