DU Crucis is a

red supergiant Red supergiants (RSGs) are stars with a supergiant luminosity class ( Yerkes class I) of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive or luminous. Betelgeuse and Ant ...

and

slow irregular variable A slow irregular variable (ascribed the GCVS types L, LB and LC) is a variable star that exhibit no or very poorly defined periodicity in their slowly changing light emissions. These stars have often been little-studied, and once more is learnt a ...

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 (κ) Crucis Cluster or Jewel Box Cluster.

Location

A Snapshot of the Jewel Box cluster with the ESO VLT

DU Crucis is one of the brighter members of the Jewel Box Cluster and the brightest

, strongly contrasting with the other bright members which are

blue supergiant A blue supergiant (BSG) is a hot, luminous star, often referred to as an OB supergiant. They have luminosity class I and spectral class B9 or earlier. Blue supergiants are found towards the top left of the Hertzsprung–Russell diagram, above ...

s. It is part of the central bar of the prominent letter "A"-shaped 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 is just to the south-east of β Crucis, the lefthand star of the

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

DU Crucis is an M2 intermediate luminosity

supergiant Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars spa ...

(luminosity class Iab). Despite its low temperature, it is 46,600 times the luminosity of the sun, due to its very large size. The κ Crucis cluster has a calculated age of 11.2 million years.

Variability

Photometry from the Hipparcos satellite mission showed that DU Crucis varies in brightness with an amplitude of 0.44 magnitudes. No periodicity could be detected in the variations and it was classified as a slow irregular variable of type Lc, indicating a supergiant.

References

External links

* {{DEFAULTSORT:DU Crucis Crux M-type supergiants 062918 CD-59 4459 J12534132-6020578 Slow irregular variables IRAS catalogue objects Crucis, DU