A8V There appear to be no "classic" A8V standard stars, based on the survey of spectral standards reflected in this file, Pecaut12 adopts HD 158352 as an A8V standard. Standards: Pecaut12: HD 158352 - A8V Looking at the xHIP catalog (Hipparcos-based compilation by Anderson & Francis 2012 with other ancillary data), one finds that among the A/F dwarfs (lum class V) within 50pc from Gray01/Gray03/Gray06, there is a well-defined gap between 0.26 < B-V < 0.29. There are reports of various gaps amongst A/F (e.g.Bohm-Vitnse+70,D'Antona02). Remarkably, the star on the blue side is none other than HR 8799 (B-V=0.259+-0.010, Mv=2.99; SpT=F0+VkA5mA5 (lambda Boo)) and the star on the red side is HR 7848 = HIP 101612 (B-V=0.291+-0.012, Mv=2.53; SpT=F0V). Gray01/03/06 lists 5 A8V stars, with median HIP colors of: (A8V) = 0.230 (+-0.016 sem, +-0.038 stdev; N=5) (A8V) = 0.261 (+-0.015 sem, +-0.038 stdev; N=5) The brightest are HIP 105199 (V=2.5), HIP 32607 (V=3.3), and HIP 75695 (V=3.7). For A8V Hipparcos stars within 75pc, with parallax S/N > 8, and within 1 mag of the MS (N=4): (A8V) = 0.277 (+-0.035 sem, +-0.048 stdev; N=4) (A8V) = 0.315 (+-0.045 sem, +-0.062 stdev; N=4) (A8V) = 0.579 (+-0.063 sem, +-0.092 stdev; N=4) (A8V) = 0.639 (+-0.094 sem, +-0.136 stdev; N=4) (A8V) = 0.715 (+-0.092 sem, +-0.129 stdev; N=4) (A8V) = 0.064 (+-0.034 sem, +-0.053 stdev; N=4) (A8V) = 0.066 (+-0.036 sem, +-0.055 stdev; N=4) (A8V) = 0.287 (+-0.031 sem, +-0.045 stdev; N=4) (A8V) =-0.028 (+-0.009 sem, +-0.012 stdev; N=4) (A8V) = 0.993 (+-0.127 sem, +-0.178 stdev; N=4) (B-V)(A8V) = 0.277 ; d<60 pc SIMBAD (N=10) (B-V)(A8V) = 0.277 ; d<75 pc HIP A8V (N=4) (B-V)(A8V) = 0.27 ; Fitzgerald70 (B-V)(A8V) = 0.263 ; Morgan65 Hyad A8Vn HD 28024 (B-V)(A8V) = 0.257 ; BakisEker22 (B-V)(A8V) = 0.255 ; Morgan65 Hyad A8Vn HD 28910 (B-V)(A8V) = 0.25 ; Schmidt-Kaler82 (B-V)(A8V) = 0.240 ; smoothed trend SpT vs (B-V)o B9.5V-F3V 11/2021 (B-V)(A8V) = 0.237 ; color of A8V star HR 6507 (B-V)(A8V) = 0.230 ; Gray01/03/06 nearby A8V stars (N=5) (B-V)(A8V) = 0.23 ; Morgan71, KenyonHartmann95 => adopt (B-V)(A8V) = 0.25 *** [updated 9/24/2020; agrees well with Teff/B-V seq for A7V-F2V] => adopt (U-B)(A8V) = 0.082 => adopt (V-I)(A8V) = 0.288 => adopt (V-R)(A8V) = 0.140 => adopt (R-I)(A8V) = 0.148 => adopt (V-J)(A8V) = 0.508 => adopt (V-H)(A8V) = 0.584 => adopt (V-Ks)(A8V) = 0.626 => adopt (H-Ks)(A8V) = 0.042 => adopt (J-H)(A8V) = 0.075 (Bp-Rp)(A8V) = 0.2983 ; HD_24809 (Bp-Rp)(A8V) = 0.320 ; color trend for B-V=0.25 (Bp-Rp)(A8V) = 0.3400 ; rho_Tau (Bp-Rp)(A8V) = 0.3426 ; HD_158352 (Bp-Rp)(A8V) = 0.358 ; Evans18 trend for V-I=0.288 (Bp-Rp)(A8V) = 0.3645 ; HD_205924 (Bp-Rp)(A8V) = 0.4000 ; HD_50635 => adopt (Bp-Rp)(A8V)= 0.320 [updated 11/22/2020] (Bp-G)(A8V) = 0.117 ; color trend for B-V=0.25 (Bp-G)(A8V) = 0.1274 ; HD_24809 (Bp-G)(A8V) = 0.1568 ; HD_205924 (Bp-G)(A8V) = 0.1587 ; HD_158352 (Bp-G)(A8V) = 0.1806 ; rho_Tau (Bp-G)(A8V) = 0.2572 ; HD_50635 => adopt (Bp-G)(A8V) = 0.117 [updated 11/22/2020] (G-Rp)(A8V) = 0.1428 ; HD_50635 (G-Rp)(A8V) = 0.1594 ; rho_Tau (G-Rp)(A8V) = 0.1709 ; HD_24809 (G-Rp)(A8V) = 0.1839 ; HD_158352 (G-Rp)(A8V) = 0.2076 ; HD_205924 (G-Rp)(A8V) = 0.204 ; color trend for B-V=0.25 => adopt (G-Rp)(A8V) = 0.204 [updated 11/22/2020] Note that the V-IR colors seem too blue compared to the trends? (Ks-W1)(A8V) = 0.048 ; EEM trend for d<30pc for B-V=0.24 => adopt (Ks-W1)(A8V) = 0.048 [updated 12/29/2019] (G-V)(A8V) = -0.075 ; * alf Pic PM* A8VnkA6 (G-V)(A8V) = -0.056 ; * ups Tau dS* A8Vn (G-V)(A8V) = -0.053 ; * 67 Cnc PM* A8Vn (G-V)(A8V) = -0.046 ; polynomial fit f(B-V) (G-V)(A8V) = -0.045 ; * rho Tau dS* A8V (G-V)(A8V) = -0.043 ; V* CN Boo dS* A8V (G-V)(A8V) = -0.041 ; * 4 Cep * A8V (G-V)(A8V) = -0.041 ; HD 90132 PM* A8V (G-V)(A8V) = -0.030 ; fit for A dwarfs from Kervella19 corrected for E(B-V), eval for (V-Ks)=0.626 (G-V)(A8V) = -0.010 ; * eps Mon A A8V(n) (G-V)(A8V) = -0.005 ; * q Pup PM* A8V => adopt (G-V)(A8V) = -0.04 [updated 4/8/2022] (U-B)(A8V) = 0.09 ; Fitzgerald70 (U-B)(A8V) = 0.077 ; HIP d<75pc S/N>8 A8V N=10 (Mermilliod91 photometry) (g-r)(A8V) = 0.118 ; Jordi06 (V-R)=>(g-r) for V-R=0.140 (g-r)(A8V) = 0.029 ; Bilir05 (B-V)=>(g-r) for B-V=0.25 (g-r)(A8V) = 0.020 ; Covey07 interp A7V to F0V => adopt (g-r)(A8V) = 0.03 [updated 10/10/2020] Teff(A8V) = 7152 K ; Boyajian12 Teff(A8V) = 7444 K ; mean photometric Teff Teff(A8V) = 7482 K ; Zorec12 median Teff(A8V) = 7548 K ; EEM N=48 Teffs Teff(A8V) = 7580 K ; Schmidt-Kaler82 Teff(A8V) = 7590 K ; Teff trend maintaining intermed radius between A7V and A9V for logL=0.96 Teff(A8V) = 7605 K ; interp. (A7V-A9V) GrayCorbally09 Teff(A8V) = 7640 K ; exemplar rho Tau = HD 28910 (Hyad) Teff(A8V) = 7663 K ; HIP 40706, Stassun19/TICv8 Teff(A8V) = 7800 K ; median Teff for 4 A8V from Gray17 Teff(A8V) = 7762 K ; HIP 30419, Stassun19/TICv8 => adopt Teff(A8V) = 7590 K (logT = 3.880) [updated 9/26/2020] [EEM 9/26/2020: note this Teff maintains Teff/Rad continuity between A7V and A9V, and is consistent with other estimates] BCv(A8V) = 0.059 mag ; Balona94(Teff=7590K, BCv(5772K)=-0.085) BCv(A8V) = 0.052 mag ; Bertone04(ATLAS,Teff=7590K, BCv(5772K)=-0.085) BCv(A8V) = 0.030 mag ; Schmidt-Kaler82(BCv=-0.10 + 0.13 mag) BCv(A8V) = 0.028 mag ; Flower96(Teff=7590K, BCv(5772K)=-0.085) BCv(A8V) = 0.022 mag ; Masana06(Teff=7590K, BCv(5772K)=-0.085) BCv(A8V) = 0.02 mag ; EEM trend As BCv(A8V) = 0.002 mag ; Bessell98(ATLAS9,logg=4.5,Teff=7590K, BCv(5772K)=-0.085) BCv(A8V) = 0.000 mag ; Code76(Teff=7590K, BCv(5772K)=-0.085) BCv(A8V) = -0.005 mag ; Casagrande18(Teff=7500K,logg=4.5, BCv(5772K)=-0.085) => adopt BCv(A8V) = 0.02 [updated 9/26/2020; set so BCv(5772K)=-0.085] logg(A8V) = 4.2 ; median logg for 4 A8V from Gray17 Mv(A8V) = 2.4 mag ; interp. (A7V-A9V) GrayCorbally09 Mv(A8V) = 2.4 mag ; Schmidt-Kaler82 Mv(A8V) = 2.38 mag ; B/A/F dwarf sequence for B-V=0.25 Mv(A8V) = 2.32 mag ; linear B-V vs. Mv fit to d<50pc Gray01/03/06 dwarfs for B-V=2.32 Mv(A8V) = 2.28 mag ; interp BAF dwarf seq for B-V=0.24 Mv(A8V) = 2.27 mag ; Wright05(B-V=0.25mag) Mv(A8V) = 2.18 mag ; d<60pc Mv(B-V=0.255) Mv(A8V) = 1.98 mag ; median Mv for A9V calc using Kervella19 HIP & Gaia DR2 (d<100pc) Mv(A8V) = 1.92 mag ; Wegner07 Mv(A8V) = 1.786 mag ; d<60pc median A8V N=10 Mv(A8V) = 1.41 mag ; pri. stan. HD 158352 = HR 6507 Mv(A8V) = 1.22 mag ; exemplar rho Tau = HD 28910 => adopt Mv(A8V) = 2.32 mag [updated 9/26/2020] => adopt M_G(A8V) = 2.27 mag [updated 12/10/2020] (Mv=2.32, G-V=-0.05) => adopt M_Ks(A8V) = 1.694 mag [updated 12/30/2020] (Mv=2.32, V-Ks=0.626) [EEM: where are the 'faint' A8V stars? The exemplars all seem bright.] logL(A8V) = 0.938 dex ; Mv=2.38, BCv=0.02 => Mbol = 2.400 logL(A8V) = 0.960 dex ; Mv=2.32, BCv=0.02 => Mbol = 2.340 logL(A8V) = 1.276 dex ; Zorec12 median => adopt logL(A8V) = 0.960 dex [updated 9/26/2020] => adopt Mbol(A8V) = 2.340 mag [updated 9/26/2020] Mass(A8V) = 1.92 Msun ; Zorec12 median Mass(A8V) = 1.854+-0.016 Msun ; Eclipsing binary RS Cha A (pre-MS, Torres10) Mass(A8V) = 1.817+-0.018 Msun ; Eclipsing binary RS Cha B (pre-MS, Torres10) Mass(A8V) = 1.68 Msun ; Ekers15 ML calibration for logL=0.97 Mass(A8V) = 1.67 Msun ; EEM Mv vs. Mass fit for binaries (Mv=2.29) Mass(A8V) = 1.67 Msun ; EEM Teff vs. Mass fit for binaries (Teff=7500K) Mass(A8V) = 1.66 Msun ; EEM logL vs. Mass fit for binaries (logL=0.96) Mass(A8V) = 1.561+-0.011 Msun ; Eclipsing binary PV Pup A (Torres10) Mass(A8V) = 1.550+-0.013 Msun ; Eclipsing binary PV Pup B (Torres10) Mass(A8V) = 1.5001+-0.0097 Msun ; Eclipsing binary TZ Men B (Torres10) => adopt Mass(A8V) = 1.67 Msun [updated 9/16/2019] Rad(A8V) = 2.623 Rsun ; HIP 30419, Stassun19/TICv8 Rad(A8V) = 1.844 Rsun ; HIP 40706, Stassun19/TICv8 Rad(A8V) = 1.782 Rsun ; smoothed SpT vs Rad trend A/F dwarfs Rad(A8V) = 1.747 Rsun ; logL=0.960, Teff=7590K Rad(A8V) = 1.7445 Rsun ; interp A7V-F2V for logT=3.875 Rad(A8V) = 1.740 Rsun ; logL=0.936 ,Teff=7500K => adopt Rad(A8V) = 1.747 Rsun [updated 9/26/2020] [EEM: note this radius fits in trend for late As: # No Standard MK43, JM53, Morgan65, Cowley69, MK73, Cowley74, Houk75, Cowley76, MK78, Keenan85, GrayNstars do not provide an A8V standard Skiff08 did not flag any stars as A8V MK standards. I searched Skiff08 MK catalog to find stars with 3 or more "A8V" classifications: HD 28024 = HR 1392 (3 refs; V=4.3; Hyad; no Teffs) HD 158352 = HR 6507 (3 refs; V=5.4; Teff from Masana06) GrayGarrison89 classified A3-A7, but listed some A8 stars. The only two non-standard dwarfs were HD 96113 (A8V+) and HD 205924 (A8Vn). # Primary Standard HD 158352 = HR 6507 = HIP 85537 *A8V: Cowley69,Abt95,Mora01(A8Vp),Pecaut12(stan). A5: Cannon Historically there were no A8V standard in the literature (e.g. papers and atlases by Morgan, Gray, Garrison, etc.). Houk adopts A8V by cites "SIMBAD type listed; vsini=190 [km/s]." Vmag=5.44(HIP), V=5.418+-0.013(Mermilliod91), V=5.42(Hauck97), B-V=0.237(HIP), B-V=0.227+-0.006(Mermilliod91), plx=15.86+-0.69 mas (HIP), plx = 15.7570+-0.1611mas(GaiaDR2). Shell & Vega-type star. Based on the literature search shown here, Pecaut12 adopts this star as the best available A8V standard. Pecaut12 confirmed that the spectrum of HD 158352 is intermediate between A7V and F0V MK standards, and slightly hotter than the adopted A9V standard HD 73450 (BS Cnc). WDS lists a nonphysical companion (mag2=9.75) at sep=46.8". VSX liists it as a variable with amplitude 0.01 mag and period 0.0756d - presumably delta Scuti? No evidence of unresolved binarity, but star is ~0.7 mag above MS (so I'm wondering if might be an ~equal mass binary?). Teffs: 7430+-77K(Masana06), 7482+-52K(Zorec12), 7624+-259K(David15) => = 7624K. logg=3.82+-0.14(David15). Mv=1.405+-0.026. David15 estimates age of ~1.02 Gyr and mass 1.77 Msun. # Exemplar rho Tau = HD 28910 = Cl* Melotte 25 Rg 353 = HR 1444 (Hyad) F1: 1920AN....211..289K F0V: 1940ApJ....91..256T,Slettebak55,Ljunggren61(F0) A9V: Barry70(uv metals wk),GrayGarrison89 *A8V: Morgan65(A8Vn),Cowley69 A7V: Abt95 A7III: 1980A&AS...40..207C A5V: Adams35,Ramberg41(A5) plx= 22.6703+-0.8800mas(GaiaDR2), plx=20.61+-0.57mas(HIP2). V=4.65(HIP), B-V=0.255+-0.007(HIP). Mv=1.22(V from HIP, plx from HIP2). PASTEL: = 7640K(N=3), logg=4.02+-0.20(Gebran10), [Fe/H]=0.12+-0.30(Gebran10). # Others HD 28024 = ups Tau = HR 1392 A3V: Adams35 A7.5V: Palmer68 A8Vn: Morgan65,Cowley69,Abt95 A9IV-n: GrayGarrison89 F0V: 1940ApJ....91..256T F0III-IV: Slettebak55 F0III: Cucchiaro80 One of two Hyads classified A8V by Morgan65 (along with rho Tau = HD 28910). B-V(HIP)=0.263 (exactly halfway between A7 & F0), plx = 21 mas (HIP). Good agreement on type from Morgan, Cowley & Abt, but GrayGarrison call A9. HD 28910 = rho Tau = Cl* Melotte 25 Rg 353 = HR 1444 (Hyad) F1: 1920AN....211..289K F0V: 1940ApJ....91..256T,Slettebak55,Ljunggren61(F0) A9V: Barry70(uv metals wk),GrayGarrison89 A8V: Morgan65(A8Vn),Cowley69 A7V: Abt95 A7III: 1980A&AS...40..207C A5V: Adams35,Ramberg41(A5) One of two Hyads classified A8V by Morgan65 (along with ups Tau = HD 28024), but both classified A9V by GrayGarrison89. plx= 22.6703+-0.8800mas(GaiaDR2), plx=20.61+-0.57mas(HIP2). V=4.65(HIP), B-V=0.255+-0.007(HIP). Mv=1.22(V from HIP, plx from HIP2). PASTEL: = 7640K(N=3), logg=4.02+-0.20(Gebran10), [Fe/H]=0.12+-0.30(Gebran10). HD 203280 = alf Cep = HIP 105199 (from A7V README file) A5: Cannon A7V: MK43(stan),Palmer68 A7V-IV: Cowley69,Jaschek78 A7:Vn: Abt95 A8IV: Barry70 A8Vn: Gray03 Jaschek64 lists mix of (A7V, V-IV, & IV-V) B-V(HIP)=0.257, dMv=-0.73, d=15pc. Subtypes shifted a bit A7=>A8 and it appears to be slightly evolved Probably best considered a "A8IV-V", and probably not the best standard HD 4399 = SB 312 = [PS72] 253 A6: Phillip72 *A8V: Lu92,Chen03 A9V: Bond71,Houk82, F0: Slettebak71 Near south Galactic pole. V=9.68(Tycho), V=9.640(Mermilliod910, B-V=0.264+-0.037(Tycho), B-V=0.280(Mermilliod91), U-B=0.030(Mermilliod91). Av=0.03(Guarino92), E(B-V)=0.024(Bianchi11). HD 50635 = 38 Gem = HR 2564 *A8V: Wilson52,Abt95 A9V: GrayGarrison89 Several other classifications between A7V and F0. G4V companion 7" away. Morgan65 classified two Hyads as A8Vn: HD 28024 & HD 28910. They have B-V colors of 0.263 (HD 28024) and 0.255 (HD 28910) Cowley69 did not list an A8V standard, but classified 26 stars as A8V or variant (brightest three are HR 1392, HR 1394, HR 1444) Cowley76 did not list an A8V standard, but classified two bright stars as A8V: HR 1388 (A8Vn) and HR 8270 (A8Vn) HD 205924 = HR 8270 A2V: Adams35 *A8Vn: GrayGarrison89,Cowley76,Abt95(A8:Vn) A9IV-V:n: Cowley74 A pec: Cucchiaro78 HD 24809 = HR 1223 = NGC 1499 +34 38 A5III: 1985CBVMS.C......0V A7V: Abt95 *A8V: Cowley69,1981PASP...93..735P HD 29606 = HR 1486 A7IV: Cowley69 *A8V: Cowley67,Abt95