DS Crucis (HR 4876, HD 111613) is a

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as ...

near 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, and ...

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. It is in the constellation

Crux 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 c ...

Location

DS Crucis is one of the brightest stars in the region of the NGC 4775 open cluster, better known as the Jewel Box Cluster, but its membership of the cluster is in doubt. The cluster is part of the larger Centaurus OB1 association and lies about 8,500 light years away. DS Crucis and NGC 4755 lie 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.

Variability

DS Crucis is a variable star with an amplitude of about 0.05 magnitudes. It was found to be variable from the photometry performed by the

Hipparcos ''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial obj ...

satellite. The variability type is unclear but it is assumed to be an

α Cygni variable Alpha Cygni variables are variable stars which exhibit non-radial pulsations, meaning that some portions of the stellar surface are contracting at the same time other parts expand. They are supergiant stars of spectral types B or A. Variations in ...

Properties

DS Crucis is an A1

bright supergiant In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

(luminosity class Ia), although it has also been classified as A2 Iabe. It is nearly 80,000 times the luminosity of the sun, partly due to its higher temperature of 9,000 K, and partly to being over a hundred times larger than the sun. The κ Crucis cluster has a calculated age of 11.2 million years, and DS Crucis an age of seven million years.

References

{{DEFAULTSORT:DS Crucis Crux (constellation) 111613 B-type supergiants 062732 4876 CD-59 4432 J12511794-6019473 Alpha Cygni variables Crucis, DS