Exploration of Ice Giant SystemsWhite Paper sent in response to NASA APIO request

Presentation to OPAG, 11 February 2005Heidi B. Hammel

Space Science Institute

Mark ShowalterSETI Institute

Paul SchenkLunar & Planetary Institute

H. B. Hammel OPAG Open Mike 11 February 2006, Bethesda, MD

Neptune’s Atmosphere1989

Voyager UH 2.2m

1994 1997 20042002

WFPC2

619 nm

H. B. Hammel OPAG Open Mike 11 February 2006, Bethesda, MD

Adaptive Optics Imaging

Keck 10-mMauna Kea

9 July 2004Hammel & de Pater

H (1.6 µm)

AO OFFON

H. B. Hammel OPAG Open Mike 11 February 2006, Bethesda, MD

Uranus at K’ (2.2 µm)2004200320022001

H. B. Hammel OPAG Open Mike 11 February 2006, Bethesda, MD

4th of July “fireworks” in 2004

H

K’

First southern feature ever seen on Uranus >2 µm (including HST NICMOS)

H. B. Hammel OPAG Open Mike 11 February 2006, Bethesda, MD

Uranus Atmosphere as of 2004

• Increasing activity in northern hemisphere– May be development of a northern polar collar

• K’-bright southern feature detected– Evidence for rapid dynamical evolution

• Uranus zonal winds mapped to +48°– Fastest winds yet seen (+229 m/s)

• Equatorial features seen– Global-scale wave pattern

All these results are in press: Hammel et al., Icarus

H. B. Hammel OPAG Open Mike 11 February 2006, Bethesda, MD

Seasonal Change on Uranus

1986 2004

?

Solstice Equinox

Data

fro

m 19

72-1

986

Equinox Solstice