Exozodiacal light could be hiding Earth-like planets in other solar systems from being spotted by astronomers. Dust from the collision of asteroids can combine with material from the slow evaporation of comets, and reflect light from the local star. Astronomers believe this can create a glow, called exozodiacal light, which could prevent detection of small, rocky exo-planets around alien suns.
The Very Large Telescope Interferometer (VLTI) in Chile was utilized to observe 92 local star systems, searching for the glow from these clouds. This data was then combined with older studies, in order to produce a more complete picture. Researchers discovered the formations surrounding habitable zones in nine of the alien star systems.
Zodiacal light can be observed from areas with extremely dark skies, as a white glow near the Sun, just before sunrise or immediately following sunset. This white glow is usually triangular, and appears to extend directly up from the Sun. It is caused by sunlight reflecting off gas and dust that orbits close to our companion star, bouncing toward the Earth. This marks the first time that this phenomenon, long-known on Earth, has been recorded in extraterrestrial solar systems.
The VLTI interferometer combined images from four telescopes, each having a diameter of 71 inches. This system allowed astronomers to study their target with as much detail as an instrument having a diameter equal to the distance between the telescopes.
Dust surrounding other stars is usually studied to investigate how the material could be forming new alien worlds. However, this new study was unique in examining how the study of extra-solar planets may be hindered by the material.
"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. 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," Olivier Absil of the University of Liège and co-author of an article announcing the results of the study, said.
The Zodiacal light is sometimes known as "false dawn," since it can appear, at first glance, to be the Sun coming over the horizon. The effect is best seen just before dawn in autumn, and just after sunset during spring months, during which time the glow is often referred to as a false dusk. Zodiacal light was first described in print in 1661, and was the subject of a doctoral thesis by former Queen guitarist Brian May.
The European Organisation for Astronomical Research in the Southern Hemisphere (ESO) made research into exozodiacal light public on its Web site.
