occultation by charon
DESCRIPTION
Occultation by Charon. 2005 C313.2. Observed by 4 MIT–Williams teams on 5 telescopes: Pico dos Dias (Brazil) – clouded out (Jay Pasachoff and Steven Souza) Cerro Armazones (Chile) (Bryce Babcock and Joseph Gangestad) Las Campanas (Chile) Cerro Pachón (Chile). - PowerPoint PPT PresentationTRANSCRIPT
Occultation by Charon2005
C313.2
• Observed by 4 MIT–Williams teams on 5 telescopes:
• Pico dos Dias (Brazil) – clouded out (Jay Pasachoff and Steven Souza)
• Cerro Armazones (Chile)(Bryce Babcock and Joseph
Gangestad)• Las Campanas (Chile)• Cerro Pachón (Chile)Movie of C313.2 from Las Campanas-
http://occult.mit.edu/research/C313OccMovie.php
Cerro Armazones, Chile(L to R) M. J. Person, B. A. Babcock, & J. W. Gangestad
Pico dos Dias, BrazilS. P. Souza (L), J. M. Pasachoff (R)
Where we were …
… and the parts of Charon we saw
Cerro Armazones Light Curve
Duration: 37 secMid-time: 03:36:36.5 UT
Sharp drop No atmosphere detected
Team Light CurvesClay Telescope (6.5 m),Las Campanas
Gemini South (8 m)Cerro Pachón
Cerro Armazones (0;.84 m),Antofagasta, Chile
Du Pont Telescope (2.5 m),Las Campanas
0.85-m
6.5-m 2.5-m
8-m
Upper Limits on Charon’s Atmosphere
Gas Molecular Weight (amu) Number density (1013 cm-3)CH4 16.04 2.0H2O 18.02 3.4Ne 20.18 11.9N2 28.01 2.3Ar 39.95 2.0
Clay Telescope data
Gulbis, A.A.S., Elliot, J.L., Person, M.J., Adams, E.R., Babcock, B.A., Emilio, M., Gangestad, J.W., Kern, S.D., Kramer, E.A., Osip, D.J., Pasachoff J.M., Souza, S.P., Tuvikene, T. “Charon’s radius and atmospheric constraints from stellar occultation observations” Nature, in press
Seconds after reference time
Radius and Composition Constraints
Radius: 606 ± 8 km
Density: 1.72 ± 0.15 g/cm3
Rock/Ice: 0.63 ± 0.05
This rock/ice fraction is consistent with a collisional formation scenario.
http://ncsdweb.ncsd.k12.wy.us/planetarium/ART/moonimpact.jpg