What kind of star is Schedar?
Schedar, catalogued as Alpha Cassiopeiae (α Cas), appears in the official constellation Cassiopeia. Its apparent visual magnitude is about 2.24; slight variability reported, while its estimated distance is about 228 light-years. Astronomers classify the object as K0 IIIa orange giant. 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.
Schedar is a K-type giant that expanded and cooled after consuming the hydrogen available in its core. Its atmospheric spectrum contains the absorption features expected from a cooler evolved star, while its total luminosity greatly exceeds the Sun’s because of its large surface area. Reports of small brightness changes exist, but it is not an obvious naked-eye variable like Algol or Gamma Cassiopeiae. Schedar’s line of sight passes through the rich Cassiopeia Milky Way, yet the star itself is much nearer than many young clusters and emission nebulae projected around the constellation.
The coordinate pair RA 00h 40m 30.44s, Dec +56° 32′ 14.4″ 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.
Schedar data at a glance
| Proper name | Schedar | Catalogue designation | Alpha Cassiopeiae (α Cas) |
|---|---|---|---|
| Constellation | Cassiopeia | Apparent magnitude | about 2.24; slight variability reported |
| Spectral or system type | K0 IIIa orange giant | Estimated distance | about 228 light-years |
| Right ascension (J2000) | 00h 40m 30.44s | Declination (J2000) | +56° 32′ 14.4″ |
Values are rounded for an observer-friendly overview. Consult the linked SIMBAD record for component-level identifiers, bibliography, measurement provenance and newer catalogue values.
The name Schedar
Schedar derives from Arabic ṣadr, “breast,” because the star marks the heart or breast of the seated queen in the classical figure.
The Arabic anatomical name aligned naturally with the Greek portrayal of Cassiopeia seated on a throne. Bayer assigned Alpha to Schedar, although Gamma Cassiopeiae can rival or exceed it during active phases; Bayer letters were never a guaranteed permanent brightness order. Older atlases contain several transliterations, including Schedir and Shedar. The IAU Working Group on Star Names selected Schedar as the standardized spelling in 2016.
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 Schedar
Cassiopeia appears as a W in autumn evenings and an M when inverted. Schedar is the lower central corner of the W beside Gamma Cassiopeiae. Its orange tint becomes easier to recognize when compared directly with Gamma Cassiopeiae’s blue-white light.
Circumpolar across much of the north and especially high on northern autumn evenings. 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.
Observation checklist
- Locate the central valley of Cassiopeia’s W; Schedar is the warmer bright star there.
- Compare it with blue-white Gamma Cassiopeiae immediately along the W.
- Use binoculars to explore the dense Milky Way field without expecting Schedar itself to resolve.
- At high northern latitudes, revisit it in different seasons to see the W turn into an M.
Interesting facts about Schedar
- Schedar is a K-type orange giant.
- Its Alpha designation does not always make it Cassiopeia’s brightest visible star.
- The name identifies the queen’s breast in the traditional figure.
- The Milky Way background around it is far more distant and structurally complex than the foreground star.
- Schedar’s variability is small and not an easy visual project.
Continue from Schedar into the night sky
Use the Cassiopeia constellation guide to place this star within its larger pattern. When you are ready to observe, compare dark-sky places, find a nearby observatory, or follow our practical guide to finding a star in the night sky. Symbolically registered names are kept separately in the searchable Star-Register catalogue.
Sources and further reading
Measurements are rounded for readability. Multiple systems, variable stars and distant supergiants can have component-specific or model-dependent values. Survey panels show photographic sky fields, not the physical surface of the star.