Sun-like stars not all that dusty

Sun-like stars are not all that dusty, reveals a new study, adding that less dust means better odds of snapping clear pictures of the stars' planets in the future.

"Dust is a double-edged sword when it comes to imaging distant planets. The presence of dust is a signpost for planets but too much dust can block our view," said Bertrand Mennesson from NASA's Jet Propulsion Laboratory, Pasadena, California.

These results come from surveying nearly 50 stars from 2008 to 2011 using the Keck Interferometer, a former NASA key science project that combined the power of the twin WM Keck Observatory telescopes atop Mauna Kea in Hawaii.

In the latest study, mature, Sun-like stars were analysed with high precision to search for warm, room-temperature dust in their habitable zones.

The other stars in the study were already known to have significant amounts of distant, cold dust orbiting them.

Many of such stars were found to also have the room-temperature dust.

This is the first time a direct link between the cold and warm dust has been established.

"In other words, if a star is observed to have a cold belt of dust, astronomers now can make an educated guess that its warm habitable zone is also riddled with dust, making it a poor target for imaging exo-Earths," Mennesson said.

The next challenge is to image smaller planets in the "habitable" zone around stars where possible life-bearing "exo-Earths" - Earth-like planets outside the solar system - could reside.

The paper appeared in the Astrophysical Journal.