Habitable-zone Planet Finder (HPF)


At 100 light-years from Earth, a low-mass star was sending signals in a pattern that suggested that an exoplanet was orbiting the star confirmed the Habitable-zone Planet Finder (HPF).

Habitable-zone Planet Finder

  • NASA’s Kepler mission observed a dip in the host star’s light, suggesting that the planet was crossing in front of the star during its orbit.
  • To confirm, researchers turned to an instrument called Habitable-zone Planet Finder (HPF). It has confirmed that there is indeed an exoplanet.
  • HPF is an astronomical spectrograph, built by Penn State University scientists, and recently installed on the 10m Hobby-Eberly Telescope at McDonald Observatory in Texas.
  • The instrument is designed to detect and characterize planets in the habitable zone — the region around the star where a planet could sustain liquid water on its surface — around nearby low-mass stars.
  • The newly confirmed planet, called G 9-40b, is the first one validated by HPF. It is about twice the size of Earth and orbits its star once every six Earth-days.

How it works?

  • A spectrograph is an instrument that splits light into its component wavelengths.
  • Scientists then measure the properties of light over a specific portion of the spectrum and draw conclusions on what is responsible for the trends they observe.

Why need HPF?

  • Kepler’s observations alone were not enough to confirm a planet. It was possible that a close stellar companion was responsible for the dip in the star’s light.
  • Precision spectroscopic observations from HPF ruled out this possibility.
  • Shooting a high-power laser into the air, researchers generated a “laser guide star”, and subsequent observations found no evidence of blending of light or other stellar companions.
  • Finally, using HPF, an analysis of a set of radial velocities helped provide estimates for the planet’s mass.


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