London, Sept.29 (ANI): A Cambridge University astronomer has been successful in reworking the distances to over 100,000 stars.

Dr Floor van Leeuwen, who has spent the past 10 years checking and
recalculating data gathered by the Hipparcos satellite,has now
corrected the star distances.

The reworked catalogue (Hipparcos - The New Reduction of the Raw
Data), according to the BBC, will allow astronomers to probe more
deeply into the properties of stars and galaxies.

Astronomers can only determine the physical properties of stars by
comparing their luminosity with their distance from Earth. Without an
accurate measurement of distance, the star's true luminosity or size
cannot be known.

The simple trigonometric parallax method used by Hipparcos to
measure very accurately distances to relatively near objects is a first
stepping stone in the process of inferring the distances to ever-more
remote objects.

The first Hipparcos catalogues were published in 1997, but a debate
then raged because some of the distances listed appeared shorter than
the figures obtained by ground-based observations.

Dr van Leeuwen identified a systematic flaw resulting from
temperature fluctuations experienced by Hipparcos as it moved around
the Earth. This made the spacecraft twist slightly and skew some of its
data.

"It was an extremely painful process. You can spend a whole weekend
examining one small part of the data, and making the resultant
corrections can take two weeks. But the result is that we now have a
catalogue more accurate than ever before, and one in which we know that
all the calculations work," Dr. Leeuwen says.

The European Space Agency will launch the Gaia spacecraft early in
the next decade. It will compile a catalogue of vastly more stars at
even greater distances.

The new Hipparcos data is published by Springer as Volume 350 in the Astrophysics and Space Science Library Series. (ANI)