Delta Scorpii

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Delta Scorpii A
Observation data
Epoch J2000
Constellation
(pronunciation)		 Scorpius
Right ascension 16h 00m 20.0s
Declination -22° 37′ 18″
Apparent magnitude (V) 2.29
Characteristics
Spectral type B0.2 IV
U-B color index -0.909
B-V color index -0.124
Variable type Gamma Cass
Astrometry
Radial velocity (Rv) -7 km/s
Proper motion (μ) RA: -8.67 mas/yr
Dec.: -36.9 mas/yr
Parallax (π) 8.12 ± 0.88 mas
Distance approx. 400 ly
(approx. 120 pc)
Absolute magnitude (MV) -3.16
Details
Mass ? M☉
Radius 5 R☉
Luminosity 14,000(bolometric) L☉
Temperature ? K
Metallicity ?
Rotation 181 km/s.
Age ? years
Other designations
Dschubba, Dzuba, Al Jabba, Iclarkrau, Iclarkrav, 7 Scorpii, HR 5953, BD -22°4068, HD 143275, SAO 184014, CCDM 16003-2237, FK5 594, HIP 78401.

Delta Scorpii (δ Sco / δ Scorpii) is a star in the constellation Scorpius. It also has the traditional name Dschubba (or Dzuba) or also Iclarcrau or Iclarkrav.

Because Delta Scorpii is near the ecliptic it is occasionally occulted by the Moon, or (extremely rarely) by planets.

[edit] Variability

In June 2000, Delta Scorpii was observed by Sebastian Otero to be 0.1 magnitudes brighter than normal. Its brightness has varied since then and has reached as high as magnitude 1.6 or 1.7, altering the familiar appearance of Scorpius. Spectra taken after the outburst began have shown that Delta Sco is throwing off luminous gases from its equatorial region. As of 2005 the flareup continues. Although the brightness varies, it remains well above its previous constant magnitude.

[edit] Companion stars

Dschubba is accompanied by a class B star that orbits the primary every 20 days at a distance comparable to the distance from the Sun to Mercury. Furthermore, there is a star that takes about 10 years to orbit Dschubba in a highly eccentric orbit that takes it close in to the primary once a decade. The last close encounter of these two stars happened in mid-2000 and it may have triggered the outburst of the primary star. A possible fourth companion star lies at about twice the distance again from the main star.

[edit] External links