![Page 1: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/1.jpg)
New Moons Around Pluto
Jau-Shian LiangDepartment of Physics, NTHU
2005/11/24
![Page 2: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/2.jpg)
Introduction
• H. A. Weaver (Applied Physics Laboratory, Johns Hopkins University) and S. A. Stern (Southwest Research Institute) report the discovery of two new satellites of Pluto.
• The new satellites were detected using the images obtained by Hubble Space Telescope in May, 2005
![Page 3: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/3.jpg)
Pluto and Charon• Average distance from Sun: 39.53AU• Revolution period: 248.54 years• Rotation Period: 6.3872 days 6.3872days• Radius: 1150-1215km 600-640km• Density: ~2g/cm3 1-2g/cm3
• Brightness: 13.6 magnitude 15.5mag• Geometric albedo: 0.55,variable 0.35• Color(V-I): 0.93magnitude 0.83mag• Known surface ices: CH4, N2, CO, ? H2O, ?• Atmosphere: confirmed ?• Date of discovery: 1930 1978
![Page 4: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/4.jpg)
Observation
• Mission: Hubble Space Telescope• Instrument: ACS/WFC ACS/HRC• Filters: F606W (V) F475W (B), F555W
(V)• Date: May 15/18, 2005 various dates
in 2002 and 2003
![Page 5: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/5.jpg)
(288 sec) (3800 sec) (3800 sec)
![Page 6: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/6.jpg)
S/2005 P1 V= 22.96 +/- 0.15S/2005 P2 V= 23.41 +/- 0.15S/N > 35
S/2005 P1
S/2005 P2 S/2005 P2
S/2005 P1
![Page 7: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/7.jpg)
Orbit
• Unique orbits cannot be calculated from only two Hubble measurements.
• The measured positions are consistent with nearly circular orbits in the orbital plane of Pluto I (Charon).
![Page 8: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/8.jpg)
•S/2005 P 1
a = 64’700 ± 850 km
P = 38.2 ± 0.8 days
•S/2005 P 2
a = 49’400 ± 600 km
P = 25.5 ± 0.5 days
![Page 9: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/9.jpg)
A re-examination of older Hubble images
![Page 10: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/10.jpg)
Approximate Diameter
Assumed Reflectivity Approximate Diameter 4% (like the darkest known KBOs) 160 km 15% (like many KBOs) 80 km 35% (like Charon) 52 km
![Page 11: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/11.jpg)
• The team plans to make follow-up Hubble observations in February to confirm that the newly discovered objects are truly Pluto's moons.
• If confirmed, the discovery of the two new moons could offer insights into the nature and evolution of the Pluto system, Kuiper Belt Objects with satellite systems, and the early Kuiper Belt.
![Page 12: New Moons Around Pluto Jau-Shian Liang Department of Physics, NTHU 2005/11/24](https://reader030.vdocument.in/reader030/viewer/2022032800/56649d4d5503460f94a2c679/html5/thumbnails/12.jpg)
Reference• http://hubblesite.org/newscenter/newsdesk
/archive/releases/2005/19/• http://www.boulder.swri.edu/plutonews/