Very Large Telescope Spots Exozodiacal Light Among Nearby Stars

Scientists have spotted exozodiacal light with the help of the Very Large Telescope Interferometer (VLTI). Using the instrument, astronomers observed 92 nearby stars and discovered bright exozodiacal light, created by the glowing grains of hot exozodiacal dust around nine of the stars.

Zodiacal light looks like a faint diffuse white glow seen in the night sky after the end of twilight, or before dawn. It's created by sunlight reflected off of tiny particles and appears to extend up from the vicinity of the sun. This reflected light isn't just observed from Earth, but can also be seen from everywhere in the solar system.

Exozodiacal light, however, is a much more extreme version of this phenomenon. While it's been previously detected, this is the first large study of it around nearby stars. The scientists viewed dust created in collisions between small planets-objects called planetesimals that are similar to the asteroids and comets of the solar system.

"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 new paper, in a news release. "Detecting and characterizing this kind of dust around other stars is a way to study the architecture and evolution of planetary systems."

The scientists analyzed the properties of the stars surrounding by a disk of exozodiacal dust. This showed them that most of the dust was detected around older stars. This, in particular, raises some questions when it comes to understanding planetary systems. Any known dust production caused by collisions of planetesimals should diminish over time as the number of planetesimals is reduced as they're destroyed.

The findings reveal a bit more about stars and exozodiacal dust. This, in turn, sheds a bit more light on the evolution of planets and stars in our solar system.

"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 new 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."

The findings are published in the journal Astronomy & Astrophysics.