Theia's date with destiny: possible conditions leading to a Giant Impact...
Δημοσιεύτηκε στις 13 Ιαν 2015
Billy Quarles
NASA Ames
The
Giant Impact theory is the leading explanation for the Moon's origin,
but mysteries remain in the conditions leading up to the event.
Collisions were common during the turbulent infancy of the Solar System
and led to a small set of terrestrial planets.
Dr. Quarles
presents a numerical model that considers the penultimate orbits of the
Solar System, when five terrestrial planets are present. From this
model, he indicates which starting parameters for Theia (the proto-Moon)
result in a late Giant Impact consistent with physical dating
constraints.
He also finds that the likely semimajor axis of
Theia, at the epoch when the simulations begin, depends on the assumed
mass ratio of the Earth-Moon progenitors (8/1, 4/1, or 1/1). The low
eccentricities of the resulting terrestrial planets are most commonly
produced when the progenitors have similar semimajor axes at the epoch
when the model starts.
Additionally, Dr. Quarles will show that
perturbations from the giant planets can affect the dynamical evolution
of the system leading to a late Moon Forming Giant Impact.
NASA Ames
The
Giant Impact theory is the leading explanation for the Moon's origin,
but mysteries remain in the conditions leading up to the event.
Collisions were common during the turbulent infancy of the Solar System
and led to a small set of terrestrial planets.
Dr. Quarles
presents a numerical model that considers the penultimate orbits of the
Solar System, when five terrestrial planets are present. From this
model, he indicates which starting parameters for Theia (the proto-Moon)
result in a late Giant Impact consistent with physical dating
constraints.
He also finds that the likely semimajor axis of
Theia, at the epoch when the simulations begin, depends on the assumed
mass ratio of the Earth-Moon progenitors (8/1, 4/1, or 1/1). The low
eccentricities of the resulting terrestrial planets are most commonly
produced when the progenitors have similar semimajor axes at the epoch
when the model starts.
Additionally, Dr. Quarles will show that
perturbations from the giant planets can affect the dynamical evolution
of the system leading to a late Moon Forming Giant Impact.
Κατηγορία
Άδεια
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