<div dir="ltr">CfA SSP talk <a href="http://www.cfa.harvard.edu/events/calendar/latest.html">http://www.cfa.harvard.edu/events/calendar/latest.html</a><br>
<br> MONDAY, SEPTEMBER 29<br>
<br>
12 noon: [22]Solar, Stellar, and Planetary Sciences Division Seminar.<br>
"On the Origin of Planetary Spins & the Formation of Kuiper Belt<br>
Binaries," Dr. Hilke Schlichting, California Institute of Technology.<br>
Pratt Conference Room.<br>
<br>
Abstract: The accretion of planetesimals is usually treated as<br>
collisionless. The assumption is that collisions among the<br>
planetesimals can be neglected while they are within the proto-planets<br>
sphere of gravitational influence. In the first part of my talk, I<br>
will show that if planetesimals are of order of a meter in size or<br>
smaller, then they are likely to collide within the proto-planet's<br>
sphere of gravitational influence (semi-collisional accretion),<br>
creating a prograde accretion disk around the proto-planet. Accounting<br>
for the subsequent stages in terrestrial planet formation, this<br>
semi-collisional accretion biases the final spin of terrestrial<br>
planets toward prograde rotation. I will suggest that in our Solar<br>
system, semi-collisional accretion gave rise to the preference for<br>
prograde rotation observed in the terrestrial planets and perhaps the<br>
largest asteroids. The second part of my talk will be concerned with<br>
the binaries in the Kuiper belt. I will discuss the various proposed<br>
binary formation scenarios and highlight which mechanism will dominate<br>
the binary formation for a given velocity regime. Finally, I will show<br>
that the sense of the binary orbit provides a powerful tool for<br>
discriminating between the different binary formation scenarios<br>
observationally.<br clear="all"><br>-- <br>Sarah T. Stewart-Mukhopadhyay<br>Asst. Professor of Planetary Science<br>Dept. of Earth & Planetary Sciences, Harvard University<br>Office 617.496.6462 Lab 617.496.5782 Fax 617.384.8249<br>
<a href="mailto:sstewart@eps.harvard.edu">sstewart@eps.harvard.edu</a><br><a href="http://www.fas.harvard.edu/~planets/sstewart/">http://www.fas.harvard.edu/~planets/sstewart/</a><br><br>Assistant:Marcie Steeves, <a href="mailto:steeves@eps.harvard.edu">steeves@eps.harvard.edu</a>, 617-495-2350<br>
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