Why are we surprised?

The theoretical expectations or the prior `common knowledge' (left) are compared with the 1995-1997 observations (right).
What we've ordered: What we've got:
Planetary systems
  • around 1/3(?) of main-seq. stars
  • many planets
  • spaced by a const. factor f=1.5-2.5 (perhaps obeying Titius-Bodes-law)
Dominant giant planets
  • >4% of main-seq. stars
  • single planets (so far)
  • no Saturns in sight (f>>1)
  • disobeying Bode's law
Giant planets
  • not in all planet. sys. (<50%)
  • not much heavier than Jupiter
  • roughly Jupiter's radius
  • Jovian-like composition & structure
Giant "planets"
  • %=?
  • some much more massive than Jupiter
  • radius=?
Familiar orbits
  • in equatorial plane of the star
  • all in prograde motion
  • slightly inclined nearly circular
  • a>5 AU for giants, any distance for terrestrial planets
  • stably configured
Unfamiliar orbits
  • 'Hot' Jupiters - too close
  • Normal Jupiters
  • Eccentric super-Jupiters
  • Pulsar planets - some eccentric