Kappa Crucis (κ Cru, HD 111973) is a
spectroscopic binary star in the
open cluster
An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, an ...
NGC 4755
The Jewel Box (also known as the Kappa Crucis Cluster, NGC 4755, or Caldwell 94) is an open cluster in the constellation Crux, originally discovered by Nicolas Louis de Lacaille in 1751–1752. This cluster was later named the Jewel Box by Jo ...
, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster.
Location
![A Snapshot of the Jewel Box cluster with the ESO VLT](https://upload.wikimedia.org/wikipedia/commons/c/c3/A_Snapshot_of_the_Jewel_Box_cluster_with_the_ESO_VLT.jpg)
κ Crucis is one of the brightest members of the open cluster that bears its name, better known as the Jewel Box Cluster.
[ It forms one leg, at bottom right or south, of the prominent letter "A" asterism at the centre of the cluster. The cluster is part of the larger Centaurus OB1 association and lies about 8,500 light-years away.
The cluster, and κ Cru itself, is just to the south-east of ]β Crucis
Mimosa is the second-brightest object in the southern constellation of Crux (after Acrux), and the 20th-brightest star in the night sky. It has the Bayer designation β Crucis, which is Latinised to Beta Crucis and abbreviated Beta C ...
, the lefthand star of the famous Southern Cross
Crux () is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name ''Crux'' is Latin for ...
.
Properties
κ Crucis is a B3 bright supergiant (luminosity class Ia). Radial velocity variations in the spectral line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to iden ...
s indicate that it has an unresolved companion star.[ It is over 100,000 times the ]luminosity of the Sun
The solar luminosity (), is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun.
One nominal ...
, partly due to its higher temperature over , and partly to its larger size. The κ Crucis cluster has a calculated age of 11.2 million years.[
]
References
External links
*
{{DEFAULTSORT:Kappa Crucis (star)
Crux (constellation)
Crucis, Kappa
111973
B-type supergiants
062931
4890
Durchmusterung objects
J12534890-6022344
Spectroscopic binaries