G3IV

JM53, MK73, and Keenan89 do not list a G3IV standard.

Houk88 used zet Her as their G3IV standard, but mention that MK73
called the star a G1IV standard. Has been G0-G3 in literature, and is
tight 1.5" binary.

Among Gray03 and Gray06 stars within 40 pc (only HIP 61379 & 64150): 
B-V(G3IV) = 0.675 (+-0.008 sem, +-0.011 stdev; N=2)
V-I(G3IV) = 0.735 (+-0.005 sem, +-0.007 stdev; N=2)

(B-V)(G3IV) = 0.680 ; HD 109409 (only SIMBAD G3IV d<75pc,V<6.5)
(B-V)(G3IV) = 0.723 ; poly fit to FGK subgiant standards & exemplars
=> adopt (B-V)(G3IV) = 0.72 [updated 1/28/2022]

Mv(G3IV) = 3.0   ; GrayCorbally09 
Mv(G3IV) = 3.05  ; quadratic trend G0IV-K2IV standards+exemplars (for G3IV)
Mv(G3IV) =  3.089 ; G3IV HD_58895_ plx=20.03 mas, Vmag=6.581
Mv(G3IV) = 3.49  ; HD 109409 (only SIMBAD G3IV d<75pc,V<6.5)
=> adopt Mv(G3IV) = 3.05 [updated 1/28/2022]

Teff(G3IV) = 5590 K (fit between G2IV and G5IV)
=> adopt Teff(G3IV) = 5590 K [last updated 7/15/2017]


# Other Stars

HD 114174 
  G2IV-V: Harlan74
 *G3IV: Gray03
  G5IV: Roman55
  G6IV/V: Adams35