AAAA4V Garrison94 does not list a A4V anchor, and MK73 does not list a A4V dagger standard. del Leo (= HD 97603) is probabaly the best available standard. I've found that 49 Ori (HD 37507) may be a good candidate A4V standard -- we should get a spectrum of it. JM53 standard: del Leo (HD 97603) - A4V Houk75 standard: del Leo (HD 97603) - A4V (primary standard) Cowley69 standard: del Leo (HD 97603) - A4V For A4V Hipparcos stars within 75pc, with parallax S/N > 8, and within 1 mag of the MS (N=10): (A4V) = 0.181 (+-0.012 sem, +-0.045 stdev; N=10) (A4V) = 0.318 (+-0.036 sem, +-0.091 stdev; N=10) (A4V) = 0.379 (+-0.040 sem, +-0.106 stdev; N=10) (A4V) = 0.406 (+-0.044 sem, +-0.124 stdev; N=10) (A4V) = 0.058 (+-0.015 sem, +-0.044 stdev; N=10) (A4V) = 0.042 (+-0.013 sem, +-0.029 stdev; N=10) (A4V) = 0.181 (+-0.010 sem, +-0.040 stdev; N=10) (A4V) =-0.021 (+-0.005 sem, +-0.011 stdev; N=10) (A4V) = 0.569 (+-0.058 sem, +-0.160 stdev; N=10) (B-V)(A4V) = 0.11 ; Morgaa71(halfway_A3V-A5V) (B-V)(A4V) = 0.115 ; Schmidt-Kaler halfway(A3V-A5V) (B-V)(A4V) = 0.12 ; Fitzgerald70 (B-V)(A4V) = 0.125 ; halfway between A3V(0.09) and A5V(0.16) (B-V)(A4V) = 0.127 ; exemplar 24 CVn = HD 118232 (B-V)(A4V) = 0.127 ; smoothed trend SpT vs (B-V)o B9.5V-F3V 11/2021 (B-V)(A4V) = 0.128 ; prim. stan. del Leo (B-V)(A4V) = 0.139 ; exemplar A4V star 49 Ori (A4V) = 0.164 (+-0.010 sem, +-0.042 stdev) ; HIP d<75pc S/N>8 N=10 (B-V)(A4V) = 0.166 ; d<60pc SIMBAD N=6 (B-V)(A4V) = 0.174 ; exemplar xi Vir = HD 102124 => adopt (B-V)(A4V) = 0.14 *** [updated 9/20/2019] => adopt (U-B)(A4V) = 0.097 => adopt (V-I)(A4V) = 0.164 => adopt (V-R)(A4V) = 0.078 => adopt (R-I)(A4V) = 0.086 => adopt (V-J)(A4V) = 0.294 => adopt (V-H)(A4V) = 0.316 => adopt (V-Ks)(A4V) = 0.353 => adopt (H-Ks)(A4V) = 0.037 => adopt (J-H)(A4V) = 0.022 (Bp-Rp)(A4V) = 0.166 ; color trend for B-V=0.14 (Bp-Rp)(A4V) = 0.201 ; Evans18 trend for V-I=0.164 => adopt (Bp-Rp)(A4V)= 0.166 [updated 11/22/2020] (Bp-G)(A5V) = 0.051 ; color trend for B-V=0.14 => adopt (Bp-G)(A5V) = 0.051 [updated 11/22/2020] (G-Rp)(A4V) = 0.113 ; color trend for B-V=0.14 => adopt (G-Rp)(A4V) = 0.113 [updated 11/22/2020] (Ks-W1)(A4V) = 0.046 ; EEM trend for d<30pc for B-V=0.14 => adopt (Ks-W1)(A4V) = 0.046 [updated 12/29/2019] (G-V)(A4V) = -0.044 ; * 24 CVn PM* A4V (G-V)(A4V) = -0.035 ; HD 75171 PM* A4V (G-V)(A4V) = -0.029 ; * 82 Peg dS* A4Vn (G-V)(A4V) = -0.029 ; polynomial fit f(B-V) (G-V)(A4V) = -0.023 ; * 40 LMi PM* A4Vn (G-V)(A4V) = -0.022 ; * ksi Vir PM* A4V (G-V)(A4V) = -0.015 ; * 64 Gem PM* A4V (G-V)(A4V) = -0.003 ; fit for A dwarfs from Kervella19 corrected for E(B-V), eval for (V-Ks)=0.353 => adopt (G-V)(A4V) = -0.01 [updated 4/8/2022] (U-B)(A4V) = 0.09 ; Fitzgerald70 (U-B)(A4V) = 0.091 ; HIP d<75pc S/N>8 A4V N=35 (Mermilliod91 photometry) (g-r)(A4V) = 0.019 ; Jordi06 (V-R)=>(g-r) for V-R=0.078 (g-r)(A4V) = -0.094 ; Bilir05 (B-V)=>(g-r) for B-V=0.140 (g-r)(A4V) = -0.13 ; Covey07 interp A3V-A5V => adopt (g-r)(A4V) = -0.09 [updated 10/10/2020] Teff(A4V) = 7929 K ; Boyajian12 Teff(A4V) = 7993 K ; exemplar xi Vir = HD 102124 Teff(A4V) = 8116 K ; standard del Leo Teff(A4V) = 8163 K ; exemplar HD 37507 Teff(A4V) = 8180 K ; exemplar 24 CVn = HD 118232 = Teff(A4V) = 8192 K ; mean photometric Teff Teff(A4V) = 8222 K ; Zorec12 median Teff(A4V) = 8250 K ; median Teff for 3 A4V from Gray17 Teff(A4V) = 8260 K ; Theodossiou90 Teff(A4V) = 8267 K ; interp B-V vs Teff (A3V: B-V=0.1,8600K; A5V: B-V=0.16, 8100K) Teff(A4V) = 8269 K ; EEM N=63 Teffs Teff(A4V) = 8335 K ; interp. (A3V-A5V) GrayCorbally09 Teff(A4V) = 8460 K ; Schmidt-Kaler82 (halfway A3V-A5V) => adopt Teff(A4V) = 8250 K (logT = 3.917) [updated 2/10/2020] => adopt (B-V)(A4V) = 0.14 => adopt (V-I)(A4V) = 0.16 => adopt (V-J)(A4V) = 0.27 => adopt (V-H)(A4V) = 0.31 => adopt (V-Ks)(A4V) = 0.35 BCv(A4V) = -0.058 mag ; Flower96(Teff=8250K, BCv(5772K)=-0.085) BCv(A4V) = -0.055 mag ; pri. stan. HD 97603 = del Leo = HR 4357 (Boyajian13) BCv(A4V) = -0.030 mag ; Schmidt-Kaler82(BCv=-0.16 + 0.13 offset) BCv(A4V) = -0.020 mag ; EEM trend A3V(BCv=-0.04)-A5V(BCv=0.00) BCv(A4V) = -0.015 mag ; Code76(Teff=8250K, BCv(5772K)=-0.085) BCv(A4V) = -0.018 mag ; Bessell98(ATLAS,logg=4.5,Teff=8250K, BCv(5772K)=-0.085) BCv(A4V) = 0.002 mag ; Balona94(Teff=8250K, BCv(5772K)=-0.085) BCv(A4V) = 0.029 mag ; Bertone04(Teff=8250K,ATLAS, BCv(5772K)=-0.085) => adopt BCv(A4V) = -0.020 [updated 4/4/2020; set so that BCv(5772K)=-0.085] logg(A4V) = 4.0 ; median for 3 A4V from Gray17 Mv(A4V) = 2.05 mag ; interp. (A3V-A5V) GrayCorbally09 Mv(A4V) = 1.97 mag ; exemplar xi Vir = HD 102124 Mv(A4V) = 1.94 mag ; B/A/F dwarf sequence for B-V=0.14 Mv(A4V) = 1.78 mag ; median Mv for A6V calc using Kervella19 HIP & Gaia DR2 (d<100pc) Mv(A4V) = 1.77 mag ; d<60pc SIMBAD A4V (N=6) Mv(A4V) = 1.76 mag ; A dwarf B-V vs. Mv sequence for B-V=0.14 Mv(A4V) = 1.757 mag ; Wright05(B-V=0.14) Mv(A4V) = 1.73 mag ; linear B-V vs. Mv fit to d<50pc Gray01/03/06 dwarfs for B-V=0.14 Mv(A4V) = 1.70 mag ; d<60pc Mv(B-V=0.14) Mv(A4V) = 1.7 mag ; Schmidt-Kaler halfway (A3V-A5V) Mv(A4V) = 1.60 mag ; exemplar HD 37507 = HR 1937 = 49 Ori Mv(A4V) = 1.30 mag ; Wegner07 Mv(A4V) = 1.29 mag ; standard HD 97603 = Del Leo Mv(A4V) = 0.90 mag ; exemplar 24 CVn = HD 118232 => adopt Mv(A4V) = 1.94 [updated 9/24/2020] => adopt M_G(A4V) = 1.92 [updated 12/10/2020] (Mv=1.94, G-V=-0.02) => adopt M_Ks(A4V) = 1.587 [updated 12/30/2020] (Mv=1.94, V-Ks=0.353) logL(A4V) = 1.115 dex ; exemplar xi Vir = HD 102124 logL(A4V) = 1.128 dex ; Mv=1.94, BCv=-0.02 => Mbol = 1.920 logL(A4V) = 1.263 dex ; exemplar HD 37507 = HR 1937 = 49 Ori logL(A4V) = 1.386 dex ; standard HD 97603 = del Leo logL(A4V) = 1.545 dex ; exemplar 24 CVn = HD 118232 logL(A4V) = 1.57 dex ; Zorec12 median => adopt logL(A4V) = 1.128 dex [updated 9/24/2020] => adopt Mbol(A4V) = 1.920 mag [updated 9/24/2020] Mass(A4V) = 2.24 Msun ; Zorec12 median Mass(A4V) = 1.90 Msun ; EEM Mv vs. Mass fit for binaries (Mv=1.8) Mass(A4V) = 1.89 Msun ; EEM Teff vs. Mass fit for binaries (Teff=8200K) Mass(A4V) = 1.87 Msun ; Ekers18 ML calibration for logL=1.182 Mass(A4V) = 1.87 Msun ; EEM logL vs. Mass fit for binaries (logL=1.182) => adopt Mass(A4V) = 1.89 Msun [updated 12/29/2019] Rad(A4V) = 2.948 Rsun ; exemplar 24 CVn = HD 118232 Rad(A4V) = 2.496 Rsun ; standard HD 97603 = del Leo Rad(A4V) = 2.141 Rsun ; exemplar HD 37507 = HR 1937 = 49 Ori Rad(A4V) = 1.882 Rsun ; exemplar xi Vir = HD 102124 Rad(A4V) = 1.794 Rsun ; logL=1.128,Teff=8250K => adopt Rad(A4V) = 1.794 Rsun [updated 9/24/2020] # No standard Morgan65, MK73, MK78, Keenan85, GrayGarrison89, GrayAtlas, GrayNstars do not list A4V standards Skiff08 did not flag any stars as A4V standards. # Standard HD 97603 = del Leo = HR 4357 = Zosma A2V: Adams35 A3V: Maury1897,Chalonge52(BCD type),Woods55,Bidelman85(A3) *A4V: HoukStand,Roman49,JM53(stan),Palmer68,Cowley69(stan),Levato72,Levato78,Jaschek78,Loden83,Garcia89,Abt95,Levato78 A4IV: GrayGarrison89 A5IV(n): Gray03 A5V: Barry70(uv metals weak),Cuchiaro80(S2/68 spectra) The only A4V standard in JohnsonMorgan53. This star is a bit bluer than the A4V mean B-V (0.160) A4V, and more luminous. Note that two most "recent" expert classifications have it as lum class IV. Ursa Major stream star? V=2.56(HIP), V=2.56(TYC), V=2.560+-0.007(Mermilliod91), B-V=0.128+-0.014(Mermilliod91), B-V=0.128+-0.014(HIP). plx = 55.82+-0.25mas(HIP2). Teffs: 7881K(Boyajian13#1), 7889K(Boyajian13#2), 7974K(Stassun18), 8037K(Gray03), 8080K(Sokolov15), 8085K(Boyajian12), 8147K(Wu11), 8222K(Zorec12), 8297K(Boyajian13), 8309K(King03), 8449K(David15), 8891K(vanBelle09/erroneous Av=0.205), => = 8116K. logg=3.97+-0.14(David15), logg=3.84+-0.07(Wu11). Mv=1.29. tetLD = 1.328+-0.009mas(Boyajian13), fbol = (226.50+-0.229)e-8 erg/s/cm2(Boyajian13) => mbol = 2.615+-0.001(IIAU2015 scale). BCv = V - mbol = 2.560 - 2.615 = -0.055. vanBelle09 lists fbol = (299.60+-5.69)e-11 W/m2 => mbol 2.311+-0.021, but this assumes oddly high Av extinction (0.205+-0.014!) value for a star in the Local Bubble (d=18pc!) - this particular mbol (2.311+-0.021) leads to a very discrepent BCv estimate (BCv = +0.249). Luminosity: V=2.56, BCv=-0.02, plx=55.82+-0.25mas, Av=0.00 => Mbol = 1.27, logL = 1.386 => w/Teff=8116K => Rad = 2.496Rsun. # Deprecated Standard HD 11636 = Bet Ari = 6 Ari = HR 553 = GJ 80 = HIP 8903 = Sheratan A2: Ljunggren61 A4V: Abt85,GrayGarrison89,Garrison96,Abt95 A4: Olsen69 A5: Cannon,Cucchiaro78(A5m;S2/68 spectra) A5V: MK43,JM53,Jaschek64(all),Morgan65,Jaschek78,Garcia89 kA4hA5mA5Va: Gray03 (i.e. an A5Va!) A5IV: Maury1897,Barry70(A5IVb) Basically morphed from A5 under Morgan to A4 (Abt,Gray,Garrison), *despite* Morgan65 listing bet Ari as a "fundamental A5 classification standard" w/ del Cas i.e. it's a fundamental standard until someone comes along and changes it. Poor agreement on types. V=2.64(HIP), B-V(HIP)=0.165, plx=55.60+-0.58mas(HIP2), dMv=-0.53 (color is closer to Houk's mean A4V B-V color). Tomkin87 (1987AJ.....94.1664T) calls it a "double-lined eccentric spectroscopic binary", and says the star has mass ~1.9Msun and its companion is late F or G0 (~1.1 Msun), and estimates mass ratio of M2/M1=0.57. Tomkin87 estimates delta(V) ~ 2.8mag, in which case the V mag from HIP (2.64) would correspond to V(A)=2.72 and V(B)=5.52. For the primary then: V(A)=2.72, plx=55.60 => Mv=1.45. # Exemplars HD 37507 = HR 1937 = 49 Ori = HIP 26563 *A4V: Jaschek64(both; "SB"),Cowley69,GrayGarrison89(A4Vn) A4IV: Slettebak55,Abt65,Abt95 A2V: Houk99 Never previously considered a standard, but excellent exemplar as there is agreement in temp type by several expert classifiers. Spectroscopic binary in SB9, which references Abt65 - which reports it having a period of 445.74d, e=0.549 and K=28.6 km/s - apparently single-lined. Houk99 comments: "37507: HR 1937; 49 ORI; vSINi=185". Using the revised Hipparcos astrometry, I find the star to have Mv=1.52 or dMv = -0.23 (V=4.77; B-V=0.139; V-I=0.16+-0.02; plx=22.42mas). Stars B-V and V-I are only 0.02 bluer than the median B-V and V-I colors for the d<75 pc Hipparcos sample. Hence the color-mag data are consistent with a A4V. Negligibly reddened: E(B-V)=0.000(Kervella19,STILISM). plx=22.9587+-0.1110mas(GaiaEDR3), V=4.797+-0.011(Mermilliod91), B-V=0.139+-0.012(Mermilliod91), U-B=0.107+-0.008(Mermilliod91), Teffs: 8023K(GaiaDR2), 8041K(Paunzen06), 8102K(Blackwell98), 8140K(Stassun18), 8185K(Zorec12), 8305K(diBenedetto98), 8416K(David15), 8760K(Sokolov95) => = 8163K. logg=4.06+-0.14(David15). Luminosity: V=4.797, plx=22.9587mas, Av=0.00, BCv=-0.02 => Mv=1.60, Mbol=1.58, logL=1.263 => w/Teff=8163K => Rad=2.141Rsun. 24 CVn = HD 118232 = HR 5112 = HIP 66234 *A4V: Keenan41(A4),Slettebak55,Palmer68,Slettebak82,GrayGarrison89,Mora01(A4V shell) A5V: Cowley69,1978A&AS...35...75C(S2/68 spectra),Abt95 A5/A6Va: Barry70 Negligibly reddened: E(B-V)=0.005(Kervella19,STILISM) => Av~0.016. plx=18.09+-0.19mas(vanLeeuwen07), plx=17.5952+-0.1102mas(GaiaEDR3). V=4.68(HIP), V=4.687+-0.021(Mermilliod91), B-V=0.132+-0.005(HIP), B-V=0.129+-0.014(Mermilliod91), U-B=0.117+-0.015(Mermilliod91), V-I=0.10+-0.03(HIP). (B-V)o= 0.132 - 0.005 = 0.127. Teff: 7700K(Gebran19#1), 8110K(Stassun18), 8180K(Gebran19#2), 8285+-282K(David15), 8489K(Gebran19#2) => = 8180K. Luminosity: V=4.687, plx=17.5952mas, Av=0.016, BCv=-0.02 => Mv=0.90, Mbol=0.88, logL=1.545 => w/Teff=8180K => Rad=2.948Rsun. xi Vir = HD 102124 = HR 4515 = HIP 57328 *A4V: Cowley69,GrayGarrison89,Abt95 A5V: 1980A&AS...40..207C(S2/68 spectra) Negligibly reddened: E(B-V)=0.000(Kervella19,STILISM). V=4.838+-0.008(Mermilliod91), B-V=0.174(HIP), B-V=0.176+-0.005(Mermilliod91), U-B=0.091+-0.010(Mermilliod91), plx=26.73+-0.25mas(vanLeeuwen07), logL=1.077+-0.014(Stassun19). Teffs: 7862K(GaiaDR2), 7910+-130K(Masana06), 7993K(Stassun18), 8035+-93K(Zorec12),8172K(McDonald12), 8298+-282K(David15) => = 7993K. Rad=1.802+-0.053Rsun(Stassun19), Rad=1.815+-0.091Rsun(Kervella19). Luminosity: V=4.838, BCv=-0.02, Av=0.00, plx=26.73 => Mv=1.97, Mbol=1.95, logL=1.115 => w/Teff=7993K => Rad=1.882Rsun. # Other Stars HD 59037 = HR 2857 = 64 Gem (V=5.1) A4V: Cowley69,GrayGarrison89(A4Vn) A2.5V: Abt95 A6V: Osawa59 Never considered a standard by anyone. Not very good agreement among authors (although Cowley and GrayGarrison89 agree). Probably not a good candidate standard. Morgan65 did not classify any Hyads as A4V. While GrayGarrison89 did not list A4V standards, they did classify 9 stars as A4V or A4Vn. The brightest two examples of both were HD 37507 (= 49 Ori) and HD 59037 (= 64 Gem) (both A4Vn), and HD 11636 (iot Ari) and HD 184006 (iot^2 Cyg) (both A4V). Gray01/03/06 lists *1* nearby A4V dwarf (HIP 113368 = Fomalhaut). As Fomalhaut is *the* A3V anchor, I do not believe that its BVI colors are typical for A4V dwarf stars. HD 135384 = HR 5672 = BD+68 823 A2V: 1930MeUpp..48....1O *A4Vn: Palmer68,Abt95 A8Vn: Cowley69