Mercury-manganese star
A mercury-manganese star is a type of chemically peculiar star with a prominent spectral line at 398.4 nm, due to absorption from ionized mercury. These stars are of spectral type B8, B9, or A0, corresponding to surface temperatures between about 10,000 and 15,000 K, with two distinctive characteristics:
- An atmospheric excess of elements like phosphorus, manganese, gallium, strontium, yttrium, zirconium, platinum and mercury.
- A lack of a strong dipole magnetic field.
List
The following table includes the brightest stars in this group.| Name | Bayer or Flamsteed designation | Spectral type | Apparent visual magnitude |
| Alpheratz | α Andromedae | B8IVmnp | 2.06 |
| Gienah Corvi | γ Corvi A | B8III | 2.59 |
| Maia | 20 Tauri | B8III | 3.87 |
| χ Lupi | B9IV | 3.96 | |
| Muliphein | γ Canis Majoris | B8II | 4.10 |
| φ Herculis | B9mnp | 4.23 | |
| π1 Bootis | B9p | 4.91 | |
| ι Coronae Borealis | A0p | 4.98 | |
| κ Cancri A | B8IIImnp | 5.24 | |
| 14 Sagittae | B9p | 5.89 | |
| Dabih Minor | β Capricorni B | B9.5III/IV | 6.10 |
| HD 30963 | B9 III | 7.23 |