Gliese 777
2
Template: Infobox double star / Maintenance / single coordinate
Gliese 777 is a double star of the sixth magnitude in the constellation Cygnus. The one-star is a yellow subgiant with planetary companions, the other a red dwarf. The larger of the two stars can be observed under favorable conditions with the naked eye.
- 2.1 Gliese 777 From
- 2.2 Gliese 777 Ac
Physical Properties
Gliese 777 A
Gliese 777 A is the sun very similar star of spectral G6. Since the star with 6.7 billion years is significantly older than the sun was clear to him now more metal accumulate, hence its metallicity is about 70% higher than that of the sun. He has recently finished his nuclear fusion of hydrogen in its core and is now beginning to become a red giant swell. To date, two planets have been found orbiting Gliese 777 which A.
Gliese 777 B
Gliese 777 B is the second component of the binary system. He is a red dwarf, which orbits the primary star at a distance of 3000 AU, which corresponds to about one thousand times the distance from the primary star to his distant larger planetary companion. For a full encirclement end Gliese 777 B is likely to need tens of thousands. Since the observation is difficult under such circumstances, and it will focus on other objects is not known a lot more about the system.
The planetary system
Michel Mayor declared 2002 to have discovered a companion to Gliese 777 A, which orbits the star at a great distance. The mass of the newly discovered planet was calculated to be 1.5 times the mass of Jupiter. Also, the size of Jupiter is the very similar. Further observations showed more regular movements of the star with an amplitude of 17.1 days. This is seen as a strong indication of a further, but very small companion. The mass was estimated to be 18 times Earth's mass, which is considered extremely low. The virtually non-existent eccentricity of the companion (e = 0.01) is very striking.
Gliese 777 From
Gliese 777 Ab has, as already mentioned about 1,502 times the mass of Jupiter, takes about 2890 days to orbit its star and orbits it in a distance of 3.92 ± 0.17 AE. The eccentricity of the orbit is 0.36 ± 0.03. Due to its similarity with Jupiter, the planet is therefore also known as " Jupiter - twin"
Gliese 777 Ac
Gliese 777 Ac has only about 6% of the mass of Jupiter, required for a round about 17 days away from its star only 0.128 ± 0.002 AE and shows a very low orbital eccentricity of about 0.01.
METI message to Gliese 777
On the first of July 1999, it was sent by the largest European radar system, the 70 -meter Evpatoria Planetary Radar, a message in the direction of the binary system Gliese 777. Already in April 2051, the message will be receivable on Gliese - assuming it is there someone available and willing to listen.