Alsephina — Double Star in Vela
HIP 42913; Delta Velorum
About Alsephina
Description
Delta Velorum is a white main-sequence star of spectral type A1V at magnitude 1.96 in Vela. Located about 80 light-years from Earth, it has a luminosity of roughly 56 times solar. It is actually a triple or quadruple star system, and is also an eclipsing binary with a period of about 45 days, making it one of the brightest eclipsing binaries in the sky.
Observing Tips
Delta Vel is a member of the False Cross asterism, along with Kappa Vel, Iota Car, and Epsilon Car. It appears as a bright white star in the southern Milky Way. Its eclipsing binary nature causes brightness dips of about 0.4 magnitude — noticeable to careful visual observers. Best observed January through May from southern latitudes.
History
Delta Velorum has no traditional proper name. Its eclipsing binary nature was discovered relatively recently (in the 1990s by the Hipparcos satellite). As part of the False Cross, it has been a source of navigational confusion for centuries among sailors in the southern seas.
Fun Facts
Delta Vel is one of the brightest eclipsing binary stars in the sky, with brightness drops large enough to detect visually. The Hipparcos satellite's discovery of its eclipses was a surprise — this very bright star's variability had gone unnoticed for centuries.
Observe
1Physical Properties
2Position & Identifiers
3How easy to split?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | V. hard | V. hard | V. hard |
| 150 mm Newton 150mm Newt. | V. hard+ | V. hard+ | V. hard+ |
| Celestron C8 (203 mm SCT) C8 203mm | Hard | Hard | Hard |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Multiple Star System Quadruple C,E: optical
Separation over time
Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.
Eyepiece View
A: 2.0 · B: 5.6 · Sep: 1.3″ · PA: 185° · N up, E right
Unresolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
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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