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5. B1

The blend at lambdalambda 4640-4650 is fairly uniform in intensity; the red edge may still be slightly stronger, however. Si III 4552 is stronger than Si IV 4089, and the broad blend near lambdalambda 4070-4076 is well marked. The line ratios used for luminosity classification are lambda 3995: lambda 4009, lambda 4121: lambda 4144, lambda 4144: lambda 4416, and lambda 4387: lambda 4416. The Si III lines and the wings of the H lines are also sensitive to luminosity differences.

TABLE 5
STANDARDS AT B1

Star MKK a delta m HD

o Per..... B1 IV 03:38 +31° 58' 3.9 B1
zeta Per..... B1 I 03:47 +31 35 2.9 B1
eta Ori..... B1 V 05:19 -02 29 3.4 B1
beta CMa.... B1 II-III 06:18 -17 54 2.0 B1
epsilon CMa.... B1 II 06:54 -28 50 1.6 B1
rho Leo..... B1 I 10:27 +09 49 3.9 B0p
a Vir..... B1 III-IV 13:19 -10 38 1.2 B2
sigma Sco.... B1 III 16:15 -25 21 3.1 B1
beta Cep.... B1 IV 21:27 +70 07 3.3 B1

Plate 10. Luminosity Effects at B1
Plate 10
High resolution image

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