McKagan S.,University of Colorado and NIST
Physics Teacher | Year: 2010
This article describes workshops for high school physics teachers in Uganda on inquiry-based teaching and PhET simulations. I hope it increases awareness of the conditions teachers face in developing countries and inspires others to give similar workshops. This work demonstrates what is possible with some concerted, but not extraordinary, effort. © 2010 American Association of Physics Teachers.
Flaherty K.M.,Wesleyan University |
Hughes A.M.,Wesleyan University |
Rosenfeld K.A.,Harvard - Smithsonian Center for Astrophysics |
Andrews S.M.,Harvard - Smithsonian Center for Astrophysics |
And 5 more authors.
Astrophysical Journal | Year: 2015
Turbulence can transport angular momentum in protoplanetary disks and influence the growth and evolution of planets. With spatially and spectrally resolved molecular emission line measurements provided by (sub)millimeter interferometric observations, it is possible to directly measure non-thermal motions in the disk gas that can be attributed to this turbulence. We report a new constraint on the turbulence in the disk around HD 163296, a nearby young A star, determined from Atacama Large Millimeter/submillimeter Array Science Verification observations of four CO emission lines (the CO(3-2), CO(2-1), 13CO(2-1), and C18O(2-1) transitions). The different optical depths for these lines permit probes of non-thermal line-widths at a range of physical conditions (temperature and density) and depths into the disk interior. We derive stringent limits on the non-thermal motions in the upper layers of the outer disk such that any contribution to the line-widths from turbulence is <3% of the local sound speed. These limits are approximately an order of magnitude lower than theoretical predictions for full-blown magnetohydrodynamic turbulence driven by the magnetorotational instability, potentially suggesting that this mechanism is less efficient in the outer (R 30 AU) disk than has been previously considered. © 2015. The American Astronomical Society. All rights reserved.