Creating Gateway Alliances Using WS-PGRADE/gUSE - Science Gateways for Distributed Computing Infrastructures - page 255

18.4.4 Dynamical Evolution of Small Bodies in the Solar
System

This research focuses on finding the answers of two open questions related to

dynamics of small bodies in our planetary system. In particular, it studies the
trajectories of interstellar comets passing through the outer Solar System and also
the evolution of meteoroid streams, including the study of dynamical properties of
their parent bodies.

18.4.4.1 Interstellar Comets

The trajectories of interstellar comets passing the Solar System are gravitationally
influenced by the galactic tide. A combination of this influence and gravity of the
Sun can change the trajectories in the way that the comets become bound to the
solar system, i.e., they become a part of the comet Oort cloud. For the current
position of the Sun in the galaxy and considering its relatively high peculiar
velocity, the intervals of the comet orbital phase space, where the “ capture

happens , occur to be extremely narrow. In addition, a preliminary analysis of the

problem revealed that the problem is nonlinear. So, the appropriate

”

“ capture win-

dow can appear for an unexpected combination of comet orbital parameters (one

cannot simply look for a mathematical local minimum).
The COMCAPT (COMets CAPTure) application calculates the critical param-
eters of the capture for a huge number of interstellarcomet trajectories (on the order
of magnitude equal to 1012) and evaluates if the condition of the capture is satis

”

ed
for the given combination of 4-D orbital characteristics or not. The application is
expected to be rerun for various combinations of two input values, i.e. the distance
of the Sun from the Galactic center and the magnitude of the peculiar velocity of the
Sun with respect to the Local Standard of Rest.
The workflow (Fig. 18.5 ) is designed to run on a gLite grid infrastructure. First,
the input data is copied to the storage element (SE). Then, a management routine is
run to split the individual subtasks from the SE on the individual computing ele-
ments (CEs), depending on the number of available CPUs in the grid to calculate
the critical parameters of the captures for a given subperiod and move the output
results back to the SE. Finally, the resulting data of the computation is collected and
downloaded. For this reason, the parameter sweep capabilities of the gUSE
workflow interpreter are employed. The

node is a generator that provides
inputs for COMCAPT, which is executed in as many job instances as inputs
generated, and calculates some critical parameters. Based on these parameters,
COMCAPT evaluates if the expected capture of interstellar comets into the comet
Oort cloud happens for a given combination of subinput data. Figure 18.5 shows an
example of the trajectory of theoretical comet on the projection to the x

“ split ”

y coor-

-

dinate plane of quasibound orbit around the Sun located at (0, 0).