July 26, 2006

Fiber Optic array for finding Kuiper belt objects

Fiber optic telescope array used to look for Kuiper belt objects. There might be 5 to 10 times the 100 billion object estimate. The researchers looked for split-second 'winking', or darkening, of stars which suggests a Kuiper belt object is passing in front, or occulting the star. They found evidence of many objects ranging in size from 300 metres to one kilometre across using a 6DF instrument on the UK Schmidt telescope at Siding Spring.

The 6DF, which uses fibre optics, monitored 100 stars simultaneously over two weeks, the equivalent of 7000 star hours, or watching a single star every night for 3 years.

"We've got 100 fibres, each one of which is positioned on a star and then we feed the fibres into a high speed camera," he says. They saw at least 100 very definite occultations and 1000 less significant events.

The Kuiper belt community has greeted the news with some scepticsm. Some critics say that the apparent dimming of the stars may be due to effects in the Earth's atmosphere. About 1000 large bodies, including Pluto and the recently discovered Xena, have been located in the Kuiper belt so far. Smaller objects have evaded detection as they are about 15 billion kilometres from the Sun, making it impossible to see them even with a powerful instrument like the Hubble Space Telescope.

Ashley says the scientists took pains to rule out other possible causes for dips in stars, including moths in the telescope.