types of extra-solar planets & how they got to be that way

march 2003

the extrasolar planets catalog

the known stars with exoplanets are distributed in distance from their star as such

the distribution of planets' masses is here


surprise result:  at the jupiter-mass level, more planets of smaller mass
(contrary to expectations due to selection effects)

the distribution of planets' eccentricities is here

classification of planetary systems (Mar ‘03)
properties of extrasolar planets
planetary class
single planet 
systems (79)
all planets
hot Jupiters
in circular orbits
a <  0.25 au
T > 500 K
cool Jupiters 
in circular orbits
(planets like ours?)
4 au > a > 1.0 au
130 K < T < 250 K
eccentric orbits
e > 0.1

why hot Jupiters were unexpected

why are the hot Jupiters so close to their stars?
(19/105 planets have d < 0.25 au)

the majority view

the minority view
why didn't Jupiter migrate in?

(or why aren't all giant planets close to their stars?)

why circular orbits were expected

so what about the eccentric-orbit planets?
(59/105 have e >  0.3; 81/105 have e > 0.1)

so what are hot Jupiters made of?

  •  HD 209458b, the only extrasolar planet with a known atmosphere has a hot hydrogen atmosphere evaporating from the planet

  • planet supported by electron degeneracy;  RP a MP1/3  but strongly influenced by

  • the extent to which it has already contracted when it reached its present orbit and/or the presence/absence of a rocky core
    extrasolar planet summary