G0III 31 Com is probably the best southernly accessible G0III standard (J1251+2732; V=4.9) The Morgan (early ; G) giant sequences meld nicely at G0III with 31 Com (JM43, MK73, MK78, Keenan89, Gray). MK43 standard: eps Hya - G0III JM53 standard: 31 Com (= HR 4883) - G0III Morgan65 standard: 31 Com (= HR 4883) - G0III Abt68 standard: 31 Com (= HR 4883) - G0III MorganAbt72 standards: 31 Com (= HR 4883) - G0III 81 Psc (=psi^3 Psc = HR 339) - G0III MK73 dagger standards: 31 Com (= HR 4883) - G0III 81 Psc (=psi^3 Psc = HR 339) - G0III Houk standard: 31 Com - G0III [from MK73] Cowley76 standard: 31 Com - G0III MK78 standard: 31 Com - G0III Turnshek85 standard: 31 Com (=HR 4883) - G0IIIp Keenan89 standard: 31 Com - G0IIIp GrayAtlas standard: 31 Com - G0III GrayNstars standard: 31 Com - G0III 81 Psc (=psi^3 Psc = HR 339) - G0III GrayCorbally10 standard: 81 Psc (=psi^3 Psc = HR 339) - G0III Gray01 classifies three stars as G0III or variant: HD 6903 (G0IIIa), HD 72779 (G0III), and HD 111812 (G0III). (J-H)(G0III) = 0.323 ; smoothed relation from giants in Skiff compendium w/i 15 deg of NGP, 2MASS photometry AAA flags (J-H)(G0III) = 0.355 (+-0.018 sem, +-0.118 stdev) ; N=57 G0III from Skiff compendium w/i 15deg of NGP, 2MASS photometry AAA flags => adopt (J-H)(G0III) = 0.323 [updated 10/30/2020] (H-Ks)(G0III) = 0.083 (+-0.004 sem, +-0.035 stdev) ; N=57 G0III from Skiff compendium w/i 15deg of NGP, 2MASS photometry AAA flags => adopt (H-Ks)(G0III) = 0.083 [updated 10/30/2020] B-V(G0III) = 0.671 ; pri. stan. 31 Com B-V(G0III) = 0.697 ; pri. stan. psi03 Psc (could be slightly reddened) => adopt B-V(G0III) = 0.67 [updated 10/30/2020] Mv(G0III) = 0.18 ; pri. stan. 31 Com # No standards Garrison94 does not list a G0III anchor standard. # Primary Standards 31 Com = HR 4883 = HD 111812 (J1251+2732; V=4.94) *G0III: JM53,Roman50,Abt68(stan),Harlan69,MorganAbt72(stan),MK73(dagger),Cowley76(standard),MK78,Gray01,GrayNstars G0IIIp: Turnshek85(stan),Keenan89(H & K weak) F8III: Bouw81 Adopt "G0III" from MK78, MK73, JM53. V=4.93(HIP), B-V=0.681+-0.014(HIP), B-V=0.671+-0.005(Mermilliod91), U-B=0.199+-0.004(Mermilliod91), V-I=0.70+-0.03(HIP). Mv=0.18, delta(Mv)=-4.81mag, plx=11.22+-0.23mas; likely negligible reddened. psi^3 Psc = 81 Psc = HR 339 *G0IIIa: Gray01 G0III: Harlan69,MorganAbt72(stan),MK73(dagger),Gray89,GrayNstars,GrayCorbally10 F9IIIa: Keenan89(stan) F5III: Adams35 Considered "G0III" by nearly everyone, but F9III by Keenan89. Part of the nebulous F9/G0 boundary between Morgan and Keenan's works. I adopt "G0IIIa" from Gray01 (following Morgan/Gray/Garrison/Corbally) vs. Keenan's "F9IIIa". V=5.57(HIP), B-V=0.697+-0.006(HIP), V-I=0.75+-0.04(HIP). plx=8.66+-0.27mas(vanLeeuwen07); can't assume negligibly reddened. # Deprecated standard eps Hya = HD 74874 (J0856+0625; V=3.4) *G5III+A8IV: Edwards76(combined "G3III") G0III: MK43 G0III-IV: Slettebak55 F0V+K1III:: Cowley76 dG6+A7+: Parsons98 F8V: Wilson50 F8III: Adams35 F8: Cannon G1III: Stephenson69 "close pair in 3" trip" in Skiff10 notes for Adams35. Clearly a poor choice for a standard in MK43, and unsurprisingly not considered a standard in later papers.