M0V Kirkpatrick (in GrayCorbally09) calls Gl 270 the primary M0V standard. Gl 270 has a legacy as a strong M0V standard going back to Kirkpatrick91 and Boeshaar76. JM53 standard: HD 147379 - M0V Houk75 standard: GJ 338AB (=HD 79210/1) - M0V+M0V (secondary standard) Boeshaar76 standard: GJ 270 - M0V [according to Kirkpatrick91] KeenanMcNeil76 stan.: GJ 172 - M0V Keenan80 standard: GJ 172 (=HD 232979) - M0V Keenan83 standard: GJ 172 (=HD 232979) - M0V Turnshek85 standard: GJ 172 (=HD 232979) - dM0 Keenan85 standards: GJ 172 (=HD 232979) - M0V GJ 123 (=HD 19305) - M0V Corbally86 standard: GJ 172 - M0V [from Keenan80] Kirkpatrick91 standard: GJ 270 - M0V [primary standard] GJ 328 - M0V [primary standard] GJ 734A (= HD 230017) - M0V [sec. standard] GJ 763 (=HD 184489) - M0V [sec. standard] GJ 338A (=HD 79211) - M0V [sec. standard] GJ 748.2B (=G 22-21B) - M0V [sec. standard] Hawley02 standard: GJ 270 - M0V Henry02 standards: GJ 338A - M0V [from Kirkpatrick91] GJ 686 - M0V [from Henry94] GJ 701 - M0V [from Henry94] GJ 809 - M0V [from Henry94] Kirkpatrick09 standard: GJ 270 - M0V (primary standard) Kirkpatrick10 standard: GJ 270 - M0V (primary standard, optical & near-IR) Pecaut13 standard: GJ 701 - M0V [from Henry02] Kirkpatrick16 standard: GJ 270 (=BD+33_1505) - M0V Newton14 standard: GJ 123 - M0V Kirkpatrick12 lists 5 M0V stars within 8 pc: GJ 338A (B-V=1.410), GJ 784 (B-V=1.431), GJ 809A (B-V=1.483), GJ 701 (B-V=1.510). RECONS shows GJ 825 (J2117-3852) as the nearest M0.0V star, and only shows 2 M0.0V stars among the nearest 100: GJ 338 A (B-V=1.41) and GJ 784 (B-V=1.431) Note that Garrison94 (or Table A.1 in GrayCorbally09) does not list any M-type dwarfs as "anchors" (indeed he lists no dwarf anchors later than K5V; 61 Cyg A). For the best standards for the M-type dwarfs, we rely on the "primary standards" as given by Davy Kirkpatrick in Chapter 9 of Gray & Corbally (2009; "Stellar Spectral Classification", Princeton Series in Astrophysics, Princeton Univ. Press, Princeton). Henry et al. (2002; Table 2) provides an excellent modern compilation of K5-M9 dwarf standards. Henry's compendium contains K5, K7, M0-M9, and one ">M9.0V" (LP944-20). Wing & Yorka (1979) compares M-types published by Beoshaar (1976), Joy & Abt, Kuiper, and Vyssotsky (various publications). They provide a table (II) for converting Joy & Abt's types and Kuiper's types to the MK system for M dwarfs defined by Boeshaar. Note that Wing & Yorka put K5 and M0 one subtype apart. Joy74's M0V appears to correspond to ~K7V (e.g. HD 201092, HD 88230, BD+57 150B). KeenanMcNeil76 provide many M dwarf standards from M0V to M5.5V, however roughly half of these appear to have been subsequently ignored (i.e. haven't been adopted in the literature), and I list them as "deprecated" standards in my notes. Their Plate #8 shows "Image-tube spectra of M-dwarfs", which shows "spectrograms furnished by P. Boeshaar" and "For the M-type stars of the main sequence we adopt the scale of types of Boeshaar (1976).", however the Boeshaar 1976 reference is to the PhD thesis ("To be published"). However there appears to be some disagreement on the use of standards between the final published Boeshaar76 (much of which was adopted by Kirkpatrick91 and subsequent publications), e.g. KeenanMcNeil76 adopt Gl 172 as the M0V standard, but Boeshaar76 adopts GJ 270 (according to Kirkpatrick91, I have not yet seen the Boeshaar76 thesis). Torres10 (AJ, 140, 1158) notes that Flower96's bolometric corrections "break down completely for M dwarfs", so we presume that they are not useful (except only as a historical comparison for Teff ~< 3810K). Morgan38 used the three bright giants del Oph, gam Eri, and alf Cet "defined as M0 at Mt Wilson, were considered to be standard of that type for the dwarfs" - using the red TiO band. Morgan53 listed types K5, K6, M0 - without intermediate types, listing 61 Cyg B as K6 (along with Cin 2238, Cin 2322, Gmb 1618, and Castor C). He classified Lalande 18115 A and B as M0. Median metallicity of field M dwarfs: Newton14 estimates metallicities for 447 nearby M dwarfs in the MEarth survey. Their 2014 calibration metallicities have the following distribution: <[Fe/H]> = +0.04 dex (+-0.26, 68%CL; +0.43,-0.60 95.5%CL). Mann15 estimates metallicities for 183 nearby M dwarfs. Their values are consistent with <[Fe/H]> = -0.03 dex (+-0.21, 68%CL; +-0.43, 95.5%CL). Hence, color-absolute magnitude sequences through the locus of points for nearby field M dwarfs should correspond approximately to solar composition (within ~0.04 dex). Silverstein19 divides M dwarfs and subdwarfs with a "Main Sequence-Subdwarf Boundary" (Eqn. 5.1) as the line between 4000K/0.485Rsun and 3100K/0.085Rsun: R/Rsun = 4.444e-4*Teff - 1.293. (M0V) = 1.347 ; Crawford76 (M0V) = 1.35 ; Leggett92 "young disk" (M0V) = 1.35 ; Leggett92 "old disk" (B-V)(M0V) = 1.366 ; exemplar GJ 839 (M0V) = 1.37 ; Fitzgerald70 (B-V)(M0V) = 1.385 ; deprecated standard GJ 123 (B-V)(M0V) = 1.388 (+-0.017 sem, +-0.082 stdev); med. for 25 ARICNS M0V stars (B-V)(M0V) = 1.40 ; SchmidtKaler82 (B-V)(M0V) = 1.41 ; Johnson66, KenyonHartmann95 (B-V)(M0V) = 1.41 ; Bessell91 "old disk" (B-V)(M0V) = 1.410 ; sec. stan. GJ 338A (B-V)(M0V) = 1.412(+-0.013 sem, +-0.057 stdev); 12 Kirkpatrick(DwarfArchive) M0V stars (B-V)(M0V) = 1.414 ; sec. stan. GJ 328 (B-V)(M0V) = 1.419 ; exemplar GJ 338B (B-V)(M0V) = 1.420 ; prim. stan. GJ 270 (M0V) = 1.421 ; 27 Gray01/03/06 M0V (+-0.011 sem, +-0.065 stdev) (B-V)(M0V) = 1.431 ; exemplar GJ 784 (B-V)(M0V) = 1.433 ; median Koen10 d<25pc M0V (B-V)(M0V) = 1.434 ; median SIMBAD M0V d<25pc (N=97) (B-V)(M0V) = 1.458 ; mean of 4 M0V stars within 8 pc (Kirkpatrick12 list) (B-V)(M0V) = 1.483 ; deprecated stan. GJ 809 (B-V)(M0V) = 1.508 ; deprecated stan. GJ 701 (B-V)(M0V) = 1.530 ; deprecated stan. GJ 686 => adopt (B-V)(M0V) = 1.42 [updated 8/13/2020] (U-B)(M0V) = 1.197 ; HIP d<75pc S/N>8 M0V N=42 (M0V) = 1.25 ; Young Disk ; Leggett92 (M0V) = 1.25 ; Old Disk ; Leggett92 (U-B)(M0V) = 1.26 ; Johnson66 (V-Ic)(M0V) = 1.692 ; from V-Ks=3.65 (V-Ic)(M0V) = 1.735 (+-0.029 sem, +-0.158 stdev; N=27; Gray01/03/06) (V-Ic)(M0V) = 1.80 ; Bessell91 "old disk" (V-Ic)(M0V) = 1.836 (+-0.019 sem, +-0.145 stdev; N=49; Koen10) (V-Ic)(M0V) = 1.9 ; Hawley96 (V-Ic)(M0V) = 2.013 (+-0.120 sem, +-0.240 stdev; N=4 standards => adopt (V-Ic)(M0V) = 1.692 [updated 8/13/2020] (V-R)(M0V) = 0.89 ; Bessell91 "old disk" (R-I)(M0V) = 0.91 ; Bessell91 "old disk" (M0V) = 3.114 (+-0.088 sem, +-0.175 stdev; N=4) (M0V) = 2.94 (+-0.21 stdev) ; Lepine12 (V-Ks)(M0V) = 3.409 ; deprecated standard GJ 123 (V-K_CIT)(M0V) = 3.43 ; Leggett92 "old disk" (M0V) = 3.47 ; Beuermann06 (V-K_CIT)(M0V) = 3.47 ; Leggett92 "young disk" (V-Ks)(M0V) ~ 3.55 ; sec. stan. GJ 338A (based on Johnson V-K) (V-Ks)(M0V) = 3.561 ; exemplar GJ 338B (V-Ks)(M0V) = 3.570 ; exemplar GJ 839 (V-Ks)(M0V) = 3.603 ; sec. stan. GJ 328 (V-K)(M0V) = 3.642 (+-0.058 sem, +-0.284 stdev; N=12 Kirkpatrick(DwarfArchive) M0Vs) (V-Ks)(M0V) = 3.65 (+-0.02) ; Fouque17 (mean for N=50) (V-K)(M0V) = 3.65 ; Bessell91 "old disk" (V-Ks)(M0V) = 3.655 ; trend K/M standards & exemplars (V-Ks)(M0V) = 3.684 ; pri. stan. GJ 270 (V-Ks)(M0V) = 3.686 ; exemplar GJ 784 (V-K)(M0V) = 3.8 ; Hawley96 (V-Ks)(M0V) = 3.932 ; deprecated stan. GJ 809 (V-Ks)(M0V) = 4.048 ; deprecated stan. GJ 686 (V-Ks)(M0V) = 4.064 ; deprecated stan. GJ 701 => adopt (V-Ks)(M0V) = 3.65 [last updated 8/13/2020] => adopt (G-Ks)(M0V) = 2.95 = (V-Ks)+(G-V) = 3.65+(-0.70) => adopt (U-B)(M0V) = 1.206 => adopt (V-R)(M0V) = 0.866 => adopt (R-I)(M0V) = 0.826 => adopt (V-J)(M0V) = 2.833 => adopt (V-H)(M0V) = 3.460 => adopt (H-Ks)(M0V) = 0.190 => adopt (J-H)(M0V) = 0.627 => adopt (V-Hp)(M0V) = -0.085 (M0V) = 0.17 ; Beuermann06 (M0V) = 0.85 ; Beuermann06 (G-J)(M0V) = 2.058 ; Bentley18 (G-Ks)(M0V) = 2.907 ; Bentley18 (Ks-W2)(M0V) = 0.126 ; Bentley18 (W1-W2)(M0V) = 0.013 ; Bentley18 (Ks-W1)(M0V) = 0.120 ; fit to Winters15 data for V-Ks=3.65 (Ks-W1)(M0V) = 0.120 ; EEM trend for d<30pc for V-Ks=3.65 (Ks-W1)(M0V) = 0.113 ; Bentley18 (Ks-W1)(M0V) = 0.064 ; Avenhaus12 for V-Ks=3.65 => adopt (Ks-W1)(M0V) = 0.12 [updated 12/29/2019] (Bp-Rp)(M0V) = 1.7365 ; GJ_123 deprecated standard (GaiaDR2) (Bp-Rp)(M0V) = 1.79 ; Kiman19 (GaiaDR2) (Bp-Rp)(M0V) = 1.79598 ; GJ_839 exemplar (GaiaEDR3) (Bp-Rp)(M0V) = 1.8050 ; HD_232979 (GaiaDR2) (Bp-Rp)(M0V) = 1.8059 ; GJ_839 exemplar (GaiaDR2) (Bp-Rp)(M0V) = 1.81730 ; GJ_338A sec. stan. (GaiaEDR3) (Bp-Rp)(M0V) = 1.8235 ; GJ_338A sec. stan. (GaiaDR2) (Bp-Rp)(M0V) = 1.8324 ; GJ_328 sec. stan. (GaiaEDR3) (Bp-Rp)(M0V) = 1.8409 ; GJ_328 sec. stan. (GaiaDR2) (Bp-Rp)(M0V) = 1.84645 ; GJ_338B = HD_79211 exemplar (GaiaEDR3) (Bp-Rp)(M0V) = 1.8529 ; GJ_338B = HD_79211 exemplar (GaiaDR2) (Bp-Rp)(M0V) = 1.8814 ; GJ_270 pri. stan. (GaiaEDR3) (Bp-Rp)(M0V) = 1.8893 ; GJ_270 pri. stan. (GaiaDR2) (Bp-Rp)(M0V) = 1.91171 ; GJ_784 = HD_191849 exemplar (GaiaEDR3) (Bp-Rp)(M0V) = 1.9159 ; GJ_784 = HD_191849 exemplar (GaiaDR2) (Bp-Rp)(M0V) = 2.0323 ; *_41_Ara_B M0Vp_Ca-3_Cr-1 (GaiaDR2) => adopt (Bp-Rp)(M0V) = 1.84 [GaiaDR2; updated 7/10/2020] => adopt (Bp-Rp)(M0V) = 1.85 [GaiaEDR3; updated 12/7/2021] (G-Rp)(M0V) = 0.8733 ; GJ_123 deprecated stan. (G-Rp)(M0V) = 0.9004 ; GJ_839 exemplar (G-Rp)(M0V) = 0.9095 ; GJ_338A sec. stan. (G-Rp)(M0V) = 0.9194 ; GJ_328 sec. stan. (G-Rp)(M0V) = 0.9228 ; GJ_338B = HD_79211 exemplar (G-Rp)(M0V) = 0.927 ; color trend M0V-M9V (G-Rp)(M0V) = 0.93 ; Kiman19 (G-Rp)(M0V) = 0.9356 ; GJ_328 sec. stan. (Gaia EDR3) (G-Rp)(M0V) = 0.9313 ; GJ_270 pri. stan. (G-Rp)(M0V) = 0.9419 ; HD_191849 exemplar (G-Rp)(M0V) = 0.9583 ; GJ_270 pri. stan. (Gaia EDR3) (G-Rp)(M0V) = 0.9983 ; *_41_Ara_B M0Vp_Ca-3_Cr-1 => adopt (G-Rp)(M0V) = 0.92 [updated 11/18/2020] => adopt (Bp-G)(M0V) = 0.92 [last updated 7/10/2020; Bp-Rp=1.84, G-Rp=0.92] (Bp-G)(M0V) = 0.87 ; Kiman19 (G-V)(M0V) = -0.741 ; SIMBAD d<20pc median for M0V (G-V)(M0V) = -0.731 ; GJ 784 = HD 191949 exemplar (G-V)(M0V) = -0.729 ; polynomial fit to SIMBAD d<25pc M dwarfs by type (G-V)(M0V) = -0.706 ; GJ 328 = HIP 43790 sec. stan. (Gaia EDR3) (G-V)(M0V) = -0.702 ; median N=271 M0V d<60pc (G-V)(M0V) = -0.700 ; GJ 270 pri. stan. (Gaia EDR3) (G-V)(M0V) = -0.693 ; trend for SIMBAD d<20pc for V-Ks=3.65 (G-V)(M0V) = -0.686 ; trend for Kervella19 d<25pc for V-Ks=3.65 (G-V)(M0V) = -0.6751 ; GJ 338A = HD 79210 sec. stan. (G-V)(M0V) = -0.668 ; GJ 839 = LHS 3727 exemplar (G-V)(M0V) = -0.649 ; GJ 338B = HD 79211 exemplar (G-V)(M0V) = -0.6207 ; GJ_123 deprecated stan. => adopt (G-V)(M0V) = -0.70 [updated 12/23/2020] => adopt (G-Ks)(M0V) = 3.65 + -0.70 = 2.95 [updated 12/23/2020] (g-r)(M0V) = 1.31 ; Covey07 (r-i)(M0V) = 0.66 +- 0.12 (rms) ; West08 (i-z)(M0V) = 0.38 +- 0.07 (rms) ; West08 (z-J)(M0V) = 1.23 +- 0.19 (rms) ; West08 Teff(M0V) = 3655 K ; deprecated stan. GJ 701 Teff(M0V) = 3657 K ; deprecated stan. GJ 686 (median Teff) Teff(M0V) = 3762 +- 71K ; Lepine12 Teff(M0V) = 3763 K ; pri. stan. GJ 270 (median Teff) Teff(M0V) = 3764 K ; Morrell19 Teff for stars w/i +-0.1 mag of M_Ks=5.23 Teff(M0V) = 3779 K ; depreciated stan. GJ 809 Teff(M0V) = 3800 K ; Bessell91 "old disk" Teff(M0V) = 3805 K ; smooth Teff(SpT) trend Teff(M0V) = 3807 K ; EEM median of 24 Teffs Teff(M0V) = 3835 K ; candidate standard GJ 839 median Teff Teff(M0V) = 3850 K ; Schmidt-Kaler82 Teff(M0V) = 3855 K ; Rad=0.5735Rsun for Mann15 calib for M_K=5.20, [Fe/H]=0.0 Teff(M0V) = 3870 K ; sec. stan. GJ 328 Teff(M0V) = 3880 K ; empirical M-R relation ** Teff(M0V) = 3888 K ; mean photometric Teff Teff(M0V) = 3900 K ; Rajpurohit13 (N=1, LHS 141) Teff(M0V) = 3907 +- 35 K ; Boyajian12b (N=1) Teff(M0V) = 3928 K ; deprecated stan. GJ 172 Teff(M0V) = 3930 K ; sec. stan. GJ 338A Teff(M0V) = 3951 K ; RojasAyala12(mean N=6 M0V stars) Teff(M0V) = 3990 K ; Bertone04[NextGen] Teff(M0V) = 4010 K ; Bertone04[ATLAS] Teff(M0V) = 4020 K ; ter. stan. GJ 123 Teff(M0V) = 4022 K ; Passegger18 median Teff for CARMENES M0.0Vs(N=20) => adopt Teff(M0V) = 3850 K (logT = 3.585) [updated 9/4/2020] Mv(M0V) = 7.8 mag ; Reid04 Mv(M0V) = 8.21 mag ; ter. stan. GJ 123 Mv(M0V) = 8.31 mag ; exemplar GJ 839 Mv(M0V) = 8.38 mag ; sec. stan. GJ 328 Mv(M0V) = 8.64 mag ; sec. stan. GJ 338A Mv(M0V) = 8.68 mag ; Kirkpatrick94 Mv(M0V) = 8.69 mag ; median Koen10 d<25pc M0V Mv(M0V) = 8.69 mag ; exemplar GJ 338B=HD 79211 Mv(M0V) = 8.76 mag ; pri. stan. GJ 270 Mv(M0V) = 8.8 mag ; Schmidt-Kaler82 Mv(M0V) = 8.80 mag ; V-Ks=3.65 => MS smooth trend K/M dwarfs Mv(M0V) = 8.82 mag ; V-Ks=3.65 => EEM fit to Jao16 data Mv(M0V) = 8.85 mag ; V-Ks=3.65 & M_Ks=5.20 (see below) Mv(M0V) = 8.91 mag ; V-Ks=3.68 => JohnsonApps09 Mv(M0V) = 8.96 mag ; Henry94 Mv(M0V) = 9.02 mag ; exemplar GJ 784 Mv(M0V) = 9.06 mag ; median SIMBAD M0V d<25pc (N=97) Mv(M0V) = 9.17 mag ; Wegner07 => adopt Mv(M0V) = 8.80 mag [updated 3/2/2021] (V-Ks=3.65, M_Ks=5.15) => adopt M_G(M0V) = 8.10 mag [updated 3/2/2021] (Mv=8.80, G-V=-0.70) => adopt M_Ks(M0V) = 5.15 mag [updated 3/2/2021] (Mv=8.80, V-Ks=3.65) M_G(M0V) = 7.68287 ; HD 111631 M0V M_G(M0V) = 7.729 ; sec. stan. GJ 328 M_G(M0V) = 7.96756 ; HD 11507 M0V M_G(M0V) = 8.03977 ; HD 79211 exemplar M_G(M0V) = 8.077 ; SIMBAD d<20pc trend for V-Ks=3.65 M_G(M0V) = 8.13 ; Kiman19 M_G(M0V) = 8.15 ; Mv=8.85, G-V=-0.70 M_G(M0V) = 8.28686 ; HD 191849 M_G(M0V) = 8.326 ; SIMBAD d<20pc median for M0V M_G(M0V) = 8.382 ; trend d<10pc SIMBAD M_G(M0V) = 8.38116 ; * 41 Ara B M_G(M0V) = 8.57797 ; HD 304636 M_G(M0V) = 8.87426 ; HD 260655 M_Ks(M0V) = 6.03 ; sec. stan. GJ 686 M_Ks(M0V) = 5.32 ; V-Ks=3.65 => Henry04 fit M_Ks(M0V) = 5.24 ; V-Ks=3.68 => EEM fit 4/2017 M_Ks(M0V) = 5.20 ; V-Ks=3.65 => JohnsonApps09 M_Ks(M0V) = 5.18 ; V-Ks=3.65 => EEM fit to Jao16 M_Ks(M0V) = 5.15 ; V-Ks=3.65 => smooth MS K/M dwarf trend M_Ks(M0V) = 5.10 ; V-Ks=3.65 => EEM fit to Reid CNS3 data M_Ks(M0V) = 5.07 ; pri. stan. GJ 270 M_Ks(M0V) = 4.81 ; ter. stan. GJ 123 M_Ks(M0V) = 4.79 ; sec. stan. GJ 328 BCv(M0V) = -1.558 mag ; deprecated stan. GJ 701 BCv(M0V) = -1.549 mag ; deprecated stan. GJ 686 BCv(M0V) = -1.400 mag ; Flower96(Teff=3840K) [unreliable for M *s, see Torres10] BCv(M0V) = -1.349 +- 0.038 ; sec. stan. GJ 809 (Pecaut13) BCv(M0V) = -1.253 mag ; Casagrande18(Teff=3840K,logg=4.5) BCv(M0V) = -1.25 mag ; Schmidt-Kaler82(BCv=-1.38 + 0.13 offset) BCv(M0V) = -1.21 mag ; Bessell91("old disk"; BCv = (V-I)-BC_I) BCv(M0V) = -1.184 mag ; Mann15(V-J=2.862) BCv(M0V) = -1.176 mag ; Bessell98(ATLAS9,logg=4.5,Teff=3840K) BCv(M0V) = -1.173 +- 0.037 ; deprecated standard GJ 338A (Pecaut13) BCv(M0V) = -1.15 mag ; BC_Ks = 2.50, V-Ks=3.65 BCv(M0V) = -1.149 mag ; Pecaut13(V-K=3.65, V-J=2.833) BCv(M0V) = -1.148 mag ; pri. stan. GJ 270 (see notes below) BCv(M0V) = -1.148 mag ; Morrel19 trend for G-Ks=2.96 => BC_Ks, assume V-Ks=3.65 BCv(M0V) = -1.079 mag ; EEM fit to Casagrande06/08/10 for Teff=3900K) BCv(M0V) = -1.05 mag ; Bertone04[NextGen] BCv(M0V) = -1.021 mag ; Bertone04[ATLAS,Teff=3900K] => adopt BCv(M0V) = -1.15 mag [updated 9/4/2020; V-Ks=3.65, BC_Ks=2.50] BC_K(M0V) = 2.613 ; Leggett01 calibration for J-K=0.825 BC_K(M0V) = 2.536 ; pri. stan. GJ 270 (see notes below) BC_K(M0V) = 2.53 ; smoothed trend K8V-L0V for M0V BC_K(M0V) = 2.513 ; deprecated stan. GJ 701 (see notes below) BC_Ks(M0V)= 2.512 ; Mann15(V-J=2.833) BC_Ks(M0V)= 2.498 ; Morrell19 trend for G-Ks=2.95 BC_K(M0V) = 2.491 ; deprecated stan. GJ 686 (see notes below) => adopt BC_K(M0V) = 2.50 mag [updated 9/4/2020; V-Ks=3.65, BCv=-1.15] logL(M0V) = -1.51 dex ; deprecated stan. GJ 686 logL(M0V) = -1.215 dex ; Morrell19 trend for LogL for M_Ks=5.23 logL(M0V) = -1.164 dex ; M_Ks=5.15, BC_Ks=2.50 => Mbol = 7.65 logL(M0V) = -1.09 dex ; pri. stan. GJ 270 => adopt logL(M0V) = -1.164 dex [updated 3/2/2021] => adopt Mbol(M0V) = 7.650 mag [updated 3/2/2021] Mass(M0V) = 0.50 Msun ; deprecated stan. GJ686 (Gaidos14)] Mass(M0V) = 0.512 Msun ; Mv=8.91 => Benefict16 calib Mass(M0V) = 0.568 Msun ; M_Ks=5.20 => Mann18 calib. Mass(M0V) = 0.571 Msun ; Eker15 calibration for logL=-1.204 Mass(M0V) = 0.580 Msun ; Eclipsing binary M0V NGTSJ0930-18A (Acton20) Mass(M0V) = 0.584 Msun ; Mv=8.91 => HenryMcCarthy93 calibration Mass(M0V) = 0.618 Msun ; M_Ks=5.20 => Benedict16 calibration Mass(M0V) = 0.615 Msun ; Delfosse00 calib. for M_Ks=5.2 Mass(M0V) = 0.616 +-0.006 Msun ; GU Boo A (Benedict16) Mass(M0V) = 0.62 Msun ; pri. stan. GJ270 (Gaidos14) Mass(M0V) = 0.665 Msun ; Mv=8.91 => Torres10 binary calibration => adopt Mass(M0V) = 0.57 Msun [updated 11/3/2019] Rad(M0V) = 0.47 Rsun ; ter. stan. GJ686 (Gaidos14) Rad(M0V) = 0.515 Rsun ; sec. stan. GJ809 (Mann14) Rad(M0V) = 0.54 Rsun ; sec. stan. GJ809 (Gaido14) Rad(M0V) = 0.57 Rsun ; pri. stan. GJ270 (Gaidos14) Rad(M0V) = 0.574 Rsun ; Rabus19 trend for Teff=3840K Rad(M0V) = 0.5773 +- 0.0131 Rsun ; Boyajian12b (N=1) Rad(M0V) = 0.5823 Rsun ; Mann15 trend M_Ks=5.15, [Fe/H]=0.0 Rad(M0V) = 0.584 Rsun ; Eclipsing binary NGTSJ0930-18 A (Acton20) Rad(M0V) = 0.5885 Rsun ; logL=-1.164, Teff=3850K Rad(M0V) = 0.5965 Rsun ; Morrell19 (Teff=3900K) => adopt Rad(M0V) = 0.588 Rsun [updated 3/2/2021] # No standard Boeshaar85 did not list a M0V standard. Keenan89 did not list a M0V standard, but did list non-standards GJ 123 (HD 19305) M0V and eta Cas B (HD 4614B) M0-V. # Primary Standard GJ 270 = BD+33_1505 = G 87-33 = LHS 1912 = HIP 35495 (J0719+3249) K7V: Stephenson86,Hawley97(K7) *M0V: Vyssotsky43,Boeshaar76,Bidelman85(M0),Kirkpatrick91(pri),Hawley02(stan),Kirkpatrick(GrayCorbally09)(pri),Lepine13,Alonso-Floriano15 M1V: Adams26,Gaidos14 M1.5V: Joy74 M2V: Adams35 K5: Lee47 Not mentioned in Henry02. Strange variation of Vmags in the literature ranging from V=8.92(Hawley97), V=9.16 (Mermilliod91) up to V=10.08(Weis93), V=10.06(HIP). The Hipparcos Hp magnitude is ~10.15 with scatter of 0.026 mag, and supporting V ~ 10.1. Endl06 reports "The M0 V star GJ 270 (= HIP 35495 = G 87-33 = BD +33 1505) also exhibits a linear RV acceleration. We fit a trend of +171.4+-2.2 m/s/yr with a chi^2_red of 1.42 (dof=26). The residual rms scatter of the RV measurements around this linear RV trend is 12.0 m/s. This trend is presumably caused by a previously unknown stellar companion in a long periodic orbit. The Hipparcos data for this star do not detect any astrometric perturbation, which also points toward a long period of the binary." However, Kervella19 shows that, in comparing Hipparcos to Gaia astrometry, there is a huge discrepency, translating to a tangential velocity anomaloy of about 298+-13 m/s. [seems to be some serious discrepencies in the Vmags]: V=9.16+-0.010(Mermilliod91), V=9.89(Brorfelde 1968-1984), V=10.03(CMC99), V=10.037+-0.073(Kharchenko07), V=10.050+-0.053 (Tycho-2=>Johnson), V=10.051(Rufener88), V=10.06(HIP,Salim03,Lepine05), V=10.07(Gliese91), V=10.08(Weis93), Hp=10.1473+-0.026(scatter; HIP), V=10.184+-0.060(Droege07), V=10.21+-0.05(GSC2.2), The HIP Vmag is essentially the median, so I adopt V=10.06 for calculating colors and abs mag. B-V=1.420+-0.010(HIP), B-V=1.44(Gliese91), B-V=1.45(Weis93), B-V=1.415+-0.015(Mermilliod91), B-V=1.408+-0.123(Tycho-2=>Johnson), B-V=1.40(vanAltena95), U-B=0.760+-0.040(Mermilliod91), J=7.184+-0.020(2MASS), H=6.541+-0.034(2MASS), Ks=6.376+-0.020(2MASS), K=6.39,6.37(Gezari99), V-I=1.72+-0.02(HIP), R-I=0.70(Gliese91), V-R=0.70(Weis93), UVW = +73.6,-37.6,+3.6(Bobylev06). V-J=2.876(HIP,2MASS), (V-Ks)=3.684(HIP,2MASS). Using Casagrande08 relations and 2MASS JHKs, mbol = 8.912+-0.024 => BCv = mbol - V = 8.912 - 10.06 = -1.148, BC_Ks = 8.912 - 6.376 = 2.536. Plx = 54.8734+-0.0422 mas(GaiaDR2) => Mv = 8.76, M_Ks = 5.073+-0.020, Mbol = 7.609+-0.024, logL = -1.148. Teffs: 3570+-144K(Alonso96), 3668+-54K(Ramirez05), 3700K(Lepine13), 3763K(V-K=>Casagrande08 calibration), 3833K(V-K=>vanBelle09 calibration), 3930K(Morales08), 3941K(Gaidos13) => median Teff = 3763K. Gaia EDR3: plx= 54.8692+-0.0302mas, G=9.360454 0.002794, E(BP/RP)=1.327, Bp-Rp=1.881377, Bp-G=0.923124, G-Rp=0.958253. G-V = 9.360454 - 10.06 = -0.700. # Secondary Standard GJ 338A = HD 79210 = LHS 260 = HIP 45343 K2: Cannon K7V: Wilson62,Bidelman85(K7),Hawley97(K7) K7.8: Mann15 K8: Luyten79 *M0V: Adams26,Morgan38,Roman55,Vyssotsky56(M0p),Worley70(M0),Houk75(stan,A+B),Stephenson86,Gliese91(M0Ve),Kirkpatrick91(sec.stan),Henry94,Henry02,Royas-Ayala12(M0;K-band),Gaidos14(M0),Newton14(near-IR),Alonso-Floriano15,Dieterich14(M0.0V) M0.5V: Joy74 Long history classified as M0V back to 1920s. Cannon HD listed the pair as both K2? Houk75 considered the pair GJ 338AB as M0V standard. Cowley67 mentions strong H and K emission for both A and B, but lists Roman55 type. Kirkpatrick91 considered it secondary standard. Vmag and B-V colors for pair are almost identical: V(A)=7.644+-0.033, V(B)=7.697+-0.030, B-V(A)=1.410+-0.017, B-V(B)=1.419+-0.018, (all Mermilliod91). V(A)=7.64(HIP). WDS reports Vmag = 7.79, 7.88. 2MASS photometry is poor, but K=4.09(Morel78), presumably on Johnson system. So V-K(Johnson) = 3.554. Boyajian12 reports Teff(A)=3907+-35K and Teff(B)=3867+-37K, so the types should be virtually identical. G = 6.9689+-0.0005 mag, Bp-Rp=1.8235, Bp-G=0.9140, G-Rp=0.905(GaiaDR2). Teffs: 3769K(Cennaro01), 3851K(Jenkins09), 3825K(Prugniel07), 3849+-27K(Prugniel11), 3868K(Prugniel07#2), 3896+-24K(Pecaut13), 3907+-35K(Boyajian12), 3920+-60K(Mann15), 3930+-52K(Mann15#2), 3953+-41K(Newton15), 3955+-106K(Newton15#2), 3973+-22K(Luck17), 3990+-88K(Gaidos14), 3991+-66K(Gaidos14#2), 3995K(GaiaDR2), 4012K(Katz11), 4031+-56K(Royas-Ayala12) => = 3930K. plx = 157.8796 0.0366 mas (GaiaDR2). Mv = 8.64 +- 0.03 (Mermilliod91,GaiaDR2). G-V = 6.9689 - 7.644 = GJ 328 = HIP 43790 = Ross 623 = BD+2_2098 = LHS 255 = G 46-9 = G 114-21 = LFT 616 = LTT 12331 K5V: Lee47(K5),Stephenson86 K7: Bidelman85,Hawley97 *M0V: Vyssotsky56,Kirkpatrick91(pri),Lepine13(M0.0),Gaidos14 M0.5V: Boeshaar76 M1V: Joy74 Primary M0V standard in Kirkpatrick91, but surprisingly little agreement before then. It does appear to have the colors nearest the middle of the distribution for M0V standards and exemplars. Lepine13 uses multiple spectral indices and lists M subtype as -0.07. Exoplanet host star (Robertson13: 2013ApJ...774..147R) to the "most massive, longest-period planet discovered around a low-mass dwarf" (2 Mjup, P=11yr). V=9.961+-0.029(Mermilliod91), V=9.955+-0.001(Koen10), V=9.99(HIP), B-V=1.372+-0.007(HIP), B-V=1.401+-0.021(Mermilliod91), B-V=1.414+-0.008(Koen10), U-B=1.246+-0.035(Mermilliod91), U-B=1.273+-0.012(Koen10), V-Rc=0.883+-0.003(Koen10), V-I=1.751+-0.004(Koen10), V-Ic=1.76+-0.02(HIP), J=7.191+-0.027(2MASS), H = 6.523+-0.018(2MASS), Ks = 6.352+-0.026(2MASS), V-Ks = 9.955 - 6.352 = 3.603. Using 2MASS photometry & Casagrande08 relations => mbol = 8.900+-0.023, Although Casagrande08 themselves list: mbol = 8.830. Teffs: 3828+-168K(Casagrande08), 3840K(Lepine13), 3900K(Morales08), 4003+-85K(Gaidos14) => 3870K. GaiaEDR3: plx=48.7404+-0.0184mas, G=9.289488+-0.002766, E(Bp/Rp)=1.314, Bp-Rp=1.832388, Bp-G=0.896807, G-Rp=0.935581. G-V = 9.2895 - 9.9955 = -0.706. Mv=8.38, M_G=7.729, M_Ks=4.79. From V-Ks vs. M_Ks, the star does appear to be slightly above MS by +0.348 mag, which translates to [Fe/H]=+0.145(JohnsonApps09 calib) or [Fe/H]=+0.105(Schlaufman10 calib) Mass=0.69+-0.01Msun(Robertson13, from Delfosse00 M_K calib), [M/H] = -0.11(Casagrande11), [M/H] = 0.00+-0.15(Robertson13, from Schlaufman10 calib), [Fe/H] = +0.27(Santos17). So the star appears to probably be roughly ~Hyades metallicity perhaps [Fe/H] ~ +0.1-0.15. # Exemplars GJ 839 = LHS 3727 = G 215-20 = MCC 72 = K7: Bidelman85 *M0V: Vyssotsky43,Lee47(M0),Stephenson86,Hawley97(M0),Lepine13(M0.0),Gaidos14(M0) M0.5V: Kirkpatrick91(sec.stan.) M1V: Joy74 This is considered a M0.5V standard by Kirkpatrick, but no other reference has classified it as M0.5, but it has a half-dozen independent classifications over 7 decades in agreement on M0V. Lepine13 used multiple spectral indices which gave average subtype of -0.06. V=10.335+-0.035(Mermilliod91), B-V=1.366+-0.014(Mermilliod91), U-B=1.200(Mermilliod91), Ks=6.765+-0.027(2MASS), V-Ks = 10.335 - 6.765 = 3.57. Teff = 3635K(Alonso96), 3830K(Lepine13), 3840K(Morales08), 4059+-81K(Gaidos14) => Teff = 3835K. plx = 39.3208 0.0274 mas(GaiaDR2), Mv = 8.308+-0.035. G=9.6670, Bp-Rp=1.8059, Bp-G=0.9004, G-Rp=0.9054. G-V= 9.667 - 10.335 = -0.668. GJ 784 = HD 191949 = HIP 99701 = UGP 492 = Smethells 50 K5: Abt72 K7.0: Hawley97 *M0V: Evans57,Smithells74,Bidelman85(M0),Torres06,Gaidos14(M0) M1/2V: Houk78 M2V: Upgren72 V=7.972+-0.008(Mermilliod91), V=7.966+-0.004(Koen02), B-V=1.431+-0.010(Mermilliod91), B-V=1.453+-0.003(Koen02), U-B=1.208+-0.005(Koen02), U-B=1.183+-0.011(Mermilliod91), V-Rc=0.913+-0.005(Koen02), V-Ic=1.842+-0.005(Koen10), J=5.122+-0.023(2MASS), Ks=4.281+-0.024(flag=E). H corrupted flag D. K=4.279(McGregor94, MSSSO), K=4.265(Mould76), K=4.300_Allen83,AAO). Adopt K = 4.28. V-J = 2.85, V-Ks = 7.966 - 4.28 = 3.686. plx = 162.3212 0.0495 mas (GaiaDR2). Mv = 9.024+-0.008. G=7.2352 0.0007, Bp-Rp=1.9159, Bp-G=0.9740, G-Rp=0.9419. G-V = 7.2352 - 7.966 = -0.731. GJ 338B = HD 79211 = LHS 261 = Lalande 18115 B K7V: Bidelman85,Kirkpatrick91(sec),Hawley97,Henry02,Reid04 *M0V: Adams26,Morgan38,Roman55,Vyssotsky56(M0Vp),Stephenson86,Rojas-Ayala12(near-IR),Alonso-Floriano15 M0.5V: Joy74 M1V: Newton15(near-IR) Morgan38 notes the pair are the 2nd and 3rd brightest northern M dwarfs. This star appears to be significantly cooler than the primary and secondary K7V standards. "B" is 17" away from primary "A". Kirkpatrick91 notes that "B" is 1 subtype earlier than "A"! Note that Mermilliod91's photometry shows HD 79211 (GJ 338B) to be slightly dimmer (.05mag), slightly redder 0.009mag in B-V, and slightly redder in U-B. Interestingly, the following studies found the two components to have identical spectral types: Adams26(M0V+M0V), Morgan38(M0V+M0V), Roman55(M0V+M0V), Joy74(M0.5V+M0.5V). Stephenson86(M0V+M0V), Bidelman85(K7V+K7V). Teffs: 3695K(Jenkins09), 3769K(Milone11), 3849K(Prugniel11), 3869K(Rojas-Ayala12), 3892K(Newton15#1), 3926K(Newton15#2) => = 3860K. V= 7.697+-0.030(Mermilliod91), B-V=1.419+-0.018(Mermilliod91), U-B=1.238+-0.041(Mermilliod91). G=7.0477 0.0004, Bp-Rp=1.8529, Bp-G=0.9301, G-Rp=0.9228. Ks=4.136+-0.020(2MASS,qual=E). V-Ks = 7.697 - 4.136 = 3.561. Gaia EDR3: 7.054455+-0.002768, Bp-Rp=1.846450, Bp-G=0.904952, G-Rp=0.941498, E(BP/RP)=1.317, plx=157.8825 0.0211mas => Mv=8.69+-0.03, M_G=8.039. G-V = 7.0477 - 7.697 = -0.649. # Deprecated Standards GJ 123 = HD 19305 = BD+01_543 = StKM 2-258 K5V: Bidelman85(K5),Stephenson86,Reid95,Houk99 *K7V: Houdebine16(dK7.0) M0V: Adams26,Vyssotsky46,Roman55,Keenan85(stan),Keenan89(non-stan),Keenan99(non-stan),Newton14(stan) M1V: Joy74 I'm deprecating this one as a standard given the wide range of types (mostly K5 through M0 since 1980s), even though Keenan consistently classified it as M0V and regarded it as a standard in at least one reference (Keenan85, IAU Symposium 111). V-Ks and B-V color is more like ~K7 or slightly cooler. Despite it being a rare M0V star from Keenan, it has not appeared in any of Kirkpatrick's or Henry's lists of standards. 2nd brightest M0V star in SIMBAD after HD 79211, and it is clearly a bit bluer and hotter than the other M0V standards. Not in Keenan80 or Keenan83 or KeenanYorka85, however Keenan85(IAU Symposium 111) listed only HD 19305 (GJ 123) and HD 232979 as M0V standards. V=9.072+-0.020(Mermilliod91), V=9.055(Koen10), B-V=1.360+-0.019(Mermilliod91), B-V=1.385(Koen10), U-B=1.257(Koen10), U-B=1.240+-0.087(Mermilliod91), V-Rc=0.854(Koen10), V-Ic=1.628(Koen10). J=6.492+-0.021(2MASS), H = 5.843+-0.034(2MASS), Ks=5.646+-0.021(2MASS). V-Ks=3.409 (Koen10,2MASS). Teff= 3850K(Cesetti13), 3998+-53K(Deka-Szymankiewicz18), 3999K(Moro-Martin15), 4020+-100K(Houdebine16#1), 4053K(Leger15), 4065+-45K(Houdebine16#2), 4130K(Morales08) => = 4020K. plx = 67.8892 0.0518 mas (GaiaDR2). Mv = 8.21 (using Koen10,GaiaDR2), M_Ks = 4.805 +- 0.021 (2MASS,GaiaDR2). Gaia DR2: plx=67.8892 0.0518 mas. GJ 763 = HD 184489 = HIP 96285 = K5V: Lee47(K5),Reid95 K7: Bidelman85 K8V: Gray03 *M0V: Vyssotsky46,Kirkpatrick91(sec.stan.),Gaidos14(M0),M0.0V(Passegger19) sdM0.0: Schweitzer19 M0.5V: Joy74 M1V: Adams26 sdM1:: Alonso-Floriano15 Wide range of modern types from K5 to M1. [Fe/H] = -0.16(Luck17), [Fe/H] = -0.17+-0.16(Schweitzer19), [Fe/H] = -0.57(Houdebine16), [Fe/H] = -1.50(Alonso96). V=9.326(Koen10), B-V=1.381(Koen10), U-B=1.210(Koen10), V-Rc=0.851(Koen10), V-Ic=1.626(Koen10), Ks=5.918+-0.017(2MASS). V-Ks = 9.326 - 5.918 = 3.408. GJ 172 = HD 232979 = BD+52_857 K7: Cannon27,Bidelman85,Crifo10 K7.7: Mann15(note: not K8,K9 in this work) K8V: Cowley67(K8V(e)),Montes01(K8V),Cenarro01,Neves13 *M0V: 1956PMcCO..13a....B,KeenanMcNeil76(stan),Keenan80,Keenan85,Turnshek85(stan,dM0),Corbally86(stan,Keenan80),Gray03,Gaidos14 M0.5V: Keenan89(stan),Montes98 M1V: Adams35,Joy74 M2V: Adams26,Vyssotsky56(M2Vp) Probably not great as a standard given that Keenan moved it from M0V to M0.5V (a shame as this was the only M0V standard in KeenanMcNeil76). It has not appeared in Kirkpatrick or Henry papers, and it is not listed in Dwarfarchives [as of 5/28/2017]. Would be nice to see a classification compared to Kirkpatrick91 standards. Oddly, Lepine13 calls it "G/K". One of the brightest (2nd?) "K7" stars classified by Cannon that ended up being a dwarf. One of only 2 K8V stars classified by Cowley67. WDS lists it as 11" binary. [Fe/H]=-0.11+-0.08(Mann15). Teffs: 3926+-96K(Gaidos14), 3929+-60K(Mann15) => = 3928K. GJ 809 = HD 199305 = HIP 103096 = LHS 3595 (J2053+6209) M0V: Kirkpatrick92PhD,Henry94,Henry02,Kirkpatrick12 M0.5V: Hawley97 *M1: Gaidos14,Lepine13(M1.0),Mann15 M4: Lee47 M2V: Keenan46 Kirkpatrick12 lists the primary as "M0 V" (joint type, cites Kirkpatrick92(PhD)) and calls the companion "M? V?" (cites "this paper"). However, four recent surveys (Gaidos, Lepine, Hawley) place it 0.5-1 subtype later. Lepine13 used multiple spectral indices which gave M0.84. V=8.55(HIP), V=8.554+-0.037(Mermilliod91), B-V=1.483+-0.012(HIP), B-V=1.483+-0.012(Mermilliod91), V-I=1.97+-0.07(HIP), U-B=1.237+-0.009(Mermilliod91), J=5.429+-0.029(2MASS), Ks=4.618+-0.024(2MASS), V-J=3.121(HIP,2MASS), (V-Ks)=3.932(HIP,2MASS). Teff= 3400K(Lepine13), 3630K(Alonso96), 3646+-53K(Ramirez05), 3692+-22K(Boyajian12), 3715+-14K(Pecaut13), 3720+-50K(Woolf05), 3791+-60K(Mann15#1), 3843K(Gaidos14), 3846+-37K(Mann15) => Teff = 3715K. 3791K. R=0.54Rsun(Gaidos14), R=0.515+-0.01 Rsun(Mann15), mass=0.58Msun(Gaidos14), Mass = 0.546+-0.013 Msun (Mann15). plx=142.0341+-0.0305mas(GaiaDR2). GJ 686 = LHS 452 = G 170-55 = HIP 86287 (J1737+1835) M0V: Stephenson86("M0:V"),Henry94,Henry02 M0.5: Bidelman85 M1V: Joy74,Hawley97,Rojas-Ayala12 M1.2: Mann15 *M1.5V: Lepine13 M2: Gaidos14 [last updated 8/29/2017] I've deprecated this star as a standard as subsequent works have all consistently found later types (M1,M1.5,M2), and its colors (V-Ks=4.05, B-V=1.53) are sufficiently red that they appear typical for M1-M2 stars. I've adopted M1.5V from Lepine13 as representative for the recent surveys. V=9.62(HIP), V=9.612+-0.004(Mermilliod91), B-V=1.530+-0.015(HIP), B-V=1.569+-0.074(HIP), V-I=2.30+-0.11(HIP), U-B=1.080(Mermilliod91), J=6.360+-0.023(2MASS), H=5.790+-0.020(2MASS), Ks=5.572+-0.020(2MASS), V-J=3.26(HIP,2MASS), (V-Ks)=4.048(HIP,2MASS). Using 2MASS JHKs photometry and Casagrande08 relations, mbol = 8.063+-0.019, BCv = mbol - V = 8.063 - 9.612 = -1.549, BC_Ks = 8.063 - 5.572 = 2.491. plx = 123.67+-1.61 mas(vanLeeuwen07) => Mv = 10.07, M_Ks = 6.033, Mbol = 8.52+-0.03, logL = -1.51+-0.01. Teffs: 3524K(V-K=>Casagrande08 calibration), 3560K(Lepine13), 3657K(Gaidos14,Mann15), 3680K(Morales08), 3686K(V-K=>Mozurkewich03 calibration) => median Teff ~ 3657K. R=0.424+-0.015Rsun(Mann15,Yee17), M=0.442+-0.044Msun(Mann15), [Fe/H]=-0.25+-0.08(Mann15). GJ 701 = LHS 3356 (J1805-0301) K4/5V: Houk99(q=4) M0V: Henry94,Henry02(stan) M0.5: Bidelman85 *M1V: Hawley97,Gaidos14,Dieterich14 M1.3: Mann15 M1.5V: Cowley82 M2V: Upgren72,Joy74 [last updated 5/28/2017] Published types range from K4-M2. We had considered this star our main M0V spectral standard in Pecaut13, but I'm now convinced that this star should be considered ~M1V when compared to other early M standards. This appears to be among the coolest of Henry's M0V standards (by Teff and colors), and a look at Fig. 1 of Henry94 showing red spectra of M dwarf standards does show negligible difference in appearance of GJ 701 (as M0V standard; V-Ks=4.064, B-V=1.508+-0.014) and GJ 514 (M1V standard; V-Ks=4.014, B-V=1.497+-0.013), and indeed their optical/near-IR colors are indistinguishable. Given that GJ514's pedigree as M1V appears much more solid, and given that all other works (ignoring the q=4 Houk type) have considered GJ 701 later than M0V, I provisionally deprecate this star as a standard. Kirkpatrick12 cites the Henry94 M0V type. V=9.37(HIP), V=9.377+-0.020(Mermilliod91), B-V=1.510+-0.017 (Mermilliod91), B-V=1.508+-0.014(HIP), B-V=1.414+-0.022(APASS/DR9), V-I=2.06(HIP), U-B=1.206+-0.012(Mermilliod91), J=6.161+-0.019(2MASS), H=5.571+-0.040(2MASS), Ks=5.306+-0.021(2MASS), V-J=3.209(HIP,2MASS), (V-Ks)=4.064(HIP,2MASS). Using 2MASS JHKs and Casagrande08 calibration: mbol = 7.819+-0.013 => BCv = mbol - V = 7.819 - 9.377 = -1.558, BC_Ks = mbol - Ks = 7.819 - 5.306 = 2.513. Plx = 128.89+-1.43 mas(vanLeeuwen07) => Mv = 9.93+-0.03, M_Ks = 5.86+-0.03, Mbol = 8.37+-0.03, logL = -1.45+-0.01. Teffs: 3493+-50K(Houdebine10), 3614+-60K(Mann15), 3630+-30K(Woolf05), 3680K(Morales08), 3710+-101K(Gaidos14#1), 3733+-68K(Gaidos14#2) => median Teff = 3655K. Mass = 0.489+-0.016 Msun(Jenkins09). GJ 617A = HD 147379A = Cin 18 2184 K7: Bidelman85 *M0V: Adams26,Vyssotsky46,JM53,Joy74,Montes01,Cenarro09,Lepine13(M0.0V),Alonso-Floriano15 M1-Ve: Keenan89 M1.0V: Lafloret11(CARMENCITA),Gaidos14(M1) M2: Lee47 Probably M0V-M1V, but not sure where to put it. Probably not the best choice of standard. JohnsonMorgan53 considered it a M0V standard, but Keenan considered it 0.75 subtype later. No published classifications by Kirkpatrick or Henry. # Other Stars GJ 79 = HD 11507 = CD-23 693 K5/M0V: Houk88 K7: Bidelman85,Reid95 K9V: Munch44,Gray06(K9Vk) *M0V: Adams35,Gaidos14(M0),Torres06 M0.2: Mann15 M1V: Adams35,Upgren72 M1.5V: Joy74 M2V: Vyssotsky43 GJ 488 = HD 111631 = Cin 18 1633 = G 14-6 K6Ve: Popper43 K7V: Wilson62,Bidelman85,Stephenson86,Reid95 K7.9: Mann15 *M0V: Adams26,Lee47(M0),Vyssotsky56,Upgren72,Gaidos14 M0.5V: JM53(non-standard),Joy74 Not good agreement on types. Mann15 has it as "K7.9", with K7 to M0 being one step, so essentially M0. (B-V)=1.412+-0.012(Mermilliod91), V=8.491+-0.019(Mermilliod91), U-B=1.258+-0.009(Mermilliod91). GJ 519 K5: Lee47 K7: Bidelman85 K7.5V: Lepine13 *M0V: Gaidos14 M1V: Joy74 M2V: Vyssotsky43 Non-standard. GJ 825 = Lacaille 8760 = HD 202560 = AX Mic = UGP 518 = LHS 66 (J2117-3852) K7.0: Hawley97(Kirkpatrick12) K9.0V: Isaacson17 Map: Cannon24(Skiff converts to "M1/3V") M0V: Evans57(M0Ve),Upgren72,Bidelman85(M0),Torres06 *M0.5V: Walker83 M1V: Adams26,Joy74,Keenan89(non-stan),Gaidos14(M1) M1/2V: Houk82 Lac 8760 = Brightest southern M dwarf (V=6.7), and the one "pure" M1V in Keenan89 (although not a standard, although there are two M1V variants). In the final volume of HD catalog (Cannon24), the star stood out sufficiently that Cannon mentions it on page 4 in an overview of the properties of stellar spectra ("lines of low temperature are abnormally intense"), and she classified it as "Map" (i.e. "Ma" "p" for peculiar), and remarked "Proper motion, 3".46, 249.4 [deg]. The spectrum shows strong characteristics of low temperature. Line 4227 is very strong. The titanium oxide bands are only faintly seen." (HD 202500, ptm. phot. mag. 7.9 [on blue sensitive plates]). Later in Cannon24, she lists HD 217987 (Lacaille 9352) also as "Map" and ptm. mag 7.44 and photographic magnitude 9.0, and commented "The spectrum shows the characteristics of dwarfs. Parallax 0".29, Proper motion, 7".0, 80.5 [deg]". So Cannon acknowledged that Lac 8760 and Lac 9352 were both M type and nearby dwarfs, with Lac 8760 being ~1 mag brighter of the two. Lac 8760 has a wide range of classifications over the past few decades, so it might not be the best choice of standard (suprising given its historical importance and brightness). Note that Joy74's M1V corresponds roughly to M0.5(+-1.0) on the Kirkpatrick91 system (see notes in M0V.txt), and Teff (below) is most similar to M0.5V-ish. Teffs: 3592K(Alonso96), 3599+-52K(Ramirez05), 3776+-80K(Gaidos14), 3796+-18K(Koleva12), 3912K(Moro-Martin15), 3930K(Morales08) => = 3786K. [Fe/H]=-0.62+-0.07(Koleva12), logg=4.55+-0.08(Kovleva12). GJ 666B = 41 Ara B = HR 6416B = HD 156274B = HIP 84720B = LHS 445 K7V: Walker83,Reid95(K7.0),Dieterich12 M0V: Evans59,Luyten79(M0),Gliese91 *M0Vp Ca-3 Cr-1: Corbally84 M0.5: Bidelman85 Raghavan10 notes that primary is Aa+Ab with 88.03d orbit, and B orbits A in 693.24y. Zakhozhaj79 lists D component that is M7V? GJ 341 = HD 304636 = HIP 45908 = LHS 2128 = CD-59 2351 = UGP 204 = NLTT 21618 = L 140-9 *M0V: 1930POPot..27b...1B,Upgren72,Reid95(M0.0) M1: Gaidos14 GJ 239 = HD 260655 = LSPM J0637+1733 K7V: Reid95 *M0V: Bidelman85(M0),Henry02,Lepine13(M0),Gaidos14(M0) M0.2: Mann15 M1V: Adams26,Lee47(M1),Joy74,Newton14(near-IR) GJ 208 = HD 245409 = HIP 26335 = TYC 709-63-1 K5: Lee47 K6V: Stephenson86 K7: Cannon31, Reid95 K7.9: Mann15 *M0V: Vyssotsky56(M0V),Lurie13(M0),Gaidos14(M0) M0.5Vke: Gray03 M1e: Stephenson75 157" common proper motion pair. Spectral types are typical messy borderline K/M case. Mann15 "K7.9" is 0.1 from M0, not K8. V=8.78(HIP), V=8.82(Mermilliod91), B-V=1.414+-0.059(HIP), B-V=1.38(Mermilliod91), U-B=1.18(Mermilliod91), Mann15: Fbol=2.04+-0.02 10pW/m2, R=0.601+-0.020Rsun, M=0.646+-0.065Msun, [Fe/H]=0.05+-0.08. Teffs: 3966+-60K(Mann15#1), 4020+-41K(Mann15#2). GaiaDR2: 87.4367+-0.0562mas, G=8.2080+-0.0012, E(BR/RP)=1.302, Bp-Rp=1.8278, Bp-G=0.9160, G-Rp=0.9117. GJ 3403 = HIP 31862 = NLTT 16863 = UGP 145 = CD-55 1514 = 2MASS J06393764-5536349 K7V: Upgren72 *M0V(k): Gray06,Gaidos14(M0) Mpec: Stock72 # Data I accessed the DwarfArchive website 2012 Dec 18 (http://spider.ipac.caltech.edu/staff/davy/ARCHIVE/index.shtml). It lists 18 "M0 V" stars classified by Kirkpatrick or collaborators. Among those are 12 Gliese and LHS stars with V,B-V photometry in Mermilliod91. Combining that with the 2MASS Ks magnitudes, I make this table and estimate robust estimates of the "mean" (based on the median, Chauvenet-clipped mean, and probit mean). Note that the Mermilliod91 Vmag for Gl270 appears to differ by ~1 mag from other values, so I adopt 10.05 for that star based on the literature review above. #Name Vmag uVmag B-V uB-V Ksmag uKsmag V-Ks uV-Ks Gl328 9.961 0.029 1.401 0.021 6.352 0.021 3.609 0.035 (deprecated standard) Gl338A 7.644 0.033 1.410 0.017 3.988 0.033 3.656 0.046 (deprecated standard, binary) Gl270* 10.05 ... 1.415 0.015 6.376 0.013 3.674 ... (standard) Gl784 7.972 0.008 1.431 0.010 4.281 0.019 3.691 0.020 [among nearest 100] GL809* 8.554 0.037 1.483 0.012 4.618 0.019 3.936 0.041 (standard) Gl686* 9.612 0.004 1.569 0.074 5.572 0.013 4.040 0.013 (standard) Gl701* 9.377 0.020 1.510 0.017 5.306 0.015 4.071 0.025 (deprecated standard) Gl519 9.070 ... 1.400 ... 5.486 0.015 3.584 ... Gl734A 9.420 ... 1.370 ... 5.893 0.013 3.527 ... Gl748.2B 11.157 ... 1.301 ... 7.780 0.017 3.377 ... Gl763 9.350 0.006 1.395 0.010 5.918 0.009 3.432 0.010 GL825 6.691 0.030 1.397 0.012 3.100 0.230 3.591 0.231 #Average ... ... 1.412 0.013 ... ... 3.642 0.058 rms=0.057 rms=0.284 # V-K vs. H-Ks for M dwarfs Throughout the M dwarfs (3.5 < V-K < 9.2), a fit to the photometry of Winters+2015 for 960 stars with good VJHK photometry yields: H-Ks = 4.8433579650605102e-002 + 4.4641549089040944e-002*(V-Ks) (3.5 < V-Ks < 9.2; rms = 0.030 mag) J-H = 6.0825393189317456e-001 + 4.7970200132622237e-002*(V-Ks) -1.8610796358879855e-002*(V-Ks)^2 + 1.5786335399504065e-003*(V-Ks)^3 [rms = 0.052] SpT V-Ks H-Ks J-H M1 4.065 0.230 0.602 M1.5 4.12 0.232 0.600 M2 4.23 0.237 0.598 M2.5 4.43 0.246 0.593 M3 4.60 0.254 0.589 M3.5 5.00 0.272 0.580 M4 5.25 0.283 0.576 M4.5 5.65 0.301 0.570 M5 5.94 0.314 0.567 M5.5 6.50 0.339 0.567 M6 7.30 0.374 0.581 M6.5 7.60 0.388 0.591 M7 8.00 0.406 0.609 M7.5 8.40 0.423 0.634 M8 8.73 0.438 0.659 M8.5 8.90 0.446 0.674 M9 9.00 0.450 0.683 M9.5 9.30 0.464 0.715 # K/M Boundary Cantrell13 adopts K/M boundaries of Mv=9.0 (based on Mv for M0.0V star from Henry06) or color cutoff of V-Ks=3.5 (based on KenyonHartmann95). Silverstein19 (GSU PhD thesis; https://scholarworks.gsu.edu/phy_astr_diss/116/) also adopts V-Ks=3.50 and notes "only a few stars classified as M dwarfs fall on the blue side of this line". This compares reasonably well against the bluest M0V standard (GJ 338A; V-K ~ 3.55), the reddest K7V standard (GJ 673; V-Ks=3.40) and the median colors adopted here for late K dwarfs: K7V(3.35), K8V(3.48), K9V(3.55). Silverstein19 offers a scientific definition for "red dwarf": "We more precisely define a red dwarf to be any main sequence star ranging from spectral type M0.0V (mass ~ 0.63 Msun) to the end of the main sequence, at roughly L2.5V (mass ~ 0.08 Msun) (Dieterich et al. 2014, Benedict et al. 2016)". In practice they selected dwarf stars with 3.50 < V-Ks < 10.5. # Latest Table of HRD Parameters (7/3/2020) SpT Teff logL Mass M0 3840 -1.192 0.57 M0.5 3770 -1.268 0.54 M1 3660 -1.392 0.50 M1.5 3610 -1.464 0.47 M2 3560 -1.540 0.44 M2.5 3470 -1.668 0.40 M3 3410 -1.772 0.37 M3.5 3260 -2.072 0.27 M4 3210 -2.200 0.23 M4.5 3110 -2.400 0.184 M5 3060 -2.520 0.162 M5.5 2940 -2.788 0.123 M6 2810 -3.012 0.102 M6.5 2730 -3.124 0.093 M7 2680 -3.188 0.090 M7.5 2630 -3.236 0.088 M8 2570 -3.284 0.085 M8.5 2420 -3.472 0.080 M9 2380 -3.520 0.079 M9.5 2350 -3.572 0.078