There’s a new headache for astronomers wanting to image Earth-like planets. Exozodiacal light.
This phenomenon is similar to the one seen on earth (zodiacal light), but a lot brighter. It appears as a faint white glow in the night sky after sunset, or just before dawn.
Using ESO’s Very Large Telescope, astronomers found exozodiacal light in nine star systems near their habitable zones.
Here’s what zodiacal light looks like taken from Earth.
And, this is an artist impression of the brighter exozodiacal light as seen from the surface of an exoplanet.
The latest observations were taken through the ESO’s Very Large Telescope Interferometer (VLTI), at the Paranal Observatory in Chile, in near-infrared light. The team of astronomers used the 1.8 meter Auxiliary Telescopes to feed light to the VLTI. Then they were able to separate the relatively faint glow of exozodiacal light from the light of the nearby star.
“If we want to study the evolution of Earth-like planets close to the habitable zone, we need to observe the zodiacal dust in this region around other stars,” said Steve Ertel, lead author of the paper. “Detecting and characterising this kind of dust around other stars is a way to study the architecture and evolution of planetary systems.”
The team was surprised by what they found. Most of the exozodiacal dust was detected around older stars. This runs against the understanding that dust production slows in planetary systems over time.
“The high detection rate found at this bright level suggests that there must be a significant number of systems containing fainter dust, undetectable in our survey, but still much brighter than the solar system’s zodiacal dust,” said Olivier Absil, co-author of the paper. “The presence of such dust in so many systems could therefore become an obstacle for future observations, which aim to make direct images of Earth-like exoplanets.”