27. G0

The spectral type is determined from the ratios 4045: H and 4226: H. Luminosity differences are well shown by the ratios 4077: 4226, and 4077: 4045 and for the high-luminosity stars by 4077: H.

TABLE 22
STANDARDS AT G0

Star	MKK	a		m	HD	Notes
Cas A..	G0 V	00:43	+57°17'	3.6	F8
Tri........	G0 V	02:10	+33 46	5.1	G0
Per........	G0 V	03:01	+49	14 4.2	G0
1 Ori.....	G0 V	05:48	+20 15	4.6	F8
Hya......	G0 III	08:41	+06 47	3.5	F8	1
47 UMa...	G0 V	10:53	+40 58	5.1	G0
UMa....	G0 V	11:12	+32 06	3.9	G0	2
CVn....	G0 V	12:29	+41 54	4.3	G0
Com....	G0 V	13:07	+28 23	4.3	G0
Boo......	G0 IV	13:49	+18 54	2.8	G0
Her......	G0 IV	16:37	+31 47	3.0	G0
NOTES
1. The absorption extending toward the violet from 4215 is faintly present.
2. Integrated light of system.

Plate 39. The Cepheid Variable X Cygni

High resolution image

Plate 40. Luminosity Effects at G0

High resolution image