Researchers detected exozodiacal light reflected off hot dust in the habitable zone of nine stars.
Zodiacal light is created by starlight bouncing off the dust, and can be seen in the sky at the end of dusk or just before dawn, the European Southern Observatory reported. Exozodiacal light is a much more extreme version of this phenomenon. The findings were made using the Very Large Telescope Interferometer (VLTI).
In the past researchers have observed dust that they believe will one day form into planets, but the recent analysis looked at dust created by the collision of super-small planets called planetesimals; this type of light is the origin of zodiacal light in 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 paper, from ESO and the University of Grenoble. "Detecting and [characterizing] this kind of dust around other stars is a way to study the architecture and evolution of planetary systems."
Detecting this light required high resolution observations through interferometry, which is when light is collected at the same time with multiple telescopes and combined. Using the VLTI the researchers were able to reach a performance level 10 times higher than instruments in the past.
Through their observations the researchers noticed most of the dust was detected around older stars. This finding is interesting because dust production caused by collisions of planetesimals should diminish over time. Exozodiacal dust emission make it difficult to detect Earth-like planets with direct imaging. The number of stars containing zodiacal light in the solar system is most likely significantly higher than what has been seen in the survey, meaning these studied are the first steps towards understanding exozodiacal light.
"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, from the University of Liège. "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."
