.... 1500 najjaśniejszych gwiazd leżących w odległości 250 lat świetlnych.
Wszystkie gwiazdy są jaśniejsze od Słońca i większość z nich może być widzina
gołym okiem. Około jedna trzecia wszystkich gwiazd widocznych nieuzbrojonym
okiem leży w odległości 250 lat świetlnych...
Z grubsza 80 procent wszystkich gwiazd we Wszechświecie to czerwone karły, a
najbliższa nam gwiazda- Proxima Centauri- jest ich typowym przedstawicielem.
wszechswiat.astrowww.pl/250lys.gif
wszechswiat.astrowww.pl/12lys.gif
Except for a few objects as Lalande 21185 and Kapteyn's Star, astronomers
believe that Sol and most of its nearest neighbors were born in the Milky Way's
"thin disk." A few (such as Barnard's Star and Kapteyn's Star) may be more than
10 billion years old. By comparison, Sol is middle-aged at almost 4.6 billion
years old, while younger stars with only a few hundred million years include the
Sirius binary system, Altair, Fomalhaut, and Vega.
....
Within 10 pc of Sol, astronomers may have detected planets only in the Solar
System and only four other stars (Lalande 21185, Epsilon Eridani, Gliese 876 /
Ross 780, and AU Microscopii), as of early March 2005. Other than Sol itself,
however, only around perhaps 45 main-sequence stars of spectral types F5 to K5
in some 37 star systems (including such G stars as Tau Ceti, and Alpha Centauri
A) may possibly be capable of hosting Earth-type planets in stable orbits within
their respective circumstellar habitable zones (CHZs). Within a CHZ orbit,
liquid water vital to Earth-type plants and animals should persist on a
planetary surface without tidal locking, orbital disruption from another
celestial object, frequent flares and super flares, and other luminosity
variations from stars evolving of the main sequence as subgiants, giants, or
supergiants.
www.solstation.com/stars/pc10.htm
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