What kind of star is Spica?
Spica, catalogued as Alpha Virginis (α Vir), appears in the official constellation Virgo. Its apparent visual magnitude is about 0.97–1.04, while its estimated distance is approximately 250 light-years. Astronomers classify the object as Close B-type binary. These labels describe temperature, luminosity class or system components; they should not be read as a claim that every naked-eye point is a single isolated star.
The coordinate pair RA 13h 25m 11.58s, Dec −11° 09′ 40.75″ fixes the object’s direction on the celestial sphere for the J2000 reference epoch. Right ascension works like celestial longitude measured in hours, while declination works like latitude north or south of the celestial equator. Proper motion and improved measurements can refine catalogue positions, but these coordinates are sufficiently precise for a finder chart or planetarium search.
The name Spica
Latin spīca virginis means “the Virgin’s ear of grain.”
Modern professional catalogues retain identifiers such as the Bayer designation alongside a proper name. The International Astronomical Union standardizes which name belongs to which component—an important distinction for systems whose combined light looks like one star from Earth.
How to find Spica
Follow the Big Dipper mnemonic: arc to Arcturus, then continue the curve to speed on to Spica. Its blue-white colour contrasts strongly with orange Arcturus.
Visible from nearly all populated latitudes; best in northern spring and southern autumn. Visibility on a particular night still depends on latitude, season, time, horizon obstructions, weather and local light pollution. Use the interactive atlas below to check the surrounding field before observing.
Interesting facts about Spica
- Spica is a close spectroscopic binary whose components orbit in about four days.
- The two stars are far too close to split in ordinary amateur telescopes.
- Tidal distortion and pulsation produce subtle brightness changes.
- Spica participates in the Spring Triangle and, in some traditions, the Great Diamond.
- The Moon can occult Spica because it lies close to the ecliptic.
Sources and further reading
Measurements are rounded for readability. Multiple systems, variable stars and distant supergiants can have component-specific or model-dependent values.