Gliese 876 - (Local Group)

Gliese 876 is a small Red Dwarf star, that is only 15.3 Light Years (4.7 Parsecs) away from our own solar system.  Being within the 5 Parsec limit, this makes this star a member of our Local Group of stars.  However this star is so small and dim that it cannot be seen with the naked eye.  It's only about 2% the brightness of out star.  It is the closest star so far that not only has a planet, but three of then, one huge earth sized planet and 2 Jupiter sized planets both of which are in the stars Habitable Zone!

 Added: 09/23/2006

Artwork of a Red Dwarf star, courtesy of NASA/GSFC.


Rendering of what Gliese 876 system may be like, Copyright Lynette Cook.
Used with permission. Please visit her site at http://extrasolar.spaceart.org/

"Two Jupiter sized planets orbit around the dim Red Dwarf Gliese 876, both in the habitable zone.  It's a strong possibility that one of them may have a large habitable earth like moon.  Closer to this star is a 3rd planet, a huge earth sized world, likely with a surface of rock and lava."
Official Name Gliese 876
Class M4V (variable Red Dwarf)
Mass 314.1 Jupiter masses or .30 MSun (mass Sun)
Diameter 417,000 km
Luminosity 0.0124 of the sun
Planets 3 (detected)
Distance from Sol
 15.3 LY (4.7 Parsecs)
  Official Name
  WoOS Pet Name
  Designation
  Class
 

Mass
  Diameter
  Orbit

Hades 1
Gliese 876 b
H, Hot Huge Planet
7.4 Earth Mass
16,000 km
0.02 AU 2 days


The second earth like world discovered, Gliese 876 b is so close to it's star it orbits it in only about 2 days! A very short year for such a huge planet.

Although massive at 7.4 earth masses, it only has a diameter of 1.2 times that of earth, an indication that like Mercury, it may be close to 70% iron, mostly metal instead of rock, and likely have a gravity about 5 times stronger then that of Earths.

Image used with NSF's public release rights, artist Trent Schindler
  Official Name
  WoOS Pet Name
  Designation
  Class
 

Mass
  Diameter
  Orbit
 
 
Gliese 876 c
G, Water Gas-Giant Planet
0.54 Jupiter Mass
approx 1/2 Jupiter's
0.13 AU 30 Days

One of the two Gas Giants of this system, and within the habitable zone for planets.  It's warm enough that even though it may have a mostly hydrogen atmosphere like our own Jupiter, it would have water and ice clouds, much like out own earth does.  It's also a possibility that it may be a true water giant.  The two giants are locked into a 2:1 resonance orbit.
  Official Name
  WoOS Pet Name
  Designation
  Class
 

Mass
  Diameter
  Orbit
 
 
Gliese 876 d
G, Water Gas-Giant Planet
1.9 Jupiter Mass
approx 1.7 Jupiter's
0.2 AU 60 Days

One of the two Gas Giants of this system, and within the habitable zone for planets.  It's warm enough that even though it may have a mostly hydrogen atmosphere like our own Jupiter, it would have water and ice clouds, much like out own earth does.  It's also a possibility that it may be a true water giant.  The two giants are locked into a 2:1 resonance orbit.