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The Transient Universe: AY 250 Spring 2007
Near Earth Asteroidsand Kuiper Belt Objects
Geoff Bower
The Transient Universe: AY 250 Spring 2007 Jewitt 2000
The Transient Universe: AY 250 Spring 2007
Tunguska
50 km diameter
The Transient Universe: AY 250 Spring 2007
Fatalities
The Transient Universe: AY 250 Spring 2007
Estimates of Impact Rate
• Lunar cratering– D ~ E^1/3.5– D ~ 3 – 100 km– N(D) ~ D^-1.7– Survey back to 3 Gyr
• One 10 km impact/10^8 y
• Telescopic surveys
The Transient Universe: AY 250 Spring 2007
The Transient Universe: AY 250 Spring 2007
The Transient Universe: AY 250 Spring 2007
The Transient Universe: AY 250 Spring 2007
The Transient Universe: AY 250 Spring 2007
NEA Search Requirements
• Depth– For small, distant objects
• Large FOV– For completeness
• High resolution
• Cadence– For accurate orbits
• Rapid data reduction
The Transient Universe: AY 250 Spring 2007
Sedna Discovery
Brown et al 20044.6”/3.1 hourR=20.5
Palomar Oschin telescope
The Transient Universe: AY 250 Spring 2007
Inner Oort Cloud Object
SednaBrown et al 2004
76 – 480 AU
The Transient Universe: AY 250 Spring 2007
Eris/UB313The Largest Dwarf Planet
1.4”/hrBrown et al 2005R=18 mag 2400 +/ 100 km diameter
96 AU
The Transient Universe: AY 250 Spring 2007
KBO Distribution
The Transient Universe: AY 250 Spring 2007
KBO Variability
Sheppard & Jewitt
6.7 hour period
The Transient Universe: AY 250 Spring 2007
Colors of KBOs
Jewitt & Luu 2001
The Transient Universe: AY 250 Spring 2007
The Predictions for P* and LSST
• 10 km size threshold
• ~10 objects w/size 1000 km
• N (> size) ~ size^-3 10^7 new objects
discovered
• 1 km size threshold
10^10 new objects
The Transient Universe: AY 250 Spring 2007
Transient/Rock Confusion
• Pan Starrs
• 10^7 objects• 5 y / 10 sec
integrations ~ 10^7 observations
• 1 object/observation
• LSST
• 10^10 objects
1000 objects/observation
The Transient Universe: AY 250 Spring 2007
Transient/Rock Confusion II
• Proper motion
• Inclination to ecliptic
• Catalog
• Color
• Multi-wavelength activity
• Universal cadence