The recent discovery of an exoplanet by the Habitable-zone Planet Finder (HPF), known as G 9-40b, is making waves in astronomical circles. This planet is orbiting a bright, low mass M-dwarf star, which is only 100 light years away from Earth. And it only takes 6 Earth-days to complete one orbit. What adds more interest to this discovery is G 9-40b is numbered among the top 20 closest transiting planets. NASA’s Kepler mission’s keen observation of a dip in the host star’s light led to this discovery, which was then confirmed using the HPF.
Understanding G 9-40b
G 9-40b is an exoplanet, a term used to describe planets outside our Solar System, discovered by the HPF. The first confirmation of an exoplanet happened in 1992. Due to their distance and the brightness of the stars they orbit, exoplanets are near impossible to see directly with telescopes. Instead, astronomers observe the effects these planets have on their stars.
The Role of the Habitable-zone Planet Finder
The HPF is an astronomical spectrograph, a vital tool in this discovery. This instrument was constructed by scientists at Penn State University before being installed on the 10-meter Hobby-Eberly Telescope situated at the McDonald Observatory in the United States. The main function of the HPF involves searching for exoplanets by employing the Doppler effect.
A spectrograph breaks up light into its component wavelengths. By measuring the properties of light over specific parts of the spectrum, astronomers can deduce what is responsible for the patterns they observe. The HPF is designed to provide the highest precision measurements of infrared signals coming from low-mass stars close to Earth. This technological wonder is now surveying the closest M-dwarfs, the most prevalent stars in the galaxy, with the aim of finding more exoplanets.
What is the Doppler Effect?
The Doppler effect refers to the change in frequency of sound, light, or other waves as the source and observer move towards or away from each other. This phenomenon is noticeable in the sudden change of pitch heard in a passing siren or the red shift observed by astronomers.
About M-dwarfs
M-dwarfs, or M-type stars also known as Red Dwarf Stars, are the most common type of star in the universe and the smallest type of hydrogen-burning star. Their mass ranges between 0.08 to 0.6 times that of the Sun, and form about 70% of the stars in our Milky Way Galaxy.
The Importance of the Goldilocks Zone
The HPF is designed to locate and characterise planets situated in the habitable-zone, also known as the “Goldilocks zone”. This region around a star has the potential to sustain liquid water on a planet’s surface because it is neither too hot nor too cold, but just right. The main role of the HPF is to confirm the presence of an exoplanet by ruling out any false positives with a high degree of certainty.