Stig Östlund

måndag, november 19, 2018

Barnard's Star b, or GJ 699 b

An alien world orbiting Barnard's Star, a tiny red dwarf that's only six light-years away, making it the second-closest known exoplanet beyond our solar system. Known as a "super-Earth," the planet (designated Barnard's Star b, or GJ 699 b) is thought to be at least 3.3 times the mass of Earth and orbits its star once every 233 days.
Barnard's Star is the fourth-closest star to our sun. Alpha Centauri's triple-star system (including Alpha Centauri A and B, plus Proxima Centauri) are the only stars nearer. Proxima Centauri is the closest star to have a known exoplanet in orbit, Proxima Centauri b. That world is slightly more massive than Earth, is located only 4.2 light-years away and has been pelted by solar flares, dashing hopes of it hosting life.

Ljuset från Barnards stjärna - som tros vara dubbelt så gammal som vår stjärna -  är mycket svagare än vad vi får från vår stjärna. 
Det är kallt på den här nyupptäckta planeten. Man tror att det är omkring minus 170 grader C. Knappast beboelig alltså. 
(se f.ö. --> https://sv.wikipedia.org/wiki/Barnards_stj%C3%A4rna 
och --> https://sv.wikipedia.org/wiki/Edward_Barnard)



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