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