G0.5V

Keenan80 standard:   HD 84737 (=HR 3881) - G0.5Va
Keenan83 standard:   del Tri (=HD 13974) - G0.5V
		     HD 84737 (=HR 3881) - G0.5Va
Keenan85 standard:   del Tri (=HD 13974) - G0.5V
                     HD 84737 (=HR 3881) - G0.5Va
Keenan89 standard:   del Tri (=HD 13974) - G0.5V Fe-0.5
                     HD 84737 (=HR 3881) - G0.5Va
Keenan99 standards:  HD 84737 (prim. stan.) - G0.5Va
                     del Tri (=HD 13974) - G0.5 V Fe-0.5 (prim. stan)

Teff(G0.5V) = 5888 K; Teff from smoothed SpT(Teff) trend
=> adopt Teff(G0.5V) = 5890 K [updated 10/27/2017]

BCv(G0.5V) = -0.063 [last updated 8/3/2018, on scale where BCv(5772K)=-0.08]


# Primary Standards

HD 84737 = HR 3881
 *G0.5Va: Keenan80,Keenan83,Keenan85,Keenan89,Keenan99(prim.)
  G0V: MK43,Gray01

# Variant

del Tri = HR 660 = HD 13974
  F9V: Abt85
  G0V: Maury1897(G0IV/V),Adams35,Keenan41,MK43,Ljunggren61,Keenan80,Bidelman85(G0),Gray01
  G0.5V: Keenan83,Keenan85
 *G0.5V Fe-0.5: Keenan89

  One of the G0V standards with the longest history and continuity,
  but Keenan89 switched subtype in his last compilation.
  Teff=5920K(Gray01), logg=4.31(Gray01), [M/H]=-0.21(Gray01),
  E(b-y)=0.02(Gray01). PASTEL compilation shows that most metallicity
  estimates are between [Fe/H] ~ -0.5 and -0.2, so clearly metal poor.  
  WDS shows is tight binary.