ExtraSolar Planets: New Clues for Planet Formation
William Cochran (Texas)
Approximately 100 planetary-mass companions to solar type stars have
been discovered using high precision radial velocity techniques.
Recent discoveries include planets with minimum masses below that of
Saturn, many systems with indications of multiple planets, and a
jovian-mass companion to one of the nearest stars to the sun,
epsilon Eridani. This talk will review the present status of
extrasolar planetary systems. The distribution of masses and orbital
properties offers interesting clues to the origin and evolution of
these systems. The apparent tendency of extrasolar planets to
be found preferentially around stars of high heavy element abundance will
be examined. The very severe selection effects in the radial
velocity discoveries will be discussed. The past years has also
seen the emergence of a new technique for study of extra-solar
planets in the form of high precision photometry of planetary
transits across the disk of the parent star. We will summarize
many of the recent results in transits in the HD209458 system and
in the globular cluster 47 Tuc. The near-term future offers many
exciting prospects for new types of planet discoveries. We will
briefly discuss these prospects, and the added information that
they will offer on the origin and evolution of extrasolar planetary
systems.
