7. B3
The blend Si II 4128-4130 is stronger than at class B2, relative to
He I 4121. The luminosity classification depends on the ratios
3995:
4009 and
4121:
4144 and on the appearance
of the wings of the H lines.
| Star | MKK | a |  | m | HD | Notes |
 Cas..... | B3 III | 01:47 | +63°11' | 3.4 | B3 | 1 |
 Aur..... | B3 V | 04:59 | +41 06 | 3.3 | B3 | |
 Aur..... | B3 I | 05:26 | +32 07 | 4.9 | B1 | |
| o2 CMA... | B3 I | 06:58 | -23 41 | 3.1 | B5p | |
| UMa.... | B3 V | 13:43 | +49 49 | 1.9 | B3 | 2 |
 Her..... | B3 IV | 17:36 | +46 04 | 3.8 | B3 | |
 Sgr..... | B3 IV-V | 18:49 | -26 25 | 2.1 | B3 | |
| 55 Cyg.... | B3 I | 20:45 | +45 45 | 4.9 | B2 | |
| NOTES | ||||||
| 1. The lines He I 4026 and 4471 are considerably weaker than in other B3 stars. The broad H wings observed for stars of luminosity class V are not seen. | ||||||
| 2. A very broad, faint K line has been observed on
low-dispersion
spectra of
UMa. This line appears to be definitely stellar in origin.
| ||||||
 |
| High resolution image |
