The Keck Planet Finder achieved first light on November 9, 2022 after capturing a spectrum of … [+]
A strange new image of the giant planet Jupiter was published today that will, say scientists, help them identify Earth-like planets orbiting distant stars.
The odd image from the W. M. Keck Observatory in Maunakea, Hawaii comes from “first light” of its new intrument, the Keck Planet Finder, which is expected to revolutionize the hunt for life beyond Earth from spring 2023 onwards.
Why the colored lines instead of the giant planet’s recognizable bands of cloud and its “Great Red Spot” storm? The Keck Planet Finder is now the world’s most advanced spectrometer for visible wavelengths.
Astronomy is merely the study of light. A spectrometer disperses light from an object into a spectrum—a bit like a rainbow. It allows astronomers to discover the gases and chemicals in the atmospheres of stars and planets. Some cold be “biosignatures”—signs of life on the surface of a planet.
Its images may not immediately be interesting to the layperson, but they could be of incredible value in the search for life beyond Earth. Earth-sized planets around other stars are extraordinarily difficult to detect due to their small size, which is why the Keck Planet Finder is big news.
About one in five Sun-like stars has an Earth-sized planet in its so-called “habitable zone” where it’s warm enough for liquid water to exist on the surface.
“We are the first generation who will really understand other planets in our galactic neighborhood,” said Sherry Yeh, deputy instrument scientist for Keck Planets Finder at Keck Observatory.
The Keck Planet Finder has been on the drawing board for almost a decade. “Seeing KPF’s first astronomical spectrum was a moving experience,” said Andrew Howard, KPF principal investigator and a professor of astronomy at Caltech. “I’m excited to use the instrument to study the great diversity of exoplanets and to tease apart the mysteries of how they formed and evolved to their present states.”
The Subaru, Keck I and Keck II Telescopes at the Mauna Kea Observatories at Sunset on the Big Island … [+]
When new telescopes and astronomical instruments come online astronomers tend to test and show-off their capabilities with a series of “first light” images. The Jupiter spectrum is such an image, included for its technical purity rather than its scientific worthiness. It was taken on November 9, 2022, as was a spectrum for a star called 51 Pegasi in the constellation of Pegasus, which hosts 51 Pegasi b, the first planet orbiting a Sun-like star (an exoplanet) ever discovered, in 1995.
Also called “Dimidium,” its discoverers Michel Mayor and Didier Queloz in 2019 shared the Nobel Prize in Physics. In the years since over 5,000 exoplanets have been discovered. 51 Pegasi b is a so-called “hot Jupiter,” but Keck Planet Finder is expected to study Earth-like planets out there—and in incredible precision.
“Prior to the recent exoplanet discovery boom over the last two decades, we did not really know what other planets were out there [and] whether our own solar system or our own Earth were common,” said Yeh.
The new telescope’s spectrums will be used to find exoplanets using the Doppler effect to measure the radial velocity of the host star over time. A star’s motion reveals the gravitational pull of any planets orbiting around it. A star wobbles if there are planets in orbit because they all orbit a common center of mass away from the star’s center of mass.
Keck Planet Finder will look for this stellar wobble, which astronomers can measure to infer the mass and density of orbiting planets. Its genius is in its unprecedented precision, which will enable it to study less massive planets that causes smaller “wobbles” in their host stars. Once fully-commissioned the new instrument will be able to detect stars moving back and forth at a rate of only 30 centimeters/second. That’s about 10 times more powerful than any other similar instrument currently in use.
Wishing you clear skies and wide eyes.
