The Super Earths
01- K-11
02- Migrating Worlds
03- Gliese 581
04- Goldilocks
05- 51 Pegasi
06- Doppler Effect
07- Rhythmic Shift
08- Eccentric Giants
09- Transitters
10- Mu Arae
11- Intermediate World
12- Worlds Observed
13- Extra Solar Earths
14- Migrant Worlds
15- Accretion
16- Core Accretion
17- Disk Erosion
18- Planetary Embryos
19- The Protected Zone
20- Ecosphere
21- Ecosphere II
22- Beta Pictoris
23- Vanquishing Starlight
24- Red Edge / Earth Shine
25- Distant Continents
26- The Age of Stars
   

04 - Goldilocks

Click for enlarged diagram

 

Of more than 200 extra-solar planets so far discovered , or ‘'exoplanets', as scientists call planets found orbiting stars other than our sun, a great many are Jupiter-like gas giants orbiting very close to hot stars. The exoplanet orbiting Gliese 581 is the smallest yet found. It completes a full orbit of its parent star in just 13 days, and it is the most promising yet in terms of harbouring life. It lies in what scientists call the "Goldilocks Zone" where temperatures are just right for life to exist.

It is 14 times closer to its star than the Earth is to our Sun. However, its star is smaller and colder than our Sun and less luminous. So the planet still lies within the "habitable zone", the region around a star where water could exist as liquid.

The Gliese 581 system is now known to have three planets: the new super-Earth, a 15 Earth-mass planet orbiting even closer to the parent star, and an eight Earth-mass planet that lies further out. This is significant in terms of the solar-system formation model outlined later in this section ( see: 'Ecosphere' and 'Ecosphere II' ).

 

GLIESE 581

Mass: Five times Earth's mass
Orbit: 13 days
Temperature: 0C - 40C
Distance: 20.5 light years
Constellation: Libra

 
  Alan Lambert 2011