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Cover PageStar ChartPhotographRadial VelocityHabitable ZoneOrbitsSystem DataPlanetary Life?Further Info

Over 20 light-years away,Earth-like planets?

Credit: ESO


LocationR.A.: 15h19m26sDec: -07d43’20”


Image ca. 20 arc minutes wide. Credit: DSS


Credit: ESO


Credit: ESO


Orbits


Constellation: LibraSpectrum: M3Age vs Sun: nearly 2xDistance: 20.4 lyMagnitude: 10.6 mvSun masses: 0.31Sun radii: 0.38Sun luminosity: 0.00202Temperature: 3,250oKSun magnitude: 3.81 mv

Earth masses: 15.65Distance: 0.04AUPeriod: 5.37 dEccentricity: 0

Earth masses: 5.36Distance: 0.07AUPeriod: 12.93 dEccentricity: 0.17

Earth masses: 7.09Distance: 0.22AUPeriod: 66.8 dEccentricity: 0.38

b

c

d

Star cataloged as Gliese 581

1AU = 149.598 mio km (93.5 mio miles)

System Data

Earth masses: 1.94Distance: 0.03AUPeriod: 3.15 dEccentricity: 0

e


Is Life out there on ‘c’ and ‘d’?Pros:• Super-Earth-class size• Situated in Gliese 581’s HZ• Existence of liquid water possible• Grainy or ocean covered surface

Cons:• Radiation impact from the star• Probably tidally locked

Anyway:The system is “only” 20.4 light-years away and therefore a travel target for the future by when

our successors will know more about this planetary system, which may count more than

the four planets known to date. Suppose it would be possible to travel near the speed

of light, the journey would take about 6.1 years one-way at 1g acceleration.

Credit: ESO


Further information:

The Crowded Universe by Alan Boss on Fora TV

http://fora.tv/2009/03/13/Alan_Boss_The_Crowded_Universe

The Extrasolar Planet Encyclopaedia

http://exoplanet.eu

Planetquest

http://planetquest.jpl.nasa.gov

The Kepler Mission

http://kepler.nasa.gov

http://fora.tv/2009/03/13/Alan_Boss_The_Crowded_Universe

http://exoplanet.eu/

http://planetquest.jpl.nasa.gov/

http://kepler.nasa.gov/