21 Cas
21 Cas
21 Cas is a A-type (White) star located in the constellation Cassiopeia. It carries the designation 21 Cas.
Located approximately 303.4 light-years from Earth, 21 Cas resides within the broader disk of our Milky Way galaxy.
21 Cas is classified as a spectral class A star (A-type (White)) on the Harvard spectral classification system.
With an apparent magnitude of +5.64, 21 Cas sits near the limit of naked-eye visibility. It can be glimpsed without optical aid under dark skies, but binoculars will make observation much easier. Observers will note its blue-white hue, which corresponds to a B-V color index of +0.078.
Physical Properties
| Spectral Class | Class A — A-type (White) |
| Color Index (B−V) | 0.078 |
Observation
| Apparent Magnitude | +5.64 |
| Absolute Magnitude | 0.80 |
| Distance | 303 ly |
| Constellation | Cassiopeia |
Position
| Right Ascension | 0h 45.65m |
| Declination | 74° 59.28′ |
Frequently Asked Questions
What type of star is 21 Cas?
21 Cas is a Class A — A-type (White) star.
How far is 21 Cas from Earth?
21 Cas is approximately 303.4 light-years from Earth.
Can you see 21 Cas with the naked eye?
With an apparent magnitude of 5.64, 21 Cas is visible to the naked eye.
What constellation is 21 Cas in?
21 Cas is located in the constellation Cassiopeia.