AAS Cannes 2004, April 19-24

DYNAMICAL HABITABILITY IN THEEXTRASOLAR PLANETARY SYSTEMS47 URSAE MAJORIS AND 55 CANCRI

Siegfried FranckChristine BounamaWerner von Bloh

Potsdam Institute forClimate Impact Research

35th Meeting of the AAS Devision on Dynamical Astronomy

Cannes/ France, April 19-24, 2004

AAS Cannes 2004, April 19-24

HABITABLE ZONES

HZ: range of orbital distances, where the physical conditions at the planet‘s surface are favorable

for the existence of life

AAS Cannes 2004, April 19-24

HABITABLE ZONES

HZ := {R | Π(Patm(R,t), Ts(R,t)) > 0}

AAS Cannes 2004, April 19-24

THE EXOPLANETARY SYSTEM 47UMa

The Star 47 Ursae Majoris

Spectral Class: G0VDistance: 45 lightyearsLuminosity: 1.54 Lsolar ( 0.13) Mass: 1.03 Solar MassesAge: 6.3 Gyr (+1.2, –1.0)

AAS Cannes 2004, April 19-24

DYNAMICAL HABITABILITY

Jones et al. (2001, 2002, 2003)MVS (Mixed Variable SSymplectic Integration Method)eccentricity small (inside HZ); R outside 3 RHill

Rout ~ 1.32 AU

Noble et al. (2002) Gozdziewski (2002)Rout ~ 1.25 AU MEGNO (Mean Exponential Growth

Factor of Nearby Orbits)Rout ~ 1.30 AU

AAS Cannes 2004, April 19-24

RESULTS FOR 47UMa

Cuntz, M., von Bloh, W., Bounama, C., Franck, S., Icarus 162, 214, 2003

Franck, S., Cuntz, M., von Bloh, W., Bounama, C., Int. J. Astrobiology 2(1), 35, 2003

AAS Cannes 2004, April 19-24

CONCLUSIONS

• Possibility for dynamically habitable Earth-like planets in the systems 47 UMa and 55 Cnc

• Higher probability for „water worlds“ of

being habitable

www.pik-potsdam.de/PLACES