F6IV MK43 standard: sig02 UMa - F6IV tau Boo - F6IV tet Boo - F6IV gam Ser - F6IV xi Peg - F6III-IV JM53 standards: alf Tri - F6IV 40 Leo - F6IV tet UMa - F6IV Morgan71 standard: alf Tri - F6IV MorganAbt72 standards: alf Tri - F6IV HR 4843 - F6IV MK73 standard: alf Tri - F6IV Cowley74 standards: alf Tri - F6IV 40 Leo - F6IV Cowley76 standards: alf Tri - F6IV 40 Leo - F6IV HR 4843 - F6IV GrayNstars standard: alf Tri - F6IV (B-V)(F6IV) = 0.449 ; exemplar HD 133484 = HR 5612 (B-V)(F6IV) = 0.469 ; poly fit to FGKIV standards & exemplars (B-V)(F6IV) = 0.471(+-0.016 sem,+-0.033 stdev) ; SIMBAD median F6IV d<75pc,V<6.5(N=6) (B-V)(F6IV) = 0.473 ; var. stan. 40 Leo = HD 89449 (F6IV-V) (B-V)(F6IV) = 0.488 ; pri. stan. alf Tri = HD 11443 => adopt (B-V)(F6IV) = 0.47 [updated 2/3/2022] Mv(F6IV) = 1.98 ; pri. stan. alf Tri = HD 11443 Mv(F6IV) = 2.2 ; GrayCorbally09 Mv(F6IV) = 2.29(+-0.17 sem,+-0.47 stdev) ; SIMBAD median F6IV d<75pc,V<6.5(N=6) Mv(F6IV) = 2.71 ; exemplar HD 133484 = HR 5612 Mv(F6IV) = 3.16 ; var. stan. 40 Leo = HD 89449 (F6IV-V) Teff(F6IV) = 6321K ; pri. stan. alf Tri (~solar metallicity) # Primary Standard alf Tri = HR 544 = HD 11443 = HIP 8796 (J0153+2934; V=3.4) *F6IV: JM53,MK73,Cowley74(stan),Gray01,Gray03 F7IVab: Barry70(uv metals weak) F5III: MK43,Abt09 F5IV: Roman52(lines weak) F6: Fekel03 Adopt "F6IV" from JM53 and MK73. Listed as F6IV standard by JM53, MK73, Morgan71, MorganAbt72, Cowley74, GrayNStars, Houk. V=3.42(HIP), B-V=0.488+-0.009(HIP), V-I=0.55+-0.03(HIP). plx=51.50+-0.23(HIP2) => Mv=1.98. logg=3.91(Balachandran90), [Fe/H]=0.00(Balachandran90). Teffs: 6288K(Balachandran90), 6321+-57K(Blackwell98), 6400+-80K(Casagrande11) => Teff=6321K. # Variant Standard 40 Leo = HD 89449 = HR 4054 = HIP 50564 (J1019+1928) F6IV: Jaschek78(JM53),Jaschek64(most),Cowley74(stan) *F6IV-V: Gray03 F6IVb: Barry70(uv metals strong) F6V: Roman50 F5: Cannon Star is ~0.47 mag above MS for its color. V=4.79(HIP), B-V=0.452+-0.006(HIP), B-V=0.473+-0.003(TYC), V-I=0.53+-0.03(HIP). plx=47.1255+-0.1679mas(GaiaEDR3) => Mv=3.16. PASTEL: =6486K(N=3), =4.13(N=3), <[Fe/H]>=0.12(N=3). # Exemplars HD 133484 = HR 5612 = HIP 73637 F5IV-V: Cowley79 *F6IV: Cowley76,Harlan81 V=6.59(HIP), B-V=0.449+-0.005(HIP), V-Ic=0.52+-0.01(HIP). plx=16.7819+-0.1221mas(GaiaEDR3) => Mv=2.71 => 0.75 mag above MS. # Deprecated Standards HD 82328 = HR 3775 = HIP 46853 = tet UMa F6IV: JM53,Slettebak55,Jaschek64(most),Abt81 F6III-IV: Keenan53 F6III: MK43 F7V: Abt09 F7IVab: Barry70 *F5.5IV-V: Gray03 F8p: Cannon Not great agreement. F5.5-F7 and III through IV in the post-JM53 literature. B-V=0.475, Mv=2.52, dMv = -1.12. So it appears to be evolved. tau Boo = HD 120136 = HR 5185 = HIP 67275 F6: Bidelman85 F6V: Adams35,Morgan38 F6IV: MK43,Moore50 F7V: J53,Cowley76,Abt81 *F7IV-V: Gray01 HD 126660 = tet Boo = HIP 70497 = HR 5404 = GJ 549A F5: Bidelman85 F6IV: MK43 F6V: Bouigue59 *F7V: JM53,Barry70(uv metals vweak),Cowley76(stan),Gray01 F7II-III: Bouw81 (unlikely given its Mv) Spectroscopic parameters suggest it is approximately solar and dwarfish gravity. No Houk type. VSX lists it as variable with Vmax=4.02, Vmin=4.07. 11th magnitude companion B 70" away in Washington Double Star catalog. B-V(HIP)=0.497+-0.005, V=4.04(HIP), V-I=0.59+-0.12(HIP). plx=68.82+-0.14mas(HIP2) => Mv=3.23 (~0.57 mag above MS). PASTEL: = 6280K(N=11), =4.29(N=5), <[Fe/H]>=-0.02(N=5). sig02 UMa = HD 78154 = HR 3616 F4V: Adams35,Westerlund53 F5V: Moore50 F6IV: MK43 F6V-IV: Cowley76 F7V: Abt81 # Other Stars WASP-18 = HD 10069 F6IV/V: Houk78 *F6V: [surface gravity and HRD position clearly show it to be dwarf] plx= 8.0694+-0.0241mas(GaiaDR2). Binary: CPM companion 26" away. V=9.270(Mermilliod91,Cousins62), V=9.28(HIP)), B-V=0.490(Mermilliod91,Cousins62). 2MASS: J=8.409+-0.018(2MASS), Ks=8.131+-0.027(2MASS). Prot=0.891369d(Oelkers18), vsini=10.9+-0.7km/s(Doyle13), vsini=11.9+-1.2km/s(Torres12), Mass=1.28+-0.09Msun(Doyle13),1.23+-0.08Msun(Mortier13), 1.37+-0.09Msun(Mortier13#2). Rad=1.29+-0.16Rsun(Doyle13). Teff=6226K(Brewer16),6368+-66K(Torres12),6526+-69K(Santos13,Mortier13). PASTEL: =6400K(N=5), =4.32(N=5), <[Fe/H]>=0.14(N=5). Teff is indeed typical for F6 stars. E(B-V)=0.002(Kervella19,STILISM). Assuming Av=0, Mv=3.80. Wright04 main sequence for B-V=0.49 => Mv=3.74, so this star is really on MS (also I get Mv=3.82 for FGK trend for d<25 pc stars for this B-V). This agrees with dwarf spectroscopic gravities: logg=4.37+-0.03(Torres12), logg=4.32+-0.09(Doyle13), logg=4.73+-0.08(Mortier13), logg=4.24+-0.17(Soto18). Companion: Gaia DR2 4931352153572401152. G=20.9168, plx= 9.4338+-1.5237mas(GaiaDR2) => M_G = 15.79+-0.35 (~M8.5). If you adopt plx for WASP-18, then M_G = 15.45 (~M8) But colors weird: Bp-Rp=1.8716, Bp-G=0.0801, G-Rp=1.7915.