G4IV There appears to be no good normal G4IV standards. 24 UMa is weird. There aren't stars with default type G4IV in SIMBAD within 50 pc, so this subtype is exceedingly rarre. MK73 standard: 24 UMa (= HR 3771) - G4III-IV. GrayNstars standard: 24 UMa (= HR 3771) - G4IV Among Gray03 and Gray06 stars within 40 pc (only HIP 64408): B-V(G4IV) = 0.693 (N=1) V-I(G4IV) = 0.730 (N=2) (B-V)(G4IV) = 0.751 ; poly fit to FGK subgiant standards & exemplars => adopt (B-V)(G4IV) = 0.75 [updated 1/28/2022] Mv(G4IV) = 3.08 ; quadratic trend G0IV-K2IV standards+exemplars (for G4IV) Mv(G4IV) = 3.1 ; GrayCorbally09 => adopt Mv(G4IV) = 3.08 [updated 1/28/2022] Teff(G4IV) = 5567 K ; interp between G2IV (5620K) and G5IV (5540K) => adopt Teff(G4IV) = 5570 K [last updated 5/15/2017] # No standards JM53, Houk88, and Keenan89 do not list a G4IV standard. # Deprecated Standard 24 UMa = DK UMa = HD 82210 = HR 3771 (J0934+6949; V=4.6) *G9V_Fe-0.7: Gray03 G4III-IV: Haschek78(Slettebak55),MK73 G4IV: GrayNstars G0V(e): Li00(Halpha filled!) G5IV: Roman52(lines strong) G6IV: Abt86 G2IV: Gyldenkerne55 G5III-IV: Keenan89 G0: Cannon Jaschek64 lists 2 G4III-IV types, 4 G2IV types, and 4 G5IV types. All over the place from G0 to G9, and V to III. Published metallicities of [Fe/H] = -0.34 (McWilliams90) and -0.38 (Hearnshaw74), so slightly metal poor. Classified as RS CVn variable period in GCVS with period 0.92 day. X-ray bright (Lx= 10^29.9 erg/s) and Vsini = 4.9 km/s (Maggio+90). GrayNstars lists it as a G4IV standard, but Gray03 lists G9V_Fe-0.7. Probably not recommended for use as a standard. PASTEL values: = 5281K (N=2), <[Fe/H]> = -0.34 (N=1; 1990ApJS...74.1075M).