Dschubba — Double Star in Scorpius
HIP 78401; Delta Scorpii; 7 Scorpii
About Dschubba
Description
Dschubba is a blue subgiant of spectral type B0.3IV at magnitude 2.32 in Scorpius. Located about 400 light-years from Earth, it marks the central star of the Scorpion's head (or one of its claws). In 2000, Dschubba unexpectedly brightened by about half a magnitude and became a Be star, developing a gaseous disk — it had never shown this behavior before in recorded history.
Observing Tips
Dschubba sits at the head of Scorpius, forming a small line with Beta Sco (Graffias) and Pi Sco. It appears as a blue-white star. Its brightness has been variable since 2000, ranging between about 1.6 and 2.3, making it worth comparing with nearby stars of known brightness. Best observed June through August.
History
The name Dschubba comes from the Arabic 'al-jabha,' meaning 'the forehead.' Its unexpected transformation into a Be star in 2000 — after being stable for all of recorded history — was one of the most surprising stellar events observed in modern times.
Fun Facts
Dschubba's sudden transformation in 2000 from a normal B star to an emission-line Be star caught astronomers by surprise. A close periastron passage of its binary companion may have triggered mass transfer that created the gaseous disk. The star remains variable and unpredictable.
Observe
1Physical Properties
2Position & Identifiers
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Easy | Easy |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Multiple Star System Quadruple
Separation over time
Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.
Explore
7
Size Comparison
8
Compare Stars
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Spectral Classification
10
Hertzsprung-Russell Diagram
11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
15Stellar Notes
16
Light Travel Time Machine
17
Relativistic Travel
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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