FF5.5V There are no F5.5V standards, but one occasionally sees nearby dwarf stars typed as F5.5V (mostly by Gray03 & Gray06). If one looks at the stars classified F5.5V within 50pc in xHIP (mostly classified by Gray06 within one by Gray03 and one random from SIMBAD), it is apparent that most of the stars classified F5.5V end up being metal poor. Perhaps this was due to some quirk in the choice of standards. For whatever reason, simply looking at the mean/median properties of F5.5V for nearby dwarfs wont give a useful value for solar composition. (B-V)(F5.5V) = 0.489 ; HIP_73850 F5.5V [Fe/H]=-0.01 (B-V)(F6V) = 0.484 (B-V)(F5.5V) = 0.480 ; HIP_56445 F5.5V [Fe/H]=+0.03 (B-V)(F5.5V) = 0.48 ; HIP 103673 Gray06 F5.5V, metal-poor (B-V)(F5.5V) = 0.479 ; HIP_84489 F5.5V [Fe/H]=-0.13 (B-V)(F5.5V) = 0.476 ; xHIP F5.5V d<50pc trend for [Fe/H]=0.00 (B-V)(F5.5V) = 0.470 ; HIP_20781 F5.5V [Fe/H]=-0.14 (B-V)(F5.5V) = 0.469 ; HIP_66139 F5.5V [Fe/H]=-0.14 (B-V)(F5.5V) = 0.460 ; HIP_64407 F5.5V [Fe/H]=-0.12 (B-V)(F5.5V) = 0.457 ; HIP_20630 F5.5V [Fe/H]=+0.00 (B-V)(F5.5V) = 0.452 ; exemplar HR 4455 (B-V)(F5V) = 0.44 => adopt (B-V)(F5.5V) = 0.475 [updated 9/26/2020] Teff(F5V) = 6570K Teff(F5.5V) = 6465K ; halfway F5V-F6V Teff(F5.5V) = 6460K ; exemplar HR 4455 = HD 100563 Teff(F5.5V) = 6423K ; PASTEL Teff vs. [Fe/H] trend for Gray03/06 F5.5V (see below) Teff(F5.5V) = 6415K ; Gray03/06 F5.5Vs median from TIC9/Stassun19 (N=13) Teff(F5.5V) = 6408K ; see below, trend for solar metallicity Teff(F6V) = 6360K ; adopted => adopt Teff(F5.5V) = 6410 K (logT=3.807) [updated 9/26/2020] [EEM 9/26/2020: 6410K consistent with smooth B-V vs. Teff trend among F dwarfs] => adopt (U-B)(F5.5V) = -0.027 => adopt (B-V)(F5.5V) = 0.462 => adopt (Bt-Vt)(F5.5V) = 0.481 => adopt (V-Ic)(F5.5V) = 0.532 => adopt (V-Rc)(F5.5V) = 0.265 => adopt (Rc-Ic)(F5.5V) = 0.267 => adopt (V-J)(F5.5V) = 0.894 => adopt (V-H)(F5.5V) = 1.081 => adopt (V-Ks)(F5.5V) = 1.136 => adopt (H-Ks)(F5.5V) = 0.055 => adopt (J-H)(F5.5V) = 0.186 => adopt (Ks-W1)(F5.5V) = 0.028 => adopt (V-Hp)(F5.5V) = -0.103 => adopt (W1-W2)(F5.5V) = -0.032 => adopt (W1-W3)(F5.5V) = -0.045 => adopt (W1-W4)(F5.5V) = -0.010 => adopt (Bp-Rp)(F5.5V) = 0.614 => adopt (Bp-G)(F5.5V) = 0.238 => adopt (G-Rp)(F5.5V) = 0.378 (G-V)(F5.5V) = -0.136 ; trend for screened late F dwarfs for B-V=0.475 (see 10/24/2020 notes in F5V.txt) (g-r)(F5.5V) = 0.318 ; Jordi06 (V-R)=>(g-r) for V-R=0.265 (g-r)(F5.5V) = 0.282 ; Bilir05 (B-V)=>(g-r) for B-V=0.475 (g-r)(F5.5V) = 0.27 ; Covey07 => adopt (g-r)(F5.5V) = 0.28 [updated 10/10/2020] BCv(F5.5V) = -0.047 ; EEM fit to Casagrande06/08/10(Teff=6450K, set so BCv(5772K)=-0.085 BCv(F5.5V) = -0.033 ; Code76(Teff=6450K, set so BCv(5772K)=-0.085) BCv(F5.5V) = -0.026 ; Casagrande18(logg=4.5,Teff=6450K, set so BCv(5772K)=-0.085) BCv(F5.5V) = -0.022 ; Bessell98(Teff=6450K,logg=4.5, set so BCv(5772K)=-0.085) BCv(F5.5V) = -0.021 ; Masana06(Teff=6450K, set so BCv(5772K)=-0.085) BCv(F5.5V) = -0.001 ; Flower96(Teff=6450K, set so BCv(5772K)=-0.085) BCv(F5.5V) = +0.029 ; Bertone94(ATLAS,Teff=6450K) BCv(F5.5V) = +0.039 ; Balona94(Teff=6450K, set so BCv(5772K)=-0.085) => adopt BCv(F5.5V) = -0.025 [updated 9/20/2019, adjusted so that BCv(5772K)=-0.085] Mv(F5.5V) = 3.41 ; F dwarf trend standards/exemplars Mv(F5.5V) = 3.53 ; d<60pc SIMBAD F5.5V (N=12) Mv(F5.5V) = 3.53 ; linear fit to Gray01/03/06 dwarf sequence (d<50pc) for B-V=0.46 Mv(F5.5V) = 3.52 ; Gray01/03/06 dwarfs, xHIP B-V/Mv, Gaspar16 |[Fe/H]|<0.05 "solar": fit for B-V=0.46 Mv(F5.5V) = 3.54 ; Wright04 MS for B-V=0.46 Mv(F5.5V) = 3.61 ; xHIP F5.5V d<50pc trend for [Fe/H]=0.0 (see below) Mv(F5.5V) = 3.61 ; EEM fit to FGK d<25pc for B-V=0.46 Mv(F5.5V) = 3.62 ; exemplar HR 4455 = HD 100563 => adopt Mv(F5.5V) = 3.53 [updated 9/26/2020] => adopt M_G(F5.5V) = 3.394 [updated 12/10/2020] (Mv=3.53, G-V=-0.136) => adopt M_Ks(F5.5V) = 2.394 [updated 12/30/2020] (Mv=3.53, V-Ks=1.136) logL(F5.5V) = 0.466 dex; Mv=3.60, BCv=-0.025 => Mbol = 3.575 => adopt logL(F5.5V) = 0.466 dex [update 9/20/2019] => adopt Mbol(F5.5V) = 3.575 mag [update 9/20/2019] Rad(F5.5V) = 1.432 Rsun ; Stassun/TICv8 Rads for smoothed trend for Gray03/06 FVs (Teff=6450K) Rad(F5.5V) = 1.416 Rsun ; Gray03/06 F5.5Vs median from TIC9/Stassun19 (N=11) Rad(F5.5V) = 1.369 Rsun ; Teff=6450K, logL=0.466 => adopt Rad(F5.5V) = 1.369 Rsun [updated 9/26/2019] # Exemplar HR 4455 = HD 100563 (V=5.8; J1134+0303) F4V: Cowley76 F5V: Adams35 *F5.5V: Gray06 F6V: Cowley79 F6+V: Gray03 F7V: Harlan74 The only one of the Gray06 F5.5V stars with near-solar metallicity ([Fe/H] = 0.12 (Boesgaard86), -0.02+-0.10 (Chen00), 0.06+-0.08 (Sitnova15)). plx = 36.9527+-0.0817 mas (GaiaDR2). V=5.778+-0.017(Mermilliod91), B-V=0.452+-0.017(Mermilliod91), U-B=0.005+-0.009(Mermilliod91). Mv = 3.616+-0.018(HIP,GaiaDR2). PASTEL values: = 6460K(N=5), =4.31(N=3), [Fe/H]=+0.06(N=3). HD 43042 = 71 Ori = HR 2220 F5IV: Maury1897,Cowley76 *F5.5IV-V: Gray03 F6V: Roman55(lines strong),Harlan69,Bidelman85 F6IV/V: Adams35 # Other Stars HD 199623 = HR 8027 F5IV-V: Malaroda75 F5/6V: Houk78 *F5.5V: Gray06 F6V: 1953AnHar.119....1H,DeVaucouleurs57 F8Vm-1: Gray89 F8V: Evans66 PASTEL compendium: <[Fe/H]> = -0.37 (N=3), Teff=6260K(N=4), logg=4.27(N=3) # NOTES For 22 published Teffs from PASTEL compendium, one finds following trend for F5.5V stars from Gray03 and Gray06: Teff = 6408K + 315*[Fe/H] (rms = 62K) F5.5V stars within 50pc in xHIP: [Fe/H] B-V eB-V Mv HIP# SpT 0.03 0.480 0.005 3.59 56445 F5.5V 0.00 0.457 0.004 3.55 20630 F5.5V -0.01 0.489 0.008 3.75 73850 F5.5V -0.12 0.460 0.000 2.39 64407 F5.5V -0.13 0.479 0.007 3.60 84489 F5.5V -0.14 0.469 0.006 3.63 66139 F5.5V -0.14 0.470 0.006 3.50 20781 F5.5V -0.18 0.460 0.017 3.13 32765 F5.5V -0.24 0.438 0.005 3.76 33705 F5.5V_Fe-0.7 CH-0.4 -0.29 0.455 0.026 3.08 23941 F5.5V_Fe-0.7 -0.33 0.480 0.017 3.52 103673 F5.5V -0.35 0.429 0.005 3.49 32500 F5.5V_Fe-1.0 CH-0.6 Trends: (B-V) = 0.4759 + 0.07631*[Fe/H] (rms=0.016) Mv = 3.6093 + 0.61915*[Fe/H] (rms=0.214;clipped 1) Metallicity & Teff data from PASTEL for Gray03/06 F5.5V stars #[Fe/H] Teff ID_ ref -0.500 6296 HD_33256_ 2007A&A...465..271R -0.490 6300 HD_33256_ 1989A&A...208..171G -0.430 6300 HD_33256_ 1991A&A...244..425Z -0.320 6397 HD_33256_ 1996A&A...314..191G -0.340 6400 HD_33256_ 1992ApJ...387..170F -0.240 6406 HD_33256_ 2014A&A...562A..71B -0.330 6421 HD_33256_ 2013ApJ...764...78R -0.280 6421 HD_33256_ 2017AJ....153...21L -0.300 6427 HD_33256_ 2003A&A...410..527B -0.270 6433 HD_33256_ 2018AJ....155..111L -0.300 6442 HD_33256_ 1993A&A...275..101E -0.150 6347 HD_114378_ 2004A&A...420..183A -0.230 6365 HD_114378_ 2005AJ....129.1063L -0.230 6365 HD_114378_ 2006AJ....131.3069L -0.090 6391 HD_114378_ 2017AJ....153...21L -0.230 6406 HD_114378_ 2013ApJ...764...78R -0.240 6386 HD_50223_ 1996A&A...314..191G -0.200 6460 HD_50223_ 1993A&A...275..101E 0.120 6380 HD_100563_ 1986ApJ...303..724B -0.020 6423 HD_100563_ 2000A&AS..141..491C 0.060 6460 HD_100563_ 2015ApJ...808..148S 0.150 6516 HD_100563_ 2018AJ....155..111L 0.150 6538 HD_100563_ 2017AJ....153...21L -0.030 4941 HD_114642_ 1966AnAp...29..593H -0.240 6296 HD_114642_ 1990ApJ...354..310B -0.200 6301 HD_114642_ 1996A&A...314..191G -0.210 6375 HD_114642_ 2013ApJ...764...78R -0.170 6375 HD_114642_ 1993A&A...275..101E -0.120 6434 HD_114642_ 2005PASJ...57...27T -0.150 6462 HD_114642_ 1984A&A...136...65A 0.120 6425 HD_133469_ 2018AJ....155..111L -0.110 6265 HD_155974_ 1999A&A...348..487R -0.170 6275 HD_155974_ 2005ApJS..159..141V -0.200 6282 HD_155974_ 2006MNRAS.370..163B -0.190 6309 HD_155974_ 1990ApJ...354..310B -0.320 6246 HD_199623_ 2004A&A...425..187T -0.370 6246 HD_199623_ 1996A&A...314..191G -0.370 6285 HD_199623_ 1993A&A...275..101E Trend: Teff = 6423K + 242*[Fe/H] (rms=64K)