DU Crucis

DU Crucis

The centre of NGC 4755, with DU Cru at top right Credit: NASA/ESA and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain)
Observation data Epoch J2000      Equinox J2000
Constellation	Crux
Right ascension	12h 53m 41.33485s[1]
Declination	−60° 20′ 57.9647″[1]
Apparent magnitude (V)	7.45[2]
Characteristics
Spectral type	M2- Iab[3]
U−B color index	+2.57[2]
B−V color index	+2.22[2]
Variable type	Lc[4]
Distance		2,600[7][8] pc
Absolute magnitude (MV)	−5.52[9]
Details[9]
Radius	568[10] R☉
Luminosity	52,000 - 53,000[10] L☉
Temperature	3,660±170[10] K
HIP 62918, SAO 252073, 2MASS J12534132-6020578, IRAS  12506-6004
Database references
SIMBAD	data

DU Crucis is a

, which is also known as the Kappa (κ) Crucis Cluster or Jewel Box Cluster.

Location

DU Crucis is one of the brighter members of the Jewel Box Cluster and the brightest red supergiant, strongly contrasting with the other bright members which are blue supergiants.^[11] 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

.

Properties

DU Crucis is an M2 intermediate luminosity supergiant (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.^[7]

Variability

Photometry from the Hipparcos satellite mission showed that DU Crucis varies in brightness with an amplitude of 0.44 magnitudes.^[13] No periodicity could be detected in the variations and it was classified as a slow irregular variable of type Lc, indicating a supergiant.^[4]

References

External links

• NASA Astronomy Picture of the Day: NGC 4755: A Jewel Box of Stars (17 August 2010)