The hunt for more planets to call home
Fasten your seat belts, Earthlings, because early in 2018, Penn State scientists will start using the first of two new space-exploration instruments to hunt for nearby planets in regions around their star where liquid water may exist— possibly being capable of supporting life.
The “Habitable Zone Planet Finder” is the name of the first of these two instruments, both of which soon will begin scanning our galaxy for habitable-zone planets. The name of the second instrument, “NEID,” is a word meaning “to discover” or “to visualize” in the native language of the Tohono O’odham, on whose land NEID will conduct its survey as part of a telescope at Kitt Peak National Observatory. Both instruments were built at Penn State.
Habitable Zone Planet Finder
Suvrath Mahadevan, associate professor of astronomy and astrophysics, is leading the team that designed and developed the Habitable Zone Planet Finder specifically to discover habitable planets orbiting stars near our solar system that are smaller and fainter than our Sun. Variations in the light from one of these stars could be clues that it has orbiting planets.
These stars, known as “M dwarfs,” are intriguing because they are the most numerous in our galaxy, because they could power life on planets located at just the right distance for holding liquid water, and because they have been very hard to study. Most of the light that M dwarfs emit is in the infrared wavelengths of electromagnetic radiation—longer than the wavelengths of visible light that human eyes can see.
“The Habitable Zone Planet Finder will allow us to detect the existence of planets that are similar in mass to Earth and that also are in orbits where liquid water can exist on their surfaces,” Mahadevan said.
The Habitable Zone Planet Finder has been completed and now is being installed as a component of one of the three largest optical telescopes on Earth, the William P. Hobby– Robert E. Eberly Telescope, located in a remote area of West Texas where night skies are among the darkest in the continental United States. Two Penn State astronomers invented this telescope’s innovative design. Penn State and four other universities built it during the 1990s and continue to operate it.
The planet finder’s multiyear hunt will begin early in 2018—after just one more component is added—a “laser frequency comb” developed by the National Institute of Standards and Technology. This “comb” separates individual wavelengths of electromagnetic energy from the stars—including the infrared light that human eyes cannot see—into separate lines so scientists can see the star’s individual wavelengths in a way that is useful for their research.
With the addition of the laser frequency comb, the Habitable Zone Planet Finder will be a world-class “echelle spectrograph” capable of revealing the invisible rainbows of electromagnetic energies emitted by M dwarf stars near our solar system. The Habitable Zone Planet Finder is expected to match or exceed the precision of any other existing infrared instrument for astronomy research.
NEID
The Habitable Zone Planet Finder’s sister instrument, NEID, now is being built at Penn State by another team led by Mahadevan, with funding from NASA’s Jet Propulsion Laboratory and Astrophysics Division. NEID also is an echelle spectrograph, like the Habitable Zone Planet Finder, but is designed to detect optical light—the kind that human eyes can see.
“This optical instrument is expected to be more precise than the Habitable Zone Planet Finder, since it needs to be so in order to find terrestrial planets around Sun-like stars,” said Fred Hearty, NEID project manager and senior scientist in Penn State’s Department of Astronomy and Astrophysics. NEID will detect planets by the tiny gravitational tug they exert on their stars.
NEID is scheduled for delivery in the fall of 2018 to the WIYN Telescope at Kitt Peak in Arizona, one of the two largest optical telescopes there. When completed in 2019, the instrument will be the centerpiece of a partnership between NASA and the National Science Foundation, called the NASA-NSF Exoplanet Observational Research program (NN-EXPLORE). The Penn State team then will begin a five-year hunting expedition with NEID for planets that are at the correct distance from their host stars to potentially have just the right conditions for supporting life.
