We explore the origin
and orbit
al evolution of the Kuiper belt in the fr
amework of
a recent model of the dyn
amic
al evolution of the gi
ant pl
anets, sometimes known
as the
Nice model. This model is ch
ar
acterized by
a short, but violent, inst
ability ph
ase, during which the pl
anets were on l
arge eccentricity orbits. It successfully expl
ains, for the first time, the current orbit
al
architecture of the gi
ant pl
anets [Tsig
anis, K.,
Gomes, R., Morbidelli, A., Levison, H.F., 2005. N
ature 435, 459–461], the existence of the Troj
ans popul
ations of Jupiter
and Neptune [Morbidelli, A., Levison, H.F., Tsig
anis, K., Gomes, R., 2005. N
ature 435, 462–465],
and the origin of the l
ate he
avy bomb
ardment of the terrestri
al pl
anets [Gomes, R., Levison, H.F., Tsig
anis, K., Morbidelli, A., 2005. N
ature 435, 466–469]. One ch
ar
acteristic of this model is th
at the proto-pl
anet
ary disk must h
ave been trunc
ated
at roughly 30 to <
a n
ame=""mml1"">
a><
a style=""text-decor
ation:none; color:bl
ack"" href=""/science?_ob=M
athURL&_method=retrieve&_udi=B6WGF-4S6G92F-1&_m
athId=mml1&_user=1067359&_cdi=6821&_rdoc=21&_
acct=C000050221&_version=1&_userid=10&md5=4b70b03f8d31d94b
afe063e584d5e368"" title=""Click to view the M
athML source""
alt=""Click to view the M
athML source"">35
a0;AU
a> so th
at Neptune would stop migr
ating
at its currently observed loc
ation. As
a result, the Kuiper belt would h
ave initi
ally been empty. In this p
aper we present
a new dyn
amic
al mech
anism which c
an deliver objects from the region interior to <
a n
ame=""mml2"">
a><
a style=""text-decor
ation:none; color:bl
ack"" href=""/science?_ob=M
athURL&_method=retrieve&_udi=B6WGF-4S6G92F-1&_m
athId=mml2&_user=1067359&_cdi=6821&_rdoc=21&_
acct=C000050221&_version=1&_userid=10&md5=edc51e40ee734739b1
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athML source""
alt=""Click to view the M
athML source"">
alt=""not, vert, simil
ar"" title=""not, vert, simil
ar"" border=""0"">35
a0;AU
a> to the Kuiper belt without excessive inclin
ation excit
ation. In p
articul
ar, we show th
at during the ph
ase when Neptune's eccentricity is l
arge, the region interior to its 1:2 me
an motion reson
ance becomes unst
able
and disk p
articles c
an diffuse into this
are
a. In
addition, we perform numeric
al simul
ations where the pl
anets
are forced to evolve using fictitious
an
alytic forces, in
a w
ay consistent with the direct
N-body simul
ations of the Nice model. Assuming th
at the l
ast encounter with Ur
anus delivered Neptune onto
a low-inclin
ation orbit with
a semi-m
ajor
axis of <
a n
ame=""mml3"">
a><
a style=""text-decor
ation:none; color:bl
ack"" href=""/science?_ob=M
athURL&_method=retrieve&_udi=B6WGF-4S6G92F-1&_m
athId=mml3&_user=1067359&_cdi=6821&_rdoc=21&_
acct=C000050221&_version=1&_userid=10&md5=dd0
a0965f
aa0d9076f3582fb3d14f1fe"" title=""Click to view the M
athML source""
alt=""Click to view the M
athML source"">
alt=""not, vert, simil
ar"" title=""not, vert, simil
ar"" border=""0"">27
a0;AU
a>
and
an eccentricity of
alt=""not, vert, simil
ar"" title=""not, vert, simil
ar"" border=""0"">0.3,
and th
at subsequently Neptune's eccentricity d
amped in
alt=""not, vert, simil
ar"" title=""not, vert, simil
ar"" border=""0"">1 My, our simul
ations reproduce the m
ain observed properties of the Kuiper belt
at
an unprecedented level. In p
articul
ar, our results expl
ain,
at le
ast qu
alit
atively: (1) the co-existence of reson
ant
and non-reson
ant popul
ations, (2) the eccentricity–inclin
ation distribution of the Plutinos, (3) the peculi
ar semi-m
ajor
axis—eccentricity distribution in the cl
assic
al belt, (4) the outer edge
at the 1:2 me
an motion reson
ance with Neptune, (5) the bi-mod
al inclin
ation distribution of the cl
assic
al popul
ation, (6) the correl
ations between inclin
ation
and physic
al properties in the cl
assic
al Kuiper belt,
and (7) the existence of the so-c
alled extended sc
attered disk. Nevertheless, we observe in the simul
ations
a deficit of ne
arly-circul
ar objects in the cl
assic
al Kuiper belt.