Friday, April 17, 2009
(Note: Special place)
Syzygies: Eclipses, Occultations, and Transits
Williams College and Caltech
I report on observations of three series of events, all of which depend on precise alignments of astronomical objects and which requre observations at specific times. At total solar eclipses, most recently 1 August 2008 in Siberia, we searched for coronal oscillations through narrow-band filters for coronal visible-light emission lines as a distinguishing characteristic among theories of the heating of the corona to millions of degrees. The eclipse work also provides high-resolution coronal imaging through new data-processing methods as well as the extension of coronal streamers and plumes observed from solar spacecraft into spatial regions unobservable at space with present satellite capabilities. The occultation work has in recent years centered on Pluto and Charon, and which we are working to extend to objects further out in the solar system. We have found Pluto's atmosphere to be warming even as far as we are past perihelion, and we have placed strict limits on Charon's atmosphere. We have, further, applied our observational abilities to the 2004 transit of Venus and the 2006 transit of Mercury, and we have used spacecraft observations of the total solar irradiance to provide well-understood analogs of exoplanet transits.
Refreshments at 4:00 PM. Seminar begins at 4:10 PM.
Building 3, Room 2137
For further information, please call (909) 869-4014