The Age of What comets tell us about the the early ! Carsten Dominik University of Amsterdam Radboud University Nijmegen The mission to 67P/Churyumov-Gerasimenko

2004

2014

Image credits: ESA/ESO Bernard 68: ready for collapse

Image credit: ESO Collapse and Rotation Real disks What are comets?

• Small solar system body • Very hard to detect when far from • Develop and tails when close to Sun Comet outgassing

Image: ESA Comet coma

Image credit: Vicent Peris and José Luis Lamadrid Comet tails Comet tails

Gas small grains

larger grains Key properties of comets

• Size • Strength • Composition • Orbital properties Temple 1 7.6 km Size

Hartley 2.25 km

Wild 2 5.5 km Formation

Agglomeration ~1 µm ~1 km ~10000 km

Preplanetary dust Strength Comet SL9 1994 Tidal breakup Breakup to equal blocks requires very weak material Composition

Mumma & Charnley 2011

• Dust (Silicates and Carbonaceous) • Ices H2O, CO, CO2, HCN, CH3CN, CS….. Amorphous Olivine

Amorphous Pyroxene

Crystalline Forsterite

Crystalline Enstatite

Silica

PAH Comparison comet Hale-Bopp versus disk HD 100546

Malfait et al 1998 Deuterium in Comets Comet orbits

Kay Gibson, Ball Aerospace & Technologies Corp Where comets come from, part I Öpik 1932, Oort 1950 Creating the

Circular orbits

Far away

Eccentric,! reaching to planets Comet orbits

Kay Gibson, Ball Aerospace & Technologies Corp (1930)

ClydeClyde TombaughTombaugh Orbit of Pluto 1992 QB1 ... en Kuipergordel objecten

Orbit of

Orbit of

29-09-2009 LWSK 29 Origin of comet reservoirs

Brett Gladmann Science 2005

Distribution of orbital elements Pluto’s resonant capture Pluto’s resonant capture Pluto’s resonant capture

a

Neptune P t=0 time e today time 1:1 3:2 2:1 i

time The age of comets (Wag the dog)

Credit: Sky & Telescope The End

• Comets are first class witnesses of the formation and early evolution of the solar system • Together with observations of planets and of protoplanetary disks, they can indeed be a Rosetta Stone for understanding our origins