Mira vs Polaris
| 属性 | Mira | Polaris |
|---|---|---|
| 命名 | 68Omi Cet | 1Alp UMi |
| 星座 | N/A | N/A |
| 光谱类型 | Class M — M-type (Red) | Class F — F-type (Yellow-White) |
| 视星等 | +6.47 | +1.97 |
| 绝对星等 | 1.66 | -3.64 |
| 距离 | 299 ly | 433 ly |
| 质量 | N/A | N/A |
| 半径 | N/A | N/A |
| 温度 | N/A | N/A |
| 光度 | N/A | N/A |
主要差异
- ◆ Both are famous variable stars in the northern sky, though entirely different types.
- ◆ Polaris is a Cepheid variable that pulsates predictably and was used to calibrate the Cepheid distance ladder.
- ◆ Mira is a long-period Mira-type variable that can range from naked-eye visibility to complete invisibility.
- ◆ Polaris is celebrated as the North Star for its positional stability near the pole; Mira is celebrated as the first recognized variable star (1596).
- ◆ Polaris's pulsation amplitude has been shrinking over the past century; Mira continues its large-amplitude cycle.