MMM5.5V Kirkpatrick(in GrayCorbally09) calls GJ 1245AC as the primary M5.5V standard. But the star is a 0.1" binary (delta(V)=2.5 mag), and Reid04 calls component C a M7.0V. G 208-44AB = GJ 1245AC has remained a M5.5V standard, but recent authors (Kirkpatrick) consider G 208-45 an M6V. Note that K91 does not list any M5.5V standards from Boeshaar76. KeenanMcNeil76 standard: G208-44 (=GJ 1245AC) - M5.5eV Keenan80 standard: G208-44 (=GJ 1245AC) - M5.5Ve Keenan83 standard: G208-44 (=GJ 1245AC) - M5.5Ve Boeshaar85 standards: G208-44AB (=GJ 1245AC) - M5.5V G208-45 (=GJ 1245B) - M5.5V Keenan85 standard: G208-44 - M5.5V Keenan88 standard: G208-44 (=GJ 1245AC) - M5.5Ve Keenan89 standard: G208-44 (=GJ 1245AC) - M5.5Ve Kirkpatrick91 standards: G208-44 (=GJ 1245AC) (pri. standard) GJ 65A - M5.5V (pri. standard) GJ 4037 (=LHS 3339) - M5.5V (sec. standard) Henry02 standards: GJ 65A - M5.5V GJ 412B - M5.5V GJ 473AB - M5.5VJ (joint, binary) GJ 551 (=Proxima Cen) - M5.5V GJ 905 - M5.5V GJ 1002 - M5.5V GJ 1061 - M5.5V GJ 1116AB - M5.5VJ (joint, binary) GJ 1245AC - M5.5VJ (joint, binary) GJ 1286 - M5.5V GJ 2005ABCD - M5.5VJ (joint, multiple) According to RECONS list, Prox Cen (GJ 551; J1429-6240) is the closest M5.5V, followed by GJ 65A (J0139-1757), GJ 473B (J1233+0901), GJ 1002 (J00006-0732). B-V(M5.5V) = 1.99 ; ter. stan. GJ412B B-V(M5.5V) = 1.978 ; sec. stan. GJ1002 B-V(M5.5V) = 1.95 ; ter. stan. GJ1286 B-V(M5.5V) = 1.94 ; Bessell91 "old disk" B-V(M5.5V) = 1.915 ; ter. stan. GJ905 B-V(M5.5V) = 1.900 ; pri. stan. GJ1245AC (G208-44) B-V(M5.5V) = 1.900 ; sec. stan. GJ1061 B-V(M5.5V) = 1.886 ; sec. stan. GJ551 (Proxima Centauri) B-V(M5.5V) = 1.846 ; G12-43 (Landolt92) B-V(M5.5V) = 1.843 ; ter. stan. GJ473AB => adopt (B-V)(M5.5V) = 1.91 U-B(M5.5V) = 1.752+-0.128 ; sec. stan. GJ1002 U-B(M5.5V) = 1.52 ; sec. stan. GJ1061 U-B(M5.5V) = 1.48 ; ter. stan. GJ905 U-B(M5.5V) = 1.270+-0.045 ; ter. stan. GJ473AB U-B(M5.5V) = 1.253 ; U-B vs. B-V trend for Landolt09 stans for B-V=1.91 (few objects) U-B(M5.5V) = 1.18 ; ter. stan. GJ 412B U-B(M5.5V) = 1.085 ; G12-43 (Landolt92) => adopt (U-B)(M5.5V) = 1.3 V-R(M5.5V) = 1.69 ; Bessell91 "old disk" R-I(M5.5V) = 2.06 ; Bessell91 "old disk" R-I(M5.5V) = 1.944 ; G12-43 (Landolt92) V-I(M5.5V) = 3.75 ; Bessell91 "old disk" V-I(M5.5V) = 3.65 ; Hawley96 V-I(M5.5V) = 3.479 ; G12-43 (Landolt92) V-K(M5.5V) = 6.71 ; Bessell91 "old disk" V-K(M5.5V) = 6.68 ; sec. stan. GJ 551 (Proxima Centauri) V-Ks(M5.5V) = 6.621 ; halfway between M5V(5.942) and M6V(7.30) V-Ks(M5.5V) = 6.561 ; ter. stan. GJ 412B V-Ks(M5.5V) = 6.556 ; pri. stan. G 208-44 V-Ks(M5.5V) = 6.517 ; ter. stan. GJ 1286 V-Ks(M5.5V) = 6.480 ; sec. stan. GJ 1061 V-Ks(M5.5V) = 6.413 ; ter. stan. GJ 473AB V-K(M5.5V) = 6.4 ; Hawley96 V-Ks(M5.5V) = 6.365 ; ter. stan. GJ 905 V-Ks(M5.5V) = 6.320 ; sec. stan. GJ 1002 => adopt (V-Ks)(M5.5V) = 6.50 *** => adopt (B-V)(M5.5V) = 1.948 => adopt (V-I)(M5.5V) = 3.664 => adopt (V-R)(M5.5V) = 1.656 => adopt (R-I)(M5.5V) = 2.007 => adopt (V-J)(M5.5V) = 5.583 => adopt (V-H)(M5.5V) = 6.171 => adopt (H-Ks)(M5.5V) = 0.329 => adopt (J-H)(M5.5V) = 0.588 (Bp-Rp)(M5.5V) = 3.5311 ; GJ_905 (Bp-Rp)(M5.5V) = 3.6815 ; GJ_1061 (Bp-Rp)(M5.5V) = 3.6914 ; GJ_1002 (Bp-Rp)(M5.5V) = 3.7117 ; GJ_1245AC (Bp-Rp)(M5.5V) = 3.7206 ; GJ_1286 (Bp-Rp)(M5.5V) = 3.7965 ; GJ_551 => adopt (Bp-Rp)(M5.5V) = 3.70 [updated 12/10/2018] (G-Rp)(M5.5V) = 1.3371 ; GJ_905 (G-Rp)(M5.5V) = 1.3670 ; GJ_1061 (G-Rp)(M5.5V) = 1.3672 ; GJ_551 (G-Rp)(M5.5V) = 1.3758 ; GJ_1002 (G-Rp)(M5.5V) = 1.3871 ; GJ_1286 (G-Rp)(M5.5V) = 1.4311 ; GJ_1245AC => adopt (G-Rp)(M5.5V) = 1.37 [updated 12/10/2018] (Bp-G)(M5.5V) = 2.1940 ; GJ_905 (Bp-G)(M5.5V) = 2.2806 ; GJ_1245AC (Bp-G)(M5.5V) = 2.3145 ; GJ_1061 (Bp-G)(M5.5V) = 2.3157 ; GJ_1002 (Bp-G)(M5.5V) = 2.3335 ; GJ_1286 (Bp-G)(M5.5V) = 2.4293 ; GJ_551 => adopt (Bp-G)(M5.5V) = 2.33 [updated 12/10/2018, adjusted a bit to fit better determined Bp-Gp, G-Rp] (G-V)(M5.5V) = -2.1574 ; GJ_551 (G-V)(M5.5V) = -2.0598 ; GJ_1286 (G-V)(M5.5V) = -2.0411 ; GJ_1061 (G-V)(M5.5V) = -1.9786 ; GJ_1002 (G-V)(M5.5V) = -1.9437 ; GJ_1245AC (G-V)(M5.5V) = -1.9285 ; GJ_905 => adopt (G-V)(M5.5V) = -2.01 [updated 12/10/2018] Teff(M5.5V) = 2800 K ; Rajpurohit13(N=4) Teff(M5.5V) = 2890 K ; pri. stan. GJ 1245AC/G 208-44 Teff(M5.5V) = 2900 K ; Bessell91 "old disk" Teff(M5.5V) = 2920 K ; sec. stan. GJ 551 (Proxima Centauri) Teff(M5.5V) = 2999 K ; sec. stan. GJ 1061 Teff(M5.5V) = 3000 K ; ter. stan. GJ 473AB Teff(M5.5V) = 3000 K ; ter. stan. GJ 65A Teff(M5.5V) = 3006 K ; ter. stan. GJ 1286 Teff(M5.5V) = 3043 K ; ter. stan. GJ 905 Teff(M5.5V) = 3067 K ; Rajpurohit18 (mean for N=6 M5.5Vs) Teff(M5.5V) = 3140 K ; sec. stan. GJ 1002 => adopt Teff(M5.5V) = 3000 K (logT = 3.477) [last updated 11/13/2018] BCv(M5.5V) = -4.24 ; deprecated standard LHS 3339 (derived using Dahn02) BCv(M5.5V) = -3.831 +- 0.024 ; GJ 551 = Proxima Cen (Pecaut13) BCv(M5.5V) = -3.83 ; Bessell91("old disk"; BCv = (V-I)-BC_I) BCv(M5.5V) = -3.780 +- 0.028 ; GJ 551 = Proxima Cen (VOSA SED fit, see below) BCv(M5.5V) = -3.77 ; deprecated standard GJ 65AB (Leggett96) BCv(M5.5V) = -3.75 ; sec. stan. GJ 551 = Proxima Cen (calc. using Ribas17) BCv(M5.5V) = -3.63 ; BC_K=2.87,V-Ks=6.50 BCv(M5.5V) = -3.580 ; Mann15(V-J=5.583) => adopt BCv(M5.5V) = -3.63 [updated 3/8/2018; from BC_K=2.87,V-K=6.50] BC_K(M5.5V) = 2.977 ; sec. stan. GJ 551 = Prox Cen (calc. using Ribas17) BC_K(M5.5V) = 2.898 ; Mann15(V-J=5.583) BC_K(M5.5V) = 2.867 ; smoothed trend over M0V-M9V for M5.5V BC_K(M5.5V) = 2.866 ; deprecated stan. GJ 65AB (Leggett96) BC_K(M5.5V) = 2.865 ; deprecated standard LHS 3339 (derived using Dahn02) BC_K(M5.5V) = 2.841 ; GJ 551 = Proxima Cen (VOSA SED fit, see below; assume V-Ks=6.621 for mean M5.5V) => adopt BC_K(M5.5V) = 2.87 [updated 3/8/2018] Mv(M5.5V) = 15.543 ; sec. stan. Proxima Centauri Mv(M5.5V) = 15.485 ; Dieterich14 calibration for V-Ks=6.50 Mv(M5.5V) = 15.460 ; JohnsonApps09 calibration for V-Ks=6.50 Mv(M5.5V) = 15.40 ; ter. stan. GJ 1286 Mv(M5.5V) = 15.372 ; Henry04 calibration for V-Ks=6.50 Mv(M5.5V) = 15.28 ; EEM calibration for V-Ks=6.50 Mv(M5.5V) = 15.193 ; Finch14 calibration for V-Ks=6.50 Mv(M5.5V) = 15.18 ; sec. stan. GJ 1002 Mv(M5.5V) = 15.12 ; pri. stan. GJ 1245AC Mv(M5.5V) = 14.80 ; ter. stan. GJ 905 => adopt Mv(M5.5V) = 15.28 [updated 3/8/2018] M_Ks(M5.5V) = 8.985 ; Dieterich14 calibration for V-Ks=6.50 M_Ks(M5.5V) = 8.960 ; JohnsonApps09 calibration for V-Ks=6.50 M_Ks(M5.5V) = 8.872 ; Henry04 calibration for V-Ks=6.50 M_Ks(M5.5V) = 8.779 ; EEM calibration for V-Ks=6.50 M_Ks(M5.5V) = 8.693 ; Finch14 calibration for V-Ks=6.50 => adopt M_Ks(M5.5V) = 8.78 [Mv=15.28,V-K=6.50; last updated 3/8/2018] logL(M5.5V) = -2.54 ; deprecated standard GJ 65AB (Leggett96,unresolved) logL(M5.5V) = -2.81 ; sec. stan. Proxima Centauri logL(M5.5V) = -2.856 ; Mv=15.48, BCv=-3.60, Mbol=11.880 => adopt logL(M5.5V) = -2.86 [last updated 9/29/2017] => adopt Mbol(M5.5V) = 11.88 [last updated 9/29/2017] Rad(M5.5V) = 0.138 Rsun ; Teff=3000K, logL=-2.86 Rad(M5.5V) = 0.1410 +- 0.0070 Rsun ; Boyajian12b (N=1) Rad(M5.5V) = 0.165 +- 0.006 Rsun ; BL Cet (GJ 65B) (Kervella16) [inflated/activity] => adopt Rad(M5.5V) = 0.138 Rsun [last updated 9/29/2017] Mass(M5.5V) = 0.143 Msun ; Wolf 424A (Torres99) Mass(M5.5V) = 0.131 Msun ; Wolf 424B (Torres99) Mass(M5.5V) = 0.126 Msun ; sec. stan. GJ 1061 (see below) Mass(M5.5V) = 0.124 Msun ; Mann18 calib. for M_Ks=8.78 Mass(M5.5V) = 0.1225 Msun ; Kervella16 BL Ceti (GJ 65A) Mass(M5.5V) = 0.1221 Msun ; sec. stan. GJ 551 = Proxima Centauri (Kervella17) Mass(M5.5V) = 0.120 Msun ; sec. stan. GJ 551 = Proxima Centauri (Ribas17) Mass(M5.5V) = 0.116 Msun ; Benedict16 calibration for M_Ks=8.98 Mass(M5.5V) = 0.114 Msun ; sec. stan. GJ 1002 (see below) Mass(M5.5V) = 0.112 Msun ; Delfosse00 calibration for M_Ks=8.98 => adopt Mass(M5.5V) = 0.124 Msun [last updated 8/2/2018] # Primary Standards GJ 1245AC = G 208-44 = LHS 3494 = NLTT 48414 M5+V: Boeshaar76 *M5.5V: Boeshaar85,Keenan85(M5.5Ve),Keenan88,Keenan89,Gliese91,Kirkpatrick91(pri),Kirkpatrick94(M5.5V comp.),Hawley97,Henry02(M5.5VJ),Geballe02,Reid04,Kirkpatrick(GrayCorbally09) M5.9: Mann15 M6V: Rodono80,McCarthy88 Unfortunately a tight binary, but probably the strongest pedigree as a M5.5V standard, and used over and over again going back to Boeshaar and Keenan, and continued by Kirkpatrick, Henry, Hawley, Reid, etc. Hawley97 says AC is a 0.1" binary with delta Vmag=2.5. Reid04 calls C a M7.0V. Notes on the G 208-44/5 binary and confusing nomenclature: Worley96 shows its a 7.8-11.0" binary, PA ~ 93-98 (epoch 1966-1978). G208-045 =GJ 1245B =LHS 3495(fainter, higher RA, same Dec; Giclas, Luyten). G208-044A =GJ 1245A =LHS 3494(brighter, Keenan89 says M5.5Ve). G208-044B =GJ 1245C. It appears that G208-044AB = GJ 1245AC. V=13.410(Mermilliod91;G208-44), B-V=1.900(Mermilliod91;G208-44), J=7.791+-0.023(2MASS), H=7.194+-0.016(2MASS), Ks=6.854+-0.016(2MASS). V-Ks = 6.556. Teffs: 2695K(Jenkins09), 2859+-60K(Mann15), 2890+-19K(Rojas-Ayala12), 2965+-115K(Newton14), 4064K(Wright11) => = 2890K. Plx = 212.0+-4.3 mas (Gliese91), 220.2+-1.5 mas (Harrington93; Dupuy12)*, 224.6+-5.4mas(Newton14). Mv=15.12. [M/H]=-0.09+-0.12(Rojas-Ayala12), [Fe/H]=-0.14+-0.17(Rojas-Ayala12). R=0.1430+-0.0069 Rsun(Mann15), M=0.103+-0.010 Msun(Mann15), [Fe/H]=-0.05+-0.08(Mann15). fbol=0.19860+-0.00320 (10pW/m2)(Mann15). # Secondary Standards GJ 1002 = LHS 2 = G 158-27 = NLTT 248 M5-M5.5: Boeshaar76(stan) *M5.5V: Bessell91,Henry94,Kirkpatrick94,Hawley97,Henry02(stan) plx = 213.0+-3.6mas(vanAltena95), 207.42+-1.23mas(Weinberger16). V=13.759+-0.034(Mermilliod91), B-V=1.978+-0.015(Mermilliod91), U-B=1.752+-0.128(Mermilliod91), J=8.323+-0.019(2MASS), H=7.792+-0.034(2MASS), Ks=7.439+-0.021(2MASS). V-Ks=6.32 (Merilliod91,2MASS). Teffs: 2750+-70K(Casagrande08), 3100K(Rajpurohit18), 3182K(Terrien15#1), 3292K(Terrien15#2) => = 3140 K. [Fe/H]=-0.19(Neves13). Mv = 15.34+-0.04. Using Mann18 calibration, and adopting [Fe/H]=-0.19+-0.1, 2MASS Ks and Weinberger16, assuming no reddening, I estimate mass Msun = 0.1142+-0.0046 Msun (4.0% unc.). GJ 1061 = LHS 1565 = LFT 295 = LTT 1702 = LP 995-46 = L 372-58 M5V: Bidelman85(M5),Dieterich12 *M5.5V: Henry97,Hawley97,Henry02(stan) M6V: Zakhozhaj79,Kirkpatrick12(Henry06) Henry97 reports: M5.5V with V=13.03 at d=3.7 pc, 20th closest star at the time. plx=268.66+-0.59(Weinberger16). V=13.030(Mermilliod91), V=13.09(Henry06), R=11.45(Henry06), I=9.46(Henry06), B-V=1.900(Mermilliod91), U-B=1.52(Mermilliod91), J=7.523+-0.020, H=7.015+-0.044(2MASS), Ks=6.610+-0.021(2MASS). V-Ks=6.48(Henry06,2MASS), V-Ks=6.426(Astudillo-Defru17). Mv=15.18+-0.01. Teffs: 2999+-41K(Gaidos14) => Teff = 2999K. R=0.19Rsun(Gaidos14), M = 0.14Msun(Gaidos14), M = 0.12Msun(Astudillo-Defru17). [Fe/H]=-0.08(Neves13). Using Mann18 calibration, adopting [Fe/H] = -0.08+-0.1, zero extinction, Weinberger16 parallax, I estimate mass Msun = 0.126+-0.005 Msun. GJ 551 = Proxima Centauri = LHS 49 M5V: Lurie14 *M5.5V: Boeshaar76(M5.5e),Bessell91,Henry97,Hawley97,Henry02(stan),Kirkpatrick(unpub.,DwarfArchive) M6Ve: Torres06 M7: Gaidos14 The famous Proxima Centauri - the closest star, the nearest brightest M5.5V star, one of the best studied M dwarfs in the sky, and known to be single. Buscombe95 mentions it as M5.3Ve, but doesn't cite the primary source. Segransan03 VLTI study reports: M = 0.123+-0.006 Msun, R = 0.145+-0.011 Rsun, Teff=3042+-117 K, logg=5.20+-0.23 dex. From Mann18 calibration, adopting [Fe/H]=0.22+-0.01 for alf Cen A, I estimate mass = 0.1201+-0.0049 Msun (4.1% error). Teffs: 2425K(Leger15,clearly erroneous) 2727+-12K(Pecaut13), 2883+-60K(Gaidos14), 2900K(Pavlenko17), 2900K(Rajpurohit13), 2920K(Morales08), 2979K(Wright11), 2980+-80K(Ribas17), 3042+-117K(Segranson03), 3054+-79K(Boyajian13) => = 2920K. J=5.357+-0.023(2MASS), H=4.835+-0.057(2MASS), Ks=4.384+-0.033(2MASS, grade 'E'; but seems consistent with other K values, see Ribas17 Table 4). Ribas17 gives through review of UBVRI photometry. B-V=1.886+-0.019(Mermilliod91), B-V=1.86(Bessell83), U-B=1.485+-0.055(Mermilliod91), V=11.111+-0.022(Mermilliod91), V=11.09(Bessell83), V-R=1.649(Bessell83), R-I=2.024(Bessell83), V-I=3.673(Bessell83), V-J=5.754+-0.032. V-Ks = 6.727+-0.040 (note that this is indeed roughly halfway between M5V median [5.942] and M6V median [7.300], and is roughly what one would predict for a typical star based on the V-J color -- the predicted V-K color would be 6.68.). plx = 771.64+-2.60(vanLeeuwen07), plx = 769.91+-0.54mas(Benedict99), Mv = 15.543+-0.022(V=11.111,plx=769.91), mbol = 7.331+-0.017 (see SED fit below), Mbol = 11.763+-0.017, logL = -2.809+-0.007. Best fit synthetic model using VOSA to published optical/near-IR photometry: BT-Settl 2900K logg=6 [M/H]=-0.5, alpha=0.2, chi^2=1.985e2: Fbol = 2.984e-8 4.675e-10 erg/s/cm^2: mbol = 7.33078 +- 0.017012 mag BCv = mbol - V = (7.331 +- 0.017) - (11.111+-0.022) = -3.780 +- 0.028 BCj = mbol - J = (7.331 +- 0.017) - (5.357+-0.023) = +1.974 +- 0.029. Ribas17 reports fbol = (2.86+-0.14)e-8 erg/s/cm2, which on IAU2015 system is mbol = 7.361+-0.053 mag. Hence the Ribas17 fbol is consistent with BCv = 7.361 - 11.111 = -3.75, BC_Ks = 7.361 - 4.384 = 2.977. # Tertiary Standard GJ 1286 = LHS 546 = G 157-77 M5V: Walker83,Gliese91,vanAltena95,Rojas-Ayala12(K-band) *M5.5V: Henry94,Hawley97,Henry02 V=14.69(Rajpurohit13), V=14.700(Mermilliod91), V=14.73(Hosey15), R=13.10(Hosey15), I=11.10(Hosey15), B=V=1.95(Mermilliod91), B-V=1.96(Gliese91), R=I=2.06(Delfosse98), J=9.148+-0.021(2MASS), H=8.505+-0.033(2MASS), Ks=8.183+-0.020(2MASS). V-Ks=6.517(Mermilliod91,2MASS). Teffs: 2800K(Rajpurohit13), 2936K(Stelzer13), 3000K(Rajpurohit18), 3012+-45K(Rojas-Ayala12), 3211K(Terrien15#1), 3290K(Terrien15#2)=> ~ 3006K. [Fe/H]=-0.04+-0.17(Rojas-Ayala12), [M/H]=-0.02+-0.12(Rojas-Ayala12). plx=138.30+-3.50(vanAltena95), 138.6+-3.6mas(Gliese91). Mv = 15.40. [Fe/H]=+0.2(Rajpurohit18). GJ 905 = LHS 549 = G 190-42 = G 171-10 = HH And = Ross 248 = NLTT 57692 M4.5: Bidelman85 M5V: Adams35(M5),Boeshaar76(stan;M5e),Hawley97 M5.2: Mann15 *M5.5V: Joy74(M5.5Ve),Kirkpatrick94,Henry94,Henry02(stan),Kirkpatrick12(Henry94) M6: Gaidos14 Not in WDS. V=12.294+-0.008(Mermilliod91), B-V=1.915+-0.005(Mermilliod91), U-B=1.480(Mermilliod91), J=6.884+-0.026(2M), H=6.247+-0.027(2M), Ks=5.929+-0.020(2M), V-Ks=6.365(Mermilliod91,2MASS). plx = 316.0+-1.1mas(vanAltena95). Teffs: 2764K(Jenkins09), 2799K(Ivanov04), 2930+-60K(Mann15#1), 3005+-62K(Gaidos14), 3013K(Stelzer13), 3043+-25K(Mann15#2), 3058+-65K(RojasAyala12), 3100K(Rajpurohit18), 3110K(Lepine13), 3222K(Terrien15#1), 3280K(Terrien15#2) => = 3043K. [Fe/H]=0.23+-0.08(Mann15), [Fe/H]=+0.5(Rajpurohit18). plx = 316.2+-1.4mas(Harrington93), 316.7+-0.7mas(Gatewood08). Mv = 14.80+-0.01. GJ 473AB = Wolf 424 = LHS 333 = LFT 923 = FL Vir = Ci 20 716 = G 12-43 = G 60-14 M5V: Hawley97(for A) *M5.5V: Boeshaar76,Henry92,Henry94(M5.5VJ),Kirkpatrick94(M5.5V comp),Boeshaar94(dM5.5),Henry02(M5.5VJ) Hawley97 says its a 0.8" binary with delta Vmag = 0.3. It is not obvious to me that a known barely-resolved binary should be a strong spectral standard star. Henry, Johnson, McCarthy, & Kirkpatrick (1992) studied the Wolf 424 system in detail: spectrum very similar to Gl 65A (M5.5V), and masses of 0.12-0.15 Msun for A, and 0.11-0.12 Msun for B, and M_K(A) = 8.46+-0.10, M_K(B) = 8.91+-0.15. delta(mags): delta(J) = 0.13+-0.04, delta(H) = 0.20+-0.12 (Henry92), delta(K) = 0.45+-0.24 (Henry92). V=12.455+-0.025(Mermilliod91), B-V=1.843+-0.016(Mermilliod91), U-B=1.270+-0.045(Mermilliod91), J=6.995+-0.024(2M), H=6.397+-0.034(2M), Ks=6.042+-0.020(2M). V-Ks=12.455-6.042=6.413. Teffs: 2850K(Lepine13), 2959+-100K(Newton15), 2979+-32K(Rojas-Ayala12), 3000+-64K(Gaidos14), 3013K(Stelzer13), 3234K(Terrien15#1), 3287K(Terrien15#2) => median Teff=3000K. [M/H]=0.05+-0.12(Rojas-Ayala12). # Deprecated Standards GJ 412B = LHS 39 = WX UMa = G 176-12 = LFT 758 = LTT 12977 = 2MASS J11053133+4331170 M5Ve: Bessell91 *M5.5V: Joy74,Henry94,Henry02(stan) M6V: Hawley97,Newton14(near-IR) M6.6: Mann15 M7: Gaidos14 I've deprecated this as a standard since 3 major recent surveys all systematically classified the star cooler, ranging from M6 to M7 (Newton14,Gaidos14,Mann15) systematically classify it at a cooler type. AB separation = 31.6" (WDS). AC separation 7.3" (not clear if C physical?). GCVS lists variability of 14.2 to 16.53 mag for WX UMa! V=14.40(Mermilliod91), B-V=1.99(Mermilliod91), U-B=1.18(Mermilliod91), J=8.742+-0.026(2M), H=8.177+-0.024(2M), Ks=7.839+-0.026(2M), V-Ks=14.40-7.839=6.561(Mermilliod91,2MASS). Teffs: 2700K(Casagrande08), 2800K(Leggett00), 2831+-60K(Gaidos14), 2863+-60K(Mann15), 2915+-18K(RojasAyala12) => = 2815K. Only made tertiary rather than secondary standard as it does not appear in the Kirkpatrick or Boeshaar papers as a standard, so it has limited pedigree. plx(GJ412A,primary)=206.27+-1.00mas(vanLeeuwen07). [Fe/H] = -0.03+-0.12(Newton14),-0.32+-0.08(Mann15). GJ 65A = G 768-26A = StKM 2-145 = BL Cet = LHS 9 *M5.5V: Joy74, Bessell91, Kirkpatrick91(pri),Kirkpatrick94,Hawley97,Henry02(stan) M6-V: Boeshaar76(combined A&B according to Kirkpatrick91),Boeshaar94(both AB). Washington Double Star catalog lists GJ 65 (WDS 01388-1758 = LDS 838) as a 2.1" binary as of epoch 2010, with V mags of 12.7(A) and 13.2(B). The companion (GJ 65B, LHS 10) is the infamous star "UV Ceti". Kervella16 has conducted comprehensive and interferometric and dynamical study of this system. Joy74, Kirkpatrick91, and Henry02 call consider the pair of stars A & B to be M5.5V and M6.0V, respectively. Reid04 lists GJ 65AB as M5.5V, but lists B as a M5.5V also. So most experts consider A & B to be ~0.5 subtype different, and they are ~0.5 mag different in V magnitude. It's not obvious that such a system is optimal for use as a standard star(s), especially if one is not blessed with <1" seeing. Geyer88 estimates parallax = 375+-4 mas. The 2MASS JHK and Mermilliod91 UBV photometry for GJ 65AB is unresolved. 2MASS unresolved photometry: J = 6.283+-0.019, H=5.690+-0.029, Ks=5.343+-0.021. Leggett96 models both AB unresolved: fbol = 1.31e-11 W/m^2 => mbol = 8.209 (IAU2015 scale) => BC_Ks = 8.209 - 5.343 = 2.866 (IAU2015 scale). Leggett96 original: logL=-2.54, mbol=8.23, Mbol=11.09, BCv=-3.77, BC_K=2.90. Kervella16: mass 0.1225+-0.0043 Msun. Teffs: 2900K(Kervella16,evol.tracks), 3000K(Kervella16,assumed for limb darkening), 3000K(Kochukhov17), 3167+-12K(Koleva12) => 3000K. GJ 1245B = G 208-45 = LHS 3495 = NLTT 48415 *M6V: Rodono80,McCarthy88,Kirkpatrick91(pri),Kirkpatrick93,Kirkpatrick94,Geballe02,CNS4 M5.5V: Boeshaar85(dM5.5),Reid04 Best considered a secondary M6V standard. 7" away from G208-44 = GJ 1245AC, and *not* G 208-44, which is considered a M5.5V standard, even though Reid04 classify "C" as a M7V. V=13.990(Mermilliod91), V=14.01(CNS4,Henry04), B-V=1.980(Mermilliod91), B-V=1.97(CNS4), Rc=12.36(Henry04), R-I=2.07(Delfosse98,CNS4), V-Rc = 1.65(Henry04), Ic=10.27(Henry04), V-Ic=3.74(Reid04,Henry04), J=8.275+-0.026(2MASS), H=7.728+-0.031(2MASS), Ks=7.387+-0.018(2MASS), V-J=5.715(Mermilliod91 & 2MASS), (V-Ks)=6.603(Mermilliod91 & 2MASS). Plx = 220.2+-1.5mas(Harrington93). Mv = 15.70+-0.01 mag, M_Ks = 9.10 +- 0.02 mag. Mass: 0.108Msun(Jenkins09). Using Casagrande10 relations, I estimate mbol=10.085+-0.025 mag, hence for Harrington93 parallax => Mbol=11.80mag, logL=-2.82. Teffs: 2673K(Jenkins09), 2859K(Mann15#1), 2881K(RojasAyala12), 2919+-34K(Mann15#2), 2944+-60K(Gaidos14) => median Teff = 2881K. GJ 1116AB = LHS 2076/7 = G 9-38AB = LP 426-40 = EI Cnc (A) *M5.5V: Henry94(M5.5VJ),Henry02(M5.5VJ) M5.5V+M5.5V: Hawley97,Kirkpatrick12(Forveille99) M6.15+M6.71: Terrien15(near-IR) M7V+M7V: Newton14(near-IR). M7: West15 I'm concerned about the lack of agreement between the recent near-IR spectral types (~M6/M7) and the optical types (M5.5). Gliese91, Mermilliod91, Oppenheimer01 lists V(A)=14.06, V(B)=14.92, B-V(A)=1.84, B-V(B)=1.93. Combined Mermilliod91 magnitudes yield unresolved V(AB)=13.654. Lepine05 lists V(A)=13.93, V(B)=13.75. Unresolved in 2MASS: J=7.791+-0.023(2M), H=7.244+-0.026(2M), Ks=6.889+-0.023(2M). Unresolved V-Ks=13.654-6.889=6.765. Reid04 says that the unresolved binary GJ 1116B is a M5.5V. WDS lists identical magnitudes 13.37 each, with separations ranging from 4.5" in 1960 to 1.8" in 2012. Newton15 resolved: Teff(A)=2821+-101K(Newton15), Teff(B)=2663+-92K(Newton15). GJ 2005ABCD = LHS 1070 = LP 881-64 = LNTT 1292 *M5.5V: Henry94(M5.5VJ),Hawley97,Henry02(M5.5VJ),Reid04 Rajpurohit11 (http://adsabs.harvard.edu/abs/2011sf2a.conf..339R) reports this system as a (M5.5-M6)+(M8.5)+(M9.5-M9), with Teffs of 2900, 2500, 2400 K using BT-Settl models, respectively, and Teff = 2900, 2600, 2500 K using MARCS models. GJ 4037 = LHS 3339 = LP 102-320 = NLTT 45700 M5V: Reid04 *M5.5V: Kirkpatrick91(sec) M6V: Boeshaar85(stan),Hawley97,Geballe02,Basri06 Depricated as a standard as it appears to have been little used since Kirkpatrick91. plx=61.10+-3.90mas(Dittman14), but see Dahn02. Not in Washington Double Star Catalog. Dahn02 derives: plx=46.4+-1.1 mas ((m-M)=1.67+-0.05), V=17.98+-0.02, R=16.20+-0.020, I=14.03+-0.01, K=10.78+-0.03, M_J = 10.05, BC_J = 2.02, Mbol = 12.07, R = 0.1308 Rsun, Teff = 2957+-70K. Hence, mbol = 13.74, and BCv = 13.74 - 17.98 = -4.24, BC_K = 13.74 - 10.875 = 2.87. V=17.90(Lepine05), V=17.98(Gliese91, vanAltena95), V=17.43(Salim03), J=11.819+-0.023(2MASS), H = 11.227+-0.023(2MASS), Ks=10.875+-0.016(2MASS). V-Ks=17.98-10.875=7.105. Teffs: 4100K(Morales08). # Other Stars LHS 3406 = GJ 4073 = 2MASS J18432213+4040209 = V492 Lyr = LP 229-30 M5.5V: Leggett01, Geballe02 M7.5Ve: Reid03 M8: Cruz03,Cruz07,Schmidt07,Faherty09,Reiners09,Deshpande12(M8V),Newton14(near-IR,M8V) Appear to be big offset between optical vs. near-IR type.