Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tidal evolution of exo-planetary systems: WASP-50, GJ 1214 and CoRoT-7   We perform numerical simulations to investigate tidal evolution of two
single-planet systems, that is, WASP-50 and GJ 1214 and a two-planet system
CoRoT-7. The results of orbital evolution show that tidal decay and
circularization may play a significant role in shaping their final orbits,
which is related to the initial orbital data in the simulations. For GJ 1214
system, different cases of initial eccentricity are also considered as only an
upper limit of its eccentricity (0.27) is shown, and the outcome suggests a
possible maximum initial eccentricity (0.4) in the adopted dynamical model.
Moreover, additional runs with alternative values of dissipation factor
$Q^\prime_1$ are carried out to explore tidal evolution for GJ 1214b, and these
results further indicate that the real $Q^\prime_1$ of GJ 1214b may be much
larger than its typical value, which may reasonably suggest that GJ 1214b bears
a present-day larger eccentricity, undergoing tidal circularization at a slow
rate. For the CoRoT-7 system, tidal forces make two planets migrating towards
their host star as well as producing tidal circularization, and in this process
tidal effects and mutual gravitational interactions are coupled with each
other. Various scenarios of the initial eccentricity of the outer planet have
also been done to investigate final planetary configuration. Tidal decay
arising from stellar tides may still work for each system as the eccentricity
decreases to zero, and this is in association with the remaining lifetime of
each planet used to predict its future.

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The categories of this paper are: hep-ph
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat