Observatory Successfully Puts New Planet-Hunting Instrument To Test

An exciting new era has begun in the quest for Earth-sized planets orbiting neighboring stars, which are extremely challenging to discover given their tiny size, with the “first light” of new planet-hunting equipment at W. M. Keck Observatory. The Keck Planet Finder (KPF) is the most sophisticated high-resolution spectrometer for visible wavelengths, and it operates on the Keck I Telescope on Maunakea on the island of Hawai’i.

First light spectra of Jupiter and 51 Pegasi, host to the first planet circling a sun-like star to be found by the Doppler method, were both obtained by the KPF team last night, November 9, using the next-generation device. It is about beginning precise observations of other worlds in an effort to advance the search for life. One in five sun-like stars has Earth-sized planets in their habitable zones, where liquid water can exist in the atmosphere. This is crucial for the development of complex life.

Star movement

KPF will analyze and quantify exoplanets by observing how their host stars move and behave, a method first developed at Keck Observatory’s Doppler Telescope. Because of the planet’s gravitational pull, the star wobbles as it rounds the galaxy. The Kepler Space Telescope will search for this stellar wobble, which can be used by astronomers to deduce the mass and density of the planet pulling on the star.

The more difficult it is to detect the swaying of starlight, the smaller the planet’s mass and the smaller the star’s wobble. Once fully operational, KPF will be capable of detecting stars whose motions are as slow as 30 centimeters per second, making it a viable solution to this problem. Compare this to the High-Resolution Echelle Spectrometer (HIRES), the present planet-hunting instrument at Keck Observatory, which can detect stellar motions of only 200 centimeters/second, and you’ll get an idea of the strength of KPF.

The Zerodur glass-ceramic hybrid material used to create the renowned primary mirror segments at Keck Observatory is what gives this state-of-the-art spectrometer its distinctive appearance. Schott AG’s Zerodur is a temperature-resistant material that never loses its form. Because of the potential for thermal fluctuations to produce spurious signals that are misinterpreted as Doppler shifts from stars, KPF relies heavily on the instrument’s ability to maintain a constant temperature. KPF’s ability to detect and describe exoplanets is unrivaled because of the reduction in thermal motions that it provides.

Susan Kowal
Susan Kowal is a serial entrepreneur, angel investor/advisor, and health enthusiast.