الجدي vs Schedar
Two classes of the Harvard sequence lie between الجدي and Schedar, an F-type star and a K-type star in Cassiopeia. Seen from Earth the ranking is الجدي first at +1.97, Schedar second at +2.24. Intrinsically the balance shifts: الجدي carries an absolute magnitude of −3.64 against −1.98 for Schedar, making it about 4.6 times more luminous once distance is removed from the comparison. Distance divides them sharply — 433 light-years to الجدي against 228 for Schedar.
Property comparison
| Property | الجدي | Schedar |
|---|---|---|
| التسمية | 1Alp UMi | 18Alp Cas |
| الكوكبة | N/A | Cassiopeia |
| النوع الطيفي | Class F — F-type (Yellow-White) | Class K — K-type (Orange) |
| القدر الظاهري | +1.97 | +2.24 |
| القدر المطلق | -3.64 | -1.98 |
| المسافة | 433 ly | 228 ly |
| الكتلة | N/A | N/A |
| نصف القطر | N/A | N/A |
| درجة الحرارة | N/A | N/A |
| السطوع | N/A | N/A |
Full data for each star: الجدي · Schedar
Key differences
Key Differences
- ◆ Both are bright northern circumpolar stars useful for orientation near the north celestial pole.
- ◆ Polaris (F-type Cepheid) is currently ~0.7° from the true north pole; Schedar is the brightest star in the W-shaped Cassiopeia.
- ◆ Schedar is a K-type orange giant at ~228 light-years; Polaris is an F-type supergiant at ~431 light-years.
- ◆ Cassiopeia (containing Schedar) and Ursa Minor (containing Polaris) are on opposite sides of the pole.
- ◆ As the pole precesses, Schedar will become a closer pole star in the distant future.