G4V Garrison94 does not list a G4V anchor standard, nor does MK73 list a G4V dagger standard. There really aren't any G4V standards with a long history of consistent use (at least ones that aren't without issues). Keenan84 does not list G4 as a full subtype like G2 and G5, and "other possible subdivisions are utilized only for interpolation whenever we think that we can classify accurately enough to justify their use. Thus when we call a star G3 we mean only that it is closer to G2 than to G5." G2V and G5V have well-defined standards (Sun and kappa Ceti, respectively), and there is only a 150K difference between them. G3V and G4V are not particularly well-defined in terms of standards, as we'll see. Both of the standards that Keenan88 and Keenan89 decided upon for G4V are systematically redder (B-V ~ 0.71-0.72) than all other estimates for the mean color for G4V stars (typically B-V ~ 0.65-0.68). Keenan80 standard; 16 Cyg B (=HD 186427="16 Cyg fol.") - G4VM Keenan83 standard: 70 Vir (=HD 117176) - G4V HD 214850 (=HR 8631) - G4V KeenanYorka85 stan: HD 214850 (=HR 8631) - G4V 70 Vir (=HD 117176) - G4V Kleinmann86 standard: 16 Cyg B - G4V Keenan88 standard: 70 Vir (=HD 117176) - G4V HD 214850 (=HR 8631) - G4V Keenan89 standards: 70 Vir (=HD 117176) - G4V HD 214850 (=HR 8631) - G4V GrayCorbally09 stand: 70 Vir (=HD 117176) - G4V So for G4V standards, we're stuck with two stars whose colors are systematically redder compared to the mean colors of other G4Vs, and a star (16 Cyg B), which Keenan revised from being a G4V to being a G3V. Skiff08 flags two stars as G4V MK standards, both from Keenan89: HD 117176 (G4Va) & HD 214850 (G4V). Gray01/03/06 list 16 nearby G4V stars. Median HIP colors: (G4V) = 0.684 (+-0.006 sem, +-0.022 stdev; N=16) (G4V) = 0.740 (+-0.005 sem, +-0.018 stdev; N=16) For G4V Hipparcos stars within 75pc, with parallax S/N > 8, and within 1 mag of the MS (N=13): (G4V) = 0.663 (+-0.013 sem, +-0.034 stdev; N=13) (G4V) = 0.717 (+-0.011 sem, +-0.034 stdev; N=13) (G4V) = 1.212 (+-0.033 sem, +-0.091 stdev; N=13) (G4V) = 1.508 (+-0.030 sem, +-0.125 stdev; N=13) (G4V) = 1.597 (+-0.035 sem, +-0.095 stdev; N=13) (G4V) = 0.293 (+-0.014 sem, +-0.042 stdev; N=13) (G4V) = 0.088 (+-0.011 sem, +-0.037 stdev; N=13) (G4V) = 0.738 (+-0.011 sem, +-0.039 stdev; N=13) (G4V) =-0.074 (+-0.003 sem, +-0.013 stdev; N=13) (G4V) = 2.251 (+-0.045 sem, +-0.122 stdev; N=13) (B-V)(G4V) = 0.64 ; KenyonHartmann95 (B-V)(G4V) = 0.647 (+-0.011 sem,+-0.026 stdev); med. of 13 ARICNS G4V stars (B-V)(G4V) = 0.66 ; Fitzgerald70 (G4V) = 0.663 ; 13 HIP d<75pc (+-0.013 sem, +-0.034 stdev) (B-V)(G4V) = 0.665 ; Morgan71(halfway_G3V_G5V) (B-V)(G4V) = 0.67 ; interp between G2V (0.65) and G5V (0.68) (B-V)(G4V) = 0.676 ; median SIMBAD G4V d<25pc (N=8) (G4V) = 0.684 ; 16 Gray01/03/06 (+-0.006 sem, +-0.022 stdev) (B-V)(G4V) = 0.685 ; trend Gray G4Vs xHIP [Fe/H] vs. B-V (B-V)(G4V) = 0.687 ; exemplar HD 171665 = HIP 91287 ([Fe/H]=-0.03) (B-V)(G4V) = 0.70 ; median CATSUP d<30pc N=4 (B-V)(G4V) = 0.714 ; deprecated standard 70 Vir (B-V)(G4V) = 0.723 ; HR 8631 Keenan G4V standard => adopt (B-V)(G4V) = 0.670 *** [8/29/2019; linear interp G2V(0.65)-G5V(0.68)] => adopt (U-B)(G4V) = 0.168 => adopt (V-I)(G4V) = 0.730 => adopt (V-R)(G4V) = 0.372 => adopt (R-I)(G4V) = 0.358 => adopt (V-J)(G4V) = 1.232 => adopt (V-H)(G4V) = 1.536 => adopt (H-Ks)(G4V) = 0.075 => adopt (J-H)(G4V) = 0.304 (V-Ks)(G4V) = 1.593 +- 0.043 ; B-V vs. V-Ks for XHIP d<50pc G dwarfs (-0.1<[Fe/H]<0.1) for B-V=0.670 (V-Ks)(G4V) = 1.611 ; color trend for B-V=0.67 (V-Ks)(G4V) = 1.619 ; exemplar HD 171665 = GJ 9630 (V-Ks)(G4V) = 1.638 ; exemplar HD 207700 = HIP 108158 => adopt (V-Ks)(G4V) = 1.611 [updated 12/29/2020] (Ks-W1)(G4V) = 0.062 ; EEM trend for d<30pc for B-V=0.67 => adopt (Ks-W1)(G4V) = 0.062 [updated 12/29/2019] (Bp-Rp)(G3V) = 0.83 ; G3V adopted (Bp-Rp)(G4V) = 0.846 ; color trend for B-V=0.67 (Bp-Rp)(G4V) = 0.847 ; exemplar HD 171665 = HIP 91287 ([Fe/H]=-0.03) EDR3 (Bp-Rp)(G4V) = 0.854 ; exemplar HD 207700 = HIP 108158 ([Fe/H]=+0.04) EDR3 (Bp-Rp)(G5V) = 0.87 ; G5V adopted (Bp-Rp)(G4V) = 0.890 ; Evans18 trend for V-I= 0.730 (Bp-Rp)(G4V) = 0.8954 ; 70_Vir => adopt (Bp-Rp)(G4V) = 0.85 [updated 12/28/2020] (Bp-G)(G4V) = 0.338 ; exemplar HD 171665 = HIP 91287 ([Fe/H]=-0.03) EDR3 (Bp-G)(G4V) = 0.340 ; exemplar HD 207700 = HIP 108158 ([Fe/H]=+0.04) EDR3 (Bp-G)(G4V) = 0.349 ; color trend for B-V=0.67 (Bp-G)(G3V) = 0.36 ; G3V adopted (Bp-G)(G5V) = 0.38 ; G5V adopted (Bp-G)(G4V) = 0.4519 ; 70_Vir => adopt (Bp-G)(G4V) = 0.37 [updated 11/15/2020] ** CHECK ** (G-Rp)(G4V) = 0.4435 ; 70_Vir (G-Rp)(G3V) = 0.47 ; G3V adopted (G-Rp)(G5V) = 0.49 ; G5V adopted (G-Rp)(G4V) = 0.497 ; color trend for B-V=0.67 (G-Rp)(G4V) = 0.509 ; exemplar HD 171665 = HIP 91287 ([Fe/H]=-0.03) EDR3 (G-Rp)(G4V) = 0.514 ; exemplar HD 207700 = HIP 108158 ([Fe/H]=+0.04) EDR3 => adopt (G-Rp)(G4V) = 0.48 [updated 11/15/2020] ** CHECK ** (G-V)(G4V) = -0.209 ; exemplar HD 171665 PM* G4V DR2 (G-V)(G4V) = -0.193 ; HD 131923 PM* G4V (G-V)(G4V) = -0.188 ; HD 103493B PM* G4V (G-V)(G4V) = -0.188 ; HD 128041A PM* G4V (G-V)(G4V) = -0.180 ; HD 126525 PM* G4V (G-V)(G4V) = -0.175 ; exemplar HD 207700 = HIP 108158 DR2 (G-V)(G4V) = -0.173 ; G dwarf trend for G4V (G-V)(G4V) = -0.171 ; HD 89269 PM* G4V (G-V)(G4V) = -0.171 ; exemplar HD 171665 = HIP 91287 EDR3 (G-V)(G4V) = -0.170 ; HD 103743 PM* G4V (G-V)(G4V) = -0.166 ; HD 113319 PM* G4V (G-V)(G4V) = -0.162 ; HD 117939 PM* G4V (G-V)(G4V) = -0.162 ; HD 31865 PM* G4V (G-V)(G4V) = -0.162 ; exemplar HD 207700 = HIP 108158 EDR3 (G-V)(G4V) = -0.160 ; HD 4392 PM* G4V (G-V)(G4V) = -0.160 ; HD 99610 PM* G4VCN+0.5 (G-V)(G4V) = -0.156 ; HD 42618 PM* G4V (G-V)(G4V) = -0.109 ; HD 28255A PM* G4V (G-V)(G4V) = -0.086 ; HD 224465 PM* G4V => adopt (G-V)(G4V) = -0.173 [updated 11/1/2020] (g-r)(G4V) = 0.477 ; Covey07 interp G2V-G5V (g-r)(G4V) = 0.489 ; Jordi06 (V-R)=>(g-r) for V-R=0.372 (g-r)(G4V) = 0.501 ; Bilir05 (B-V)=>(g-r) for B-V=0.670 => adopt (g-r)(G4V) = 0.49 [updated 10/10/2020] Teff(G4V) = 5533 K ; weak stan. 70 Vir (PASTEL, see below) Teff(G4V) = 5534 +- 150 K ; vanBelle09 Teff(G4V) = 5593 K ; Ramirez05 Teff calibration for B-V=0.674 Teff(G4V) = 5611 K ; Boyajian12 Teff(G4V) = 5636 K ; interp. (G2V-G5V) GrayCorbally09 Teff(G4V) = 5664 K ; Teff from smoothed SpT(Teff) trend Teff(G4V) = 5666 K ; exemplar HD 207700 = HIP 108158 ([Fe/H] = +0.04) Teff(G4V) = 5677 K ; median Teff for 6 Gray03/Gray06 G4Vs with Valenti05 Teffs Teff(G4V) = 5678 K ; exemplar HD 171665 = HIP 91287 ([Fe/H] = -0.03) Teff(G4V) = 5690 K ; Teff for d<30pc [Fe/H]=+-0.1 dex dwarfs from Hinkel17 for B-V=0.672 => adopt Teff(G4V) = 5680 K (logT = 3.754) [updated 12/26/2020] BCv(G4V) = -0.110 mag ; Balona94(Teff=5680K) BCv(G4V) = -0.106 mag ; Bertone04(Teff=5680K,ATLAS) BCv(G4V) = -0.102 mag ; Flower96(Teff=5680K) BCv(G4V) = -0.102 mag ; EEM fit to Casagrande06/08/10 (Teff=5680K) BCv(G4V) = -0.101 mag ; Masana06(Teff=5680K) BCv(G4V) = -0.099 mag ; Bessell98(ATLAS9,logg=4.5,Teff=5680K) BCv(G4V) = -0.098 mag ; Casagrande18(Teff=5680K,logg=4.5) => adopt BCv(G4V) = -0.10 [last updated 8/29/2019, on scale where BCv(5772K)=-0.085] Mv(G4V) = 5.04 mag ; V-Ks=1.61 for EEM poly fit to SIMBAD d<25pc (1/2022) (M_Ks=3.43) Mv(G4V) = 5.04 mag ; exemplar HD 171665 = HIP 91287 ([Fe/H]=-0.03) Mv(G4V) = 5.0 mag ; GrayCorbally09 Mv(G4V) = 4.97 mag ; B-V=0.67 => interp G2V-G5V Mv(G4V) = 4.97 mag ; CATSUP -0.1<[Fe/H]<0.1 d<30pc for B-V=0.670 Mv(G4V) = 4.95 mag ; B-V=0.67 => EEM fit to SIMBAD dwarfs d<25pc Mv(G4V) = 4.93 mag ; Gray01/03/06 dwarfs, xHIP B-V/Mv, Gaspar16 |[Fe/H]|<0.05 "solar": fit for B-V=0.67 Mv(G4V) = 4.92 mag ; B-V=0.67 => Mv(Wright05) Mv(G4V) = 4.90 mag ; HD 117939 (metal poor) Mv(G4V) = 4.90 mag ; median SIMBAD G4V d<25pc (N=8) Mv(G4V) = 4.51 mag ; exemplar HD 207700 = HIP 108158 ([Fe/H]=+0.04) Mv(G4V) = 4.37 mag ; Wegner07 Mv(G4V) = 3.70 mag ; deprecated standard HD 117176 = 70 Vir => adopt Mv(G4V) = 4.93 mag [updated 9/26/2020] => adopt M_G(G4V) = 4.757 mag [updated 12/10/2020] (Mv=4.93,G-V=-0.173) => adopt M_Ks(G4V) = 3.319 mag [updated 12/30/2020] (Mv=4.93, V-Ks=1.611) logL(G4V) = -0.036 dex ; Mv=4.93, BCv=-0.10 => Mbol = 4.830 => adopt logL(G4V) = -0.036 dex [updated 12/26/2020] => adopt Mbol(G4V) = 4.830 mag [updated 12/26/2020] Rad(G4V) = 0.9907 sun ; logL=-0.036, Teff=5680K => adopt Rad(G4V) = 0.991 Rsun [updated 9/26/2020] Mass(G4V) = 0.985 Msun ; Ekers18 ML calibration for logL=-0.044 Mass(G4V) = 0.988 Msun ; EEM logL vs. Mass fit for binaries (logL=-0.044) Mass(G4V) = 0.99 Msun ; EEM Mv vs. Mass fit for binaries (Mv=4.95) Mass(G4V) = 0.994 Msun ; Ekers15 ML calibration for logL=-0.044 => adopt Mass(G4V) = 0.985 Msun [updated 10/23/2019] # No standards JM53, Wilson62, Morgan65, MK73, Houk75, KeenanMcNeil76, Keenan85, Corbally86, Keenan99, GrayNstars do not list any G4V standards. Houk does not treat G4 as a full type. # Deprecated Standards HD 117176 = 70 Vir = HR 5072 G2.5Va: Keenan80 G3: Bidelman85 G4V: Keenan85,Keenan89(G4Va),GrayCorbally09 *G4IV-V: Mamajek02 G5V: Adams53,JM53,Cowley67,Harlan70,Cowley76,Gray01 G5IV-V: MK43 G6IV-V: Moore50 This star is similar to 16 Cyg B in that its temperature type has moved around quite a bit over the years. Mamajek02 suggests "IV-V" may be a more appropriate luminosity class. The majority of Skiff07 refs show G5V, Keenan89 is only G4V, and Keenan80 had as G2.5V! The B-V=0.714 is redder than mean G4V (0.659). Given its range of published types by Keenan alone (G5 in MK43, G2.5 in Keenan80, and G4 in Keenan89), and fact it has lower surface gravity and brighter abs mag (Mv=3.70) than typical mid-G dwarfs - it should not be considered a dwarf standard. PASTEL mean parameters: Teff = 5533+-11K, [Fe/H] = -0.058+-0.006, logg=3.98+-0.03. Star is clearly evolved: Mv=3.70, which is 1.49 mag above the main sequence. Fuhrmann11 & Fuhrmann17 mention that 70 Vir is one of the oldest thin disk stars in solar neighborhood, and age estimates for the star place constraints on the maximum age of the thin disk. I came to same conclusion looking through CATSUP (FGK d<30pc) sample - if one looks for logg<4.1 stars, going cooler than 70 Vir, one finds solid thick disk star HR 173 = HD 3795, but no other evolved thin disk stars! V=4.976+-0.008(Mermilliod91), B-V=0.714+-0.007(Mermilliod91), U-B=0.262+-0.010(Mermilliod91) fbol = 28.050 (+-0.0248 stat., +-2% 'realistic') e-8 erg/s/cm2 (Kane15) => (28.050+-0.562)e-8 erg/s/cm2 => mbol = 4.8827+-0.0218 (IAU2015 scale) => BCv = mbol - V = 4.8827 - 4.976 = -0.093+-0.023. tetLD=0.998+-0.005mas(Kane15). plx = 55.8347 0.1730 mas(GaiaDR2) => GaiaDR2 plx => Rad = 1.9218 +- 0.0113 Rsun. R=1.9425+-0.0272Rsun (Kane15, interf), R=1.94+-0.05(Kane15,spec). The age seems fairly well-constrained around ~8 Gyr, at least from independent isochronal estimates: Age = 8.0+-0.1 Gyr(Bonfanti15), 7.77+-0.51Gyr(Kane15). 8.0(7.5-8.6) Gyr(Holmberg09), 7.89+0.23-0.22 Gyr(Ramirez12), 7.5(6.0-9.1) Gyr(Valenti05), 7.92(7.76-8.20) Gyr(Takeda07), 7.8(7.2-8.3) Gyr(Brewer16), 7.4(+-0.12% check is this fraction or really %?; Soubiran05). HD 186427 = 16_Cyg_B = HR 7504 = GJ 765.1B = "16 Cyg fol." (J1941+5031) G2V: Adams35,Gray01 G2.5V: Keenan83 *G3V: Keenan85,Keenan88,Keenan89,Gray03,Gray06 G4V: Keenan80 G4.5V: Stebbins57 G5V: JM53, Wilson62, KeenanMcNeil76(stan) 16 Cyg B has been considered a standard G2.5V, G3V, G4V, and G5V at different times by Morgan and Keenan. It appears that Keenan stopped at G3V in the 80s, and Gray03/06 adopted this (although Gray01 said G2V). I adopt Keenan's final "G3V" and consider it a primary standard. B-V[HIP]=0.661+-0.005. Mass = 0.99 Msun (Howard10), 0.97 Msun (Holmberg07) => median Mass = 0.98 Msun. PASTEL mean parameters: Teff = 5752+-8K, [Fe/H] = 0.064+-0.005, logg=4.36+-0.02. Mv=4.62. Both stars are consistent with being slightly metal-rich and slightly more evolved. Age = 7.0+-0.3 Gyr(Judge17). HD 214850AB = HR 8631 G3V: Adams35 *G4V: KeenanYorka85,Keenan88,Keenan89,Abt81,Garcia89 G5V: Christy69 Fair agreement on type at G4V, but alas it is really a SB2 with components G3V+G8V (P ~ 20 yr), which explains the unusually red B-V (0.723). # Exemplars Note that very few stars are classified G4V - I've selected some of the G4Vs from the Gray NStars papers on nearby stars that have near solar metallicity. HD 171665 = GJ 9630 = HIP 91287 = NLTT 46725 = SPOCS 806 = 2MASS J18371283-2540163 *G4V: Gray06 G5V: Evans66 G8: Bidelman85 V=7.43(HIP), V=7.435+-0.015(Mermilliod91), B-V=0.690+-0.010(Mermilliod91), B-V=0.687+-0.005(HIP), V-I=0.74(HIP), U-B=0.19(Mermilliod91). GaiaEDR3: plx=33.1479 0.0235mas, G=7.264232+-0.002767, E(BP/RP)=1.204, Bp-Rp=0.847050, Bp-G=0.337854, G-Rp=0.509195. J=6.194+-0.019(2M), H=5.971+-0.033(2M), Ks=5.816+-0.020(2M). V-Ks = 7.435 - 5.816 = 1.619. G-V = 7.264 - 7.435 = -0.171. PASTEL: =5678K(N=9), <[Fe/H]>=-0.03(N=7), =4.46(N=7). Mv = 5.04, M_G=4.87, M_Ks=3.42. HD 207700 = HIP 108158 = SPOCS 946 = NLTT 52323 = 2MASS J21544520-7326185 *G4V: Gray06 G5IV/V: Houk75 V=7.42(Mermilliod91), V=7.43(HIP), V=7.432+-0.006(Hauck97), B-V=0.696+-0.005(HIP), B-V=0.690(Mermilliod91), V-I=0.75(HIP), U-B=0.250(Mermilliod91), J=6.234+-0.024(2M), H=5.933+-0.040(2M), Ks=5.794+-0.017(2M). V-Ks = 7.432 - 5.794 = 1.638, GaiaEDR3: plx=26.0873+-0.0172mas, G=7.270075 0.002759, E(BP/RP)=1.206, Bp-Rp=0.853550, Bp-G=0.339576, G-Rp=0.513974. G-V = 7.270 - 7.432 = -0.162. Pecaut16: On average, Houk/Michigan G5V types map roughly to G4.5V on Gray/modern grid of G dwarf standards. PASTEL: =5666K(N=11), <[Fe/H]>=+0.04(N=10), =4.285(N=10). Mv = 4.51, M_G = , M_Ks= 2.876+-0.017. # Other Stars Morgan65 did not classify any Hyads as G4V. HD 117939 G3V: Adams35, Houk82 *G4V: Evans59, Gray06 [Fe/H]=-0.29 (Holmberg09), -0.23 (Favata97), -0.21 (Valenti05), Mv=4.90. Median publshed Teff = 5671 K (PASTEL, N=3). Old high velocity star: Holmberg09 lists U,V,W = 107, -40, -29 km/s, Takeda07 estimates age of 10.36 (7.92-12.64) Gyr. HD 178428 = HR 7260 G4V: Adams35 *G4V CN+0.5: Gray06 G4.5V: Keenan89 G5IV-V: Gray03 G5V: Hiltner69,Yoss77 G6: Bidleman85 Not good agreement on types, certainly not strong enough consistency to be considered a candidate standard. WDS lists as a 0.2" binary. WDS says it is 22-day binary. 104 Tau = HR 1656 = HD 32923 G1V: Adams35,Abt85,Gray03 G1IV: Hagen67 G4V: Roman52,Christy69,Bidelman85(G4) Tight binary. All spectral types seem to be for unresolved pair. Strange mix of published types hotward and coolward of Sun. Appears to be slightly cooler and slightly evolved compared to typical MS stars. PASTEL: = 5706K(N=10), =4.05(N=9), <[Fe/H]>=-0.20. HD 224465 # Search for another candidate G4V standard? Stars in Skiff's compendium (accessed 30 Dec 2011) which have been classified "G4V" by multiple classifiers: HD 16619: 1950ApJ...111..221W, 1969PASP...81..643C HD 28255a: 1964RGOB...85..207E, 2006A&A...460..695T HD 27989: 1962Obs....82...29J, 1969PASP...81..643C 104 Tau: 1952ApJ...116..122R, 1969PASP...81..643C HD 42618: 1935ApJ....81..187A, 1955ApJS....2..195R HD 68017: 1935ApJ....81..187A, 1955ApJS....2..195R HD 86728: 1935ApJ....81..187A, 1955ApJS....2..195R, 2003AJ....126.2048G HD 117939: 1959MNRAS.119..638E, 2006AJ....132..161G HD 128620: 2006AJ....132..161G, 1937AnHar.105...45H HD 178428: 1935ApJ....81..187A, 2006AJ....132..161G HD 179958: 1955ApJS....2..195R, 1968AJ.....73..350M HD 214059: 1935ApJ....81..187A, 1955ApJS....2..195R Comments on these stars: HD 86728: considered "G3Va Hdel1" standard by Keenan89. HD 28255A: but also G1V by Gray06 and Corbally84. HD 117939: see notes above. G4V, but a bit metal poor. HD 178428: see notes above. Gray and Keenan types inconsistent. Here is a list of the "G4V" stars classified in Gray03 or Gray06: HD 123 HD 4392 HD 23052 HD 86728 HD 89269 HD 113319 HD 117939 HD 126525 HD 131923 HD 149813 HD 171665 HD 188748 HD 207700 HD 224465 8 of these are in ValentiFischer05, and the one with metallicity closest to solar is HD 171665.