1. DYNAMICAL HABITABILITY IN THE EXTRASOLAR PLANETARY SYSTEMS
47 URSAE MAJORIS AND 55 CANCRI
Siegfried Franck
Christine Bounama
Werner von Bloh
Potsdam Institute for
Climate Impact Research
35th Meeting of the AAS Devision on Dynamical Astronomy
Cannes/ France, April 19-24, 2004

2. HABITABLE ZONES
HZ: range of orbital distances, where the physical conditions at the planet‘s surface are favorable for the existence of life

3. HZ := {R | Π(Patm(R,t), Ts(R,t)) > 0}
HABITABLE ZONES
HZ := {R | Π(Patm(R,t), Ts(R,t)) > 0}

4. THE EXOPLANETARY SYSTEM 47UMa
The Star 47 Ursae Majoris
Spectral Class: G0V
Distance: lightyears
Luminosity: Lsolar ( 0.13)
Mass: Solar Masses
Age: Gyr (+1.2, –1.0)

5. DYNAMICAL HABITABILITY
Jones et al. (2001, 2002, 2003)
MVS (Mixed Variable Symplectic 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

6. 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

7. CONCLUSIONS
Possibility for dynamically habitable Earth-like planets in the systems 47 UMa and 55 Cnc
Higher probability for „water worlds“ of being habitable