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In 1995, the scientific magazine Nature published a research
article (Volume 378, page 355) announcing the discovery of the
first extrasolar companion, a giant planet, located around a
"live" star of solar type, named 51 Pegasi. Michel Mayor
and Didier Queloz of the Geneva Observatory made this
historical discovery that was based on radial velocity measurements with
a telescope at the Haute Provence Observatory in France. The reference to a "live star" is made, as opposed to an old
neutron star (or "pulsar") that is at the end of its life. In
fact, the very first extrasolar planet, one of the size of
Earth, was discovered by Alexander Wolszczan in 1991 by means
of extremely accurate radio observations, in orbit around a neutron
star, known as PSR
1257+12. This star rotates at the incredible speed of 161
revolutions per second (the period is 6.21 milliseconds) and is a
pulsar, i.e., a dead star, the extremely compact remains of a sun
bigger than ours that exploded as a huge supernova many millions of
years ago. Geoff Marcy and Paul Butler of San Francisco
University have also discovered many planets around solar type stars
and other astronomers are joining in the hunt. Since 1998, the CORALIE
spectrometer on the Swiss 1.2-m Leonard Euler telescope
at the ESO La Silla Observatory has been
very successful in the search for exoplanets. New results are published regularly on the related websites: |
Last updated July 3, 2001