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NGC 6169, NGC 6192 and the ellipsoidal variable star V 1003
Sco |
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Object description:
NGC 6169
(Collinder 306) is a small open cluster with about 40 stars in the
constellation Norma. The bright star in the center of the cluster is my Norma
with a magnitude 5 brightness. My Norma is a blue giant star of spectral type
B0 which shows a small brightness variation. It does not belong to any category
of variable stars. If my Norma belongs to the star cluster is not known for
sure. For the star a distance of 4200 +/- 1800, for the cluster 3300 lightyears
is given. The age of the cluster is estimated to 33 million years. NGC 6169 was
first observed by Friedrich Wilhelm Herschel in 1834, the discoverer is his
son, John Herschel, on June 1, 1836. |
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NGC 6192 is a - very old - open
star cluster in the constellation Scorpio. It contains about 60 stars with
magnitudes between 11th and 14th magnitude. According to Trumpler it is
classified as type I 2 p. The distance to the
solar system is about 5000 lightyears. NGC 6192 was discovered by James Dunlop
on May 13, 1826.
The star V 1003
Sco (HD 149 711) is a variable star
with a magnitude of just under 6th magnitude. It belongs to the relatively rare
examples of the so-called ellipsoidal variable stars. They are extremely close
binary systems in which the light change is triggered by a deviation from the
spherical shape of the stars. Due to the orbit around the common center of
gravity of both components the stars deform to ellipsoids and thus during one
orbit the visible area from Earth changes and the brightness of the whole
system fluctuates with low amplitude.
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All Images and all Content are ©
by Franz Hofmann + Wolfgang Paech |