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The stars Acrux+Acrux B, the planetary nebula PK 299-0.2 and
the open star cluster van den Bergh-Hagen 131 |
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Object description:
« « The
planetary nebula PK 299-0.2. The object
appears more as a small H-II region and is also cataloged as
GN 12.17.2.01 and RCW
64, but is listed as a planetary nebula in the Aladin/Simbad database
with an extent of 4 arcmin. More detailed information about the object is not
available. GN 12.23.8 is an extremely faint H-II
region.
« Click here or on the thumbnail to load a large, annotated
image version. |
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For
the open star cluster van den Bergh-Hagen 131 no
further information is available except for the apparent diameter of nearly 5
arcminutes.
« Acruxis (possibly)
a quadruple star system, consisting of two blue, luminous stars of spectral
classes B1 and B2 (Acrux a1 and Acrus a2) and a somewhat fainter component of
spectral class B4 (Acrux B) at a very wide distance to the two main components,
which are nearly equally bright (Acrux a1 is also a spectroscopic double
star.
Acrux B has the same distance to the solar system and also the
same proper motion and direction as Acrux a1 and a2, but whether it really
belongs to the Acrux a1 and a2 system is uncertain.
Acrux a1 and a2
appear in distinct blue color in visual observation. To separate the components
visually it requires a telescope aperture of 5 to 6 inches, the apparent
separation is currently 4 arcseconds. The distance to the solar system is 312
light years, the orbital period of the main components is about 1500
years.
The image on the left is an old "lucky imaging" image of Acrux
a1/a2 and Acrux B, taken in the primary focus of the Celestron C14 Tlescope.
Further imaging information is unfortunately no longer available. |
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All Images and all Content are ©
by Franz Hofmann + Wolfgang Paech |