Europlanet 2007, Potsdam, Highlights

http://meetings.copernicus.org/epsc2007/

Exoplanets• Corot

– Fridlund (abstract 474) - summary of mission. So far, short sequence on one field (60 day). Many candidates. 1st papers due in 5-6 months. Mass function continues to small masses.

– Barge et al. (316) - So far, 1 planet + 18 candidates.

• Microlensing– Beaulieu et al. (440) - PLANET project. 1 more Jupiter this season.

• Radio emissions– Griessmeier et al. (395) - Hot Jupiters have strong interactions with

stellar winds, should be visible at low frequency radio (10-25 Mhz). Not yet, but new Ukrainian T-shape Radio telescope should do it.

• Spin up of stars– Carone & Paetzold (386) - Tides from Hot Jupiters can spin up star.

Planet formation

• Abundances of gas/solids in disks– Davis (086) - snow line can be as close as 1.7 AU, water ice in inner disk.

CO ice + gas at ~50 AU.

• Collision experiments– Wurm et al. (309) - using a cross bow! - dust aggregates < 10cm. For solid

targets, fast collision needed to add mass. For dust target, only smaller particles accrete.

– Heibbelmann et al. (194) - 5% kinetic energy conserved - deformation/compaction of aggregates.

• Rubble pile structure– Bagatin (505) - Rubble piles are most likely a large solid centre and small

particles around it, not full collection of small particles.

Planet formation

• Early Solar System geochemistry– Quitte (437) - Age of Iron meteorites shows that either they are not from

differentiated bodies, or differentiation happened early (4Ma). Fe60 from meteorites shows that there must have been a supernova in the vicinity of the Sun a few 100k years before Solar System formation.

• Differentiation models– Castillo-Rogez & McCord (466) - Ceres models suggest a possible sub-

surface ocean today.– Ziethe et al. (034) - Depending on assumed parameters, original size for

differentiation is 500 - 1000 km radius. Smaller if heating (eg radioactive decay) included. Small bodies differentiate eventually if they avoid collisions.

• Dynamics– Horner & Jones (059) - Jupiter’s influence on the collision rate at Earth - if

smaller Jupiter, more JFC impacts. But if it didn’t exist, less impacts as few JFCs enter inner Solar System.

TNOs/KBOs

• Density & structure– Brown (293) - general trend of increasing density with size -

abnormally high density of 2003 EL61 can be explained as it being remnant core of differentiated body smashed by collision. Collisional family contains many smaller bodies which are close to pure water ice - ie surface layers of differentiated body.

– Hussmann & Sohl (480) - models suggest that nearly all larger KBOs can have oceans below ice surfaces.

• Surfaces– Alvarez-Candal et al. (214) - SINFONI spectra of TNOs show water

absorption bands and possible rotational variation.– Pinilla-Alonso et al. (252) - There is a carbon depleted population in

TNOs - fits with carbon depleted comets.

Comets

• Spacecraft results– Burchell et al. (268) - Stardust - varied D/H ratio, range of mineralogy but no

hydrous materials. Organics present. Clusters of small particles - dust splitting.

– Kossacki & Szutowicz (079) - 9P/Temple 1 dust - dust comes from subsurface as surface is old with little exposed ice. Dust mantle mostly thick with low thermal inertia, in places thin though.

• JFC observations– Tubiana et al (041) - 67P/Churyumov-Gerasimenko - Many observations,

May 2006 - Mar 2008, size, shape, rotation, colours, phase function. All typical.

– Lara et al. (044) - Fragmenting comet 73P/Schwassman-Wachmann 3 - fragments continued to behave as small comets. Some fragmented further.

– Snodgrass et al (123) - General properties of JFCs.

Comets

• Main Belt comets– Licandro et al. (284) - not comets - hydrated materials, but no ices - activity

gas driven, not from sublimating ice. Searching for CN gas.

• Dust– Jian et al (149) - Solar wind interaction with dust streams - ICME interacts

with dust, change in magnetic field direction. Observed in measurements downstream of McNaught tails. Model needed.

– Lasue et al. (198) - Dust is fluffy and organic (polarimetry - Hale-Bopp & in situ - Stardust) - Simulation of aggregation gives nucleus with cohesive core and low cohesion outer layers. Craters removed by activity model.