G2V Garrison94 calls Sun the G2V anchor standard, and MK73 calls Sun (actually Jupiter IV spectrum) as the G2V dagger standard. There are numerous stars in the literature considered 'solar twins'. Although most are not considered spectral type standard stars (some are, e.g. 18 Sco), their properties are useful for constraining the Sun-as-a-star parameters that may be difficult to measure from Earth (e.g. Sun's estimated visible/IR colors). Although some are lacking modern spectral types (some have few if any, or some low quality one from low-res spectra from photographic plates from >5 decades ago), their combination of parameters (Teff/logg/[Fe/H]) measured with high SNR, high res spectra are so close to that of the Sun that they should probably be considered G2Vs. I list several of them below under separate category of 'solar twins'. MK43 standard: lam Aur - G2IV-V JM53 standard: Sun - G2V 16 Cyg(pr) (= 16 Cyg A) - G2V HR 483 (= HD 10307) - G2V Morgan65 standard: Sun - G2V Morgan71 standard: Sun - G2V MK73 dagger standard: Sun - G2V Houk75 standard: bet Com - G2V (adopted G2V, but notes MK73 call it G0V dagger) Cowley76 standard: HR 483 - G2V KeenanMcNeil76 stan.: Sun (moon) - G2V Keenan80 standard: Sun ("defining zero point") Gl 182.1 (=HD 31966) - G2IV-V 20 LMi (=HD 86728) - G2Va Hdel1 18 Sco - G2Va Keenan83 standard: Sun - G2V 18 Sco - G2Va VB 64 (=HD 28099) - G2+V [Hyades member] Keenan85 standard: Sun - G2V 9 Cet (=HD 1835) - G2V VB 64 (=HD 28099) - G2+V [Hyades member] HD 76151 (=HR 3538) - G2V 18 Sco (=HD 146233) - G2Va Keenan88 standard: Sun - G2V HD 76151 - G2V xi UMa B - G2V 18 Sco (=HD 146233) - G2Va HD 45184 - G2Va Gray89 standard: Sun [Jupiter IV] - G2V Keenan89 standard: VB 64 (=HD 28099) - G2+V HD 45184 (=HR 2318) - G2Va HD 76151 (=HR 3538) - G2V xi UMa B (=HD 98230) - G2V 18 Sco - G2Va Strassmeier90 stan: Sun(sky) - G2V Garrison94 anchor: Sun - G2V Keenan99 standards: HD 45184 (=HR 2318) - G2 Va (primary standard) HD 76151 (=HR 3538) - G2 V (primary standard) HD 2141 - G2 V (secondary standard) VB 64 (=HD 28099) - G2+ V * (secondary standard) HD 44594 (=HR 2290) - G2 Va (secondary standard) GrayNstars standard: Sun (Jupiter IV & Moon) HR 3538 (=HD 76151) - G2V After the Sun, RECONS lists Alf Cen A (GJ 559A; J1439-6050) as the nearest G2V. Skiff08 flags three stars as G2V MK standards, all from Keenan89: HD 146233 (G2Va), HD 45184 (G2Va), and HD 76151 (G2V). JohnsonMorgan53 listed 3 G2V standards: Sun, 16 Cyg A, and HR 483 (HD 10307)... however, Keenan later considered 16 Cyg A to be G1V, and HR 483 to be G1.5V. So the only one of the JohnsonMorgan53 G2V standards to "survive" to Keenan's system of G-type standards was the Sun! There are differences between what Gray and Houk consider G2V stars. For example, Gray06 contains 24 stars classified as "G2 V" (removed all variants regarding metallicity or intermediate temperature types and/or luminosity classes). In the Hipparcos catalog (mostly Houk classifications), these 24 stars are classified as: 1 G1Vs, 3 G2Vs, 3 G3Vs, 1 G3/5V, 3 G5IV-Vs, 12 G5Vs, and 1 G8IV+... . i.e. ~1/8th agree on "G2V", and more than half are considered G5 V or IV-V. The three stars where the Gray and Hipparcos type agreed *all* were cited as reference 'X' - i.e. SIMBAD and uncited references. HIP 15330, HIP 71683, HIP 98959. The majority of the Houk types listed in the Hipparcos catalog for the Gray06 "G2 V" stars were either G3V or G5V. Gray01/03/06 list 48 nearby G2V stars. Median HIP colors: (G2V) = 0.647 (+-0.003 sem, +-0.035 stdev; N=48) (G2V) = 0.706 (+-0.005 sem, +-0.024 stdev; N=48) For G2V Hipparcos stars within 75pc, with parallax S/N > 8, and within 1 mag of the MS (N=223) (these are dominated by Houk spectral types, which seem to be slightly earlier/hotter on average than Gray's G2Vs): (G2V) = 0.617 (+-0.003 sem, +-0.032 stdev; N=223) (G2V) = 0.683 (+-0.004 sem, +-0.027 stdev; N=223) (G2V) = 1.148 (+-0.006 sem, +-0.075 stdev; N=223) (G2V) = 1.429 (+-0.007 sem, +-0.096 stdev; N=223) (G2V) = 1.504 (+-0.006 sem, +-0.095 stdev; N=223) (G2V) = 0.282 (+-0.003 sem, +-0.034 stdev; N=223) (G2V) = 0.078 (+-0.002 sem, +-0.026 stdev; N=223) (G2V) = 0.679 (+-0.003 sem, +-0.044 stdev; N=223) (G2V) =-0.071 (+-0.001 sem, +-0.015 stdev; N=223) (G2V) = 2.118 (+-0.009 sem, +-0.118 stdev; N=223) (B-V)(G2V) = 0.543 ; BakisEker22 (G2V) = 0.617 ; 223 HIP d<75pc (+-0.003 sem, +-0.032 stdev) (mostly Houk types) (B-V)(G2V) = 0.62 ; KenyonHartmann95 (B-V)(G2V) = 0.623 (+-0.010 sem,+0.033 stdev); 35 ARICNS G2V stars (B-V)(G2V) = 0.626 ; ter. stan. HD 45184 (B-V)(G2V) = 0.63 ; Fitzgerald70, Morgan71 (B-V)(G2V) = 0.63 ; SchmidtKaler82 (B-V)(G2V) = 0.633 ; non-stan. alf Cen A (B-V)(G2V) = 0.64 ; JohnsonMorgan53 (B-V)(G2V) = 0.64 ; median CATSUP d<30pc (N=29) (B-V)(G2V) = 0.640 ; solar twin HD 216008 = HIP 112730 (B-V)(G2V) = 0.640 ; median SIMBAD G2V d<25pc (N=21) (B-V)(G2V) = 0.642 ; solar twin HD 195034 = HIP 100963 (B-V)(G2V) = 0.647 ; solar twin HD 101364 = HIP 56948 (G2V) = 0.647 ; 48 Gray01/03/06 G2V (+-0.003 sem, +-0.035 stdev) (B-V)(G2V) = 0.647 ; solar twin HD 88072 = HIP 49756 (B-V)(G2V) = 0.65 ; Johnson66 (B-V)(G2V) = 0.650 ; trend among standards and solar twins below, interp to [Fe/H]=0.00 (B-V)(G2V) = 0.652 ; sec. stan. 18 Sco (B-V)(G2V) = 0.653 ; pri. stan. Sun (Ramirez12 color) (B-V)(G2V) = 0.655 ; Keenan G2V standard xi UMa B (B-V)(G2V) = 0.656 ; solar twin HD 138573 = HIP 76114 (B-V)(G2V) = 0.660 ; ter. stan. HD 44594 (B-V)(G2V) = 0.661 ; sec. stan. HD 76151 (B-V)(G2V) = 0.665 ; solar twin HD 124523 = HIP 69645 => adopt (B-V)(G2V) = 0.650 *** [updated 10/10/2020] [EEM update 5/18/2017; I've decided to adopt B-V(G2V) = B-V(Sun) = 0.650. See notes at: http://www.pas.rochester.edu/~emamajek/sun.txt. This value is well supported by the new precise estimate of the solar colors by Ramirez et al. (2012), and the median colors of G2V field stars classified by Gray and collaborators. 10/10/2020 update: trend of standards and solar twins below interp to [Fe/H]=0.00 also yields 0.650, i.e. it is repeatable. No need to update colors. ] It is possible that the use of HD 76151 as a G2V standard is what has skewed the mean B-V for G2V stars in the Gray Nstars sample to be somewhat redder than that for the other standards. => adopt (U-B)(G2V) = 0.133 => adopt (V-I)(G2V) = 0.710 => adopt (V-R)(G2V) = 0.363 => adopt (R-I)(G2V) = 0.350 => adopt (V-J)(G2V) = 1.199 => adopt (V-H)(G2V) = 1.491 => adopt (V-Ks)(G2V) = 1.564 => adopt (H-Ks)(G2V) = 0.073 => adopt (J-H)(G2V) = 0.293 (G-V)(G2V) = -0.140 ; from trend for B-V=0.650 (G-V)(G2V) = -0.151 ; median for Kervella19 d<25pc G2V sample (G-V)(G2V) = -0.154 ; HD 207129 PM* G2V (G-V)(G2V) = -0.156 ; HD 76151 PM* G2V (G-V)(G2V) = -0.160 ; HD 189567 PM* G2V (G-V)(G2V) = -0.160 ; solar twin HD 101364 = HIP 56948 (G-V)(G2V) = -0.162 ; G dwarf trend for G2V (G-V)(G2V) = -0.164 ; ter. stan. HD 76151 (corrected) (G-V)(G2V) = -0.164 ; HD 181321 PM* G2V (G-V)(G2V) = -0.165 ; HD 38858 PM* G2V (G-V)(G2V) = -0.166 ; HD 12846 PM* G2V (G-V)(G2V) = -0.167 ; HD 190771 PM* G2V (G-V)(G2V) = -0.167 ; HD 199288 PM* G2VFe-1.0 (G-V)(G2V) = -0.167 ; solar twin HD 88072 = HIP 49756 (G-V)(G2V) = -0.167 ; solar twin HD 216008 = HIP 112730 (G-V)(G2V) = -0.168 ; solar twin HD 195034 = HIP 100963 (G-V)(G2V) = -0.169 ; HD 102365 PM* G2V (G-V)(G2V) = -0.174 ; solar twin HD 124523 = HIP 69645 (G-V)(G2V) = -0.175 ; solar twin HD 138573 = HIP 76114 (G-V)(G2V) = -0.177 ; HD 210918 PM* G2V (G-V)(G2V) = -0.205 ; HD 76932 PM* G2VFe-1.8CH-1 => adopt (G-V)(G2V) = -0.165 [updated 11/1/2020] (Bp-Rp)(G2V) = 0.8364 ; solar twin HD 124523 = HIP 69645 (Bp-Rp)(G2V) = 0.829 ; ter. stan. HD 76151 (corrected) (Bp-Rp)(G2V) = 0.8237 ; solar twin HD 138573 = HIP 76114 (Bp-Rp)(G2V )= 0.823 ; color trend for B-V=0.650 (Bp-Rp)(G2V) = 0.8156 ; solar twin HD 101364 = HIP 56948 (Bp-Rp)(G2V) = 0.814 ; solar twin HD 88072 = HIP 49756 (Bp-Rp)(G2V) = 0.8121 ; solar twin HD 216008 = HIP 112730 (Bp-Rp)(G2V) = 0.8117 ; solar twin HD 195034 = HIP 100963 (Bp-Rp)(G2V) = 0.8085 ; HD_98618 (Bp-Rp)(G2V) = 0.8081 ; 18_Sco (Bp-Rp)(G2V) = 0.867 ; Evans18 trend for V-I= 0.710 => adopt (Bp-Rp)(G2V) = 0.815 [updated 11/22/2020] (Bp-G)(G2V) = 0.3435 ; HD_98618 (Bp-G)(G2V) = 0.3456 ; HD_216008 (Bp-G)(G2V) = 0.3461 ; HD_101364 (Bp-G)(G2V) = 0.3486 ; HD_195034 (Bp-G)(G2V) = 0.349 ; Bp-Rp=0.815, G-Rp=0.466 (Bp-G)(G2V) = 0.3511 ; HD_88072 (Bp-G)(G2V) = 0.3547 ; HD_124523 (Bp-G)(G2V) = 0.3574 ; HD_138573 (Bp-G)(G2V) = 0.3637 ; HD_76151 (Bp-G)(G2V) = 0.365 ; color trend for B-V=0.65 (Bp-G)(G2V) = 0.3720 ; 18_Sco => adopt (Bp-G)(G2V) = 0.349 [updated 11/22/2020] (G-Rp)(G2V) = 0.4361 ; 18_Sco (G-Rp)(G2V) = 0.462 ; solar twin HD 88072 = HIP 49756 (G-Rp)(G2V) = 0.4630 ; solar twin HD 195034 = HIP 100963 (G-Rp)(G2V) = 0.4656 ; HD_76151 (G-Rp)(G2V) = 0.4663 ; solar twin HD 138573 = HIP 76114 (G-Rp)(G2V) = 0.4665 ; solar twin HD 216008 = HIP 112730 (G-Rp)(G2V) = 0.4695 ; solar twin HD 101364 = HIP 56948 (G-Rp)(G2V) = 0.478 ; ter. stan. HD 76151 (corrected) (G-Rp)(G2V) = 0.4817 ; solar twin HD 124523 = HIP 69645 (G-Rp)(G2V) = 0.488 ; color trend for B-V=0.65 => adopt (G-Rp)(G2V) = 0.466 [updated 11/22/2020] (Ks-W1)(G2V) = 0.061 ; EEM trend for d<30pc for B-V=0.65 => adopt (Ks-W1)(G2V) = 0.061 [updated 12/29/2019] (U-B)(G2V) = 0.100 ; HIP d<75pc S/N>8 G2V N=107 (Mermilliod91 photometry) (U-B)(G2V) = 0.158 ; Ramirez05 color for Sun (+-0.009; line-depth ratios) (U-B)(G2V) = 0.16 ; Johnson66 (U-B)(G2V) = 0.16 ; JohnsonMorgan53 (V-Ks)(G2V) = 1.511 ; solar twin HD 195034 = HIP 100963 (V-Ks)(G2V) = 1.515 ; solar twin HD 101364 = HIP 56948 (V-K)(G2V) = 1.539 +- 0.025 ; B-V vs. V-K(Ducati/Johnson) for XHIP d<50pc G Vs (-0.1<[Fe/H]<0.1) for B-V=0.650 (V-Ks)(G2V) = 1.541 ; solar twin HD 216008 = HIP 112730 (V-Ks)(G2V) = 1.545 +- 0.02 ; Rieke08 (NStars interp to 5778K) (V-Ks)(G2V) = 1.547 ; solar twin HD 88072 = HIP 49756 (V-Ks)(G2V) = 1.548 +- 0.043 ; B-V vs. V-Ks for XHIP d<50pc G Vs (-0.1<[Fe/H]<0.1) for B-V=0.650 (V-Ks)(G2V) = 1.552 +- 0.024 ; ter. stan. HD 76151 (V-Ks)(G2V) = 1.560 +- 0.008 ; pri. stan. Sun (Casagrande11) (V-Ks)(G2V) = 1.564 ; V-Ks vs. B-V polynomial fit for B-V = 0.65 (V-Ks)(G2V) = 1.570 ; solar twin HD 138573 = HIP 76114 (V-Ks)(G2V) = 1.571 +- 0.007 (+-0.035 1sig) ; 23 Gray06 "G2 V" stars (g-r)(G2V) = 0.474 ; Jordi06 (V-R)=>(g-r) for V-R=0.363 (g-r)(G2V) = 0.479 ; Bilir05 (B-V)=>(g-r) for B-V=0.650 => adopt (g-r)(G2V) = 0.476 [updated 10/10/2020] Teff(G2V) = 5710 K ; GrayCorbally94 Teff(G2V) = 5748 K ; 23 Teffs for "G2 V" stars in Gray06 Teff(G2V) = 5750 K ; GrayCorbally09 Teff(G2V) = 5700 K ; Teff from smoothed SpT(Teff) trend Teff(G2V) = 5760 K ; Teff for d<30pc [Fe/H]=+-0.1 dex dwarfs from Hinkel17 for B-V=0.65 Teff(G2V) = 5772+-1 K ; Sun (Mamajek12) Teff(G2V) = 5780 K ; sec. stan. HD 76151 (PASTEL/Soubiran22 ) Teff(G2V) = 5784 K ; Boyajian12 Teff(G2V) = 5785 K ; sec. stan. HD 146233 (18 Sco) (PASTEL/Soubiran22 ) Teff(G2V) = 5819 K ; ter. stan. HD 44594 median Teff Teff(G2V) = 5859 K ; deprecated stan. HD 45184 Teff(G2V) = 5860 K ; Schmidt-Kaler82 => adopt Teff(G2V) = 5770 K (logT = 3.761) [last updated 11/22/2018] I have calibrated the BCv scales of Code76,Balona94,Flower96,Schmidt-Kaler82,Casagrande06/08/10 to precisely BCv = -0.085 for Teff=5772 K and/or G2V, calibrated to Casagrande18 BC data but calibrated to IAU2015 system. BCv(G2V) = -0.085 mag ; Casagrande18(Teff=5772K,logg=4.5,IAU2015 system) BCv(G2V) = -0.085 mag ; exemplar alf Cen A (see below) BCv(G2V) = -0.090 mag ; Chen19 PARSEC Teff=5772K,logg=4.5,solar (predicted Mv(Sun)=4.82975) so may recalibrate the other BC values => adopt BCv(G2V) = -0.085 mag [last updated 8/29/2019] Note that Bakis & Eker (2022; https://arxiv.org/abs/2208.04110) recently list values for G2V stars BCv(G2V)=+0.078, Teff(G2V)=5888K, and (B-V)o=0.543, all of which appear to be severely at odds with real values for G2V stars like the Sun. Real Sun-like G2V stars have (B-V) ~ +0.65 (see tabluated values for G2V standards and solar twins above), and the typical Teff for G2V standard stars and solar twins is unsurprisingly that of the Sun (~5772K; again, see compilation of G2V standards and solar twins above). Their BCv(G2V) value appears to be off by ~0.16 mag if used in conjunction with IAU 2015 scale, and would lead to systematically incorrect bolometric luminosities. The Bakis & Eker BCv(G2V) value, when combined with the equation for BC values (BC_band = Mbol - M_band) and the IAU 2015 Resolution nominal Sun values (absolute Mbol=4.74, apparent mbol=-26.832) would lead to *predictions* of the Sun's absolute Johnson V magnitude to be Mv = 4.662 (= 4.74 - 0.078 = Mbol - BCv) and apparent Johnson V magnitude to be V = -26.91 (= -26.832 - 0.078 = mbol - BCv). Compare these predictions to the estimated solar values from Torres10/2010AJ....140.1158T (V_sun = -26.76+-0.03, Mv_sun = 4.81+-0.03), i.e. they are off by ~0.15 magnitude! So I would not recommend adopting the Bakis & Eker (2022) BCs at this time as they seem to have a large systematic (~0.15-0.16 mag) for Sun-like stars. Mv(G2V) = 4.07 mag ; Wegner07 [highly discrepent] Mv(G2V) = 4.7 mag ; Schmidt-Kaler82 Mv(G2V) = 4.7 mag ; GrayCorbally09 Mv(G2V) = 4.78 mag ; median SIMBAD G2V d<25pc (N=21) Mv(G2V) = 4.79 mag ; B-V=0.650 => Mv(Wright05) Mv(G2V) = 4.79 mag ; median XHIP G2V d<20pc Mv(G2V) = 4.80 mag ; Gray01/03/06 dwarfs, xHIP B-V/Mv, Gaspar16 |[Fe/H]|<0.05 "solar": fit for B-V=0.65 Mv(G2V) = 4.81 mag ; Gray01/03/06 dwarfs, xHIP B-V/Mv, Gaspar16 |[Fe/H]|<0.05 "solar": fit for B-V=0.653 Mv(G2V) = 4.825 mag ; Sun for Mbol=4.74(IAU2015), BCv=-0.085. Mv(G2V) = 4.83 mag ; B-V=0.650 => EEM fit to SIMBAD dwarfs d<25pc Mv(G2V) = 4.85 mag ; CATSUP -0.1 < [Fe/H] < 0.1 d<30pc for B-V=0.650 Mv(G2V) = 4.90 mag ; V-Ks=1.56 for EEM poly fit to SIMBAD d<25pc (1/2022) (M_Ks=3.34) => adopt Mv(G2V) = 4.80 mag [updated 9/26/2020] => adopt M_G(G2V) = 4.635 mag [updated 12/10/2020] (Mv=4.80, G-V=-0.165) => adopt M_Ks(G2V) = 3.236 mag [updated 12/30/2020] (Mv=4.80, V-Ks=1.564) logL(G2V) = 0.010 dex ; Mv=4.80, BCv=-0.085 => Mbol = 4.715 logL(G2V) = 0.000 dex ; Sun => adopt logL(G2V) = 0.010 dex [last updated 9/26/2020] => adopt Mbol(G2V) = 4.715 mag [last updated 9/26/2020] Rad(G2V) = 1.012 Rsun ; logL = 0.010, Teff=5770K => adopt Rad(G2V) = 1.012 Rsun [updated 9/26/2020] Mass(G2V) = 1.009 Msun ; EEM fit to ML for logL=0.00 Mass(G2V) = 1.003 Msun ; Eker18 ML calibration for logL=0.00 Mass(G2V) = 1.00 Msun ; pri. stan. Sun Mass(G2V) = 0.98 Msun ; sec. stan. 18 Sco => adopt Mass(G2V) = 1.00 Msun [updated 9/26/2019] logg(G2V) = 4.47 ; N=23 loggs for Gray06 "G2 V" stars logg(G2V) = 4.44 ; Sun logg(G2V) = 4.43 ; pri. stan. 18 Sco (PASTEL/Soubiran22) ### No Standards MK43 and Wilson62 do not list a G2V standard. ### Primary Standard Sun = GJ 0 *G2V: JM53,Morgan65,Morgan71,MK73(moon,dagger),Keenan76,Keenan80,Keenan83,Keenan85,Strassmeier90,Keenan91,Garrison94,GrayNstars,GrayCorbally14 G2V anchor standard according to Garrison94. Just don't stare at it. Authors usually mention using a spectrum of either the moon or one of Jupiter's satellites. For discussion on spectral type of Sun, see Keenan 1991 (PASP, 103, 642; 1991PASP..103..642K) and Morgan & Keenan 1939 (PASP, 51, 355). While the integrated spectrum of the Sun is G2V, spectra of different regions of the Sun from the center to the limb yield ~G1 through K0: Morgan & Keenan (1939): http://adsabs.harvard.edu/abs/1939PASP...51..355M. Keenan91 reported time series spectroscopy of the solar spectrum, and found that "Although these observations do not rule out the possibility that the occasional white-light flares might produce an observable effect, such flares are so rare that for all practical purposes the spectral type of the Sun can be taken as constant at G2 V." GrayCorbally14's program MKCLASS automatically classified the Sun's spectrum (Kurucz84 solar flux atlas smoothed to 1.8A resolution) as "G2V" when the S/N > 20. At S/N=10, it classified the Sun as G3V (Quality=good) and at S/N=5 was able to discern F8-G8V (Quality=Fair-poor). IAU (2015) Nominal solar values: Teff=5772K, Rad=695700km, irradiance(1au)=1361 W/m2, Mbol=4.74, mbol=-26.832. Chen19 PARSEC Teff=5772K, solar mix, logg=4.44 => Mv(Sun) = 4.830(predicted), BCv=-0.090(Maiz-Appellanix06 calibration) ### Secondary Standards HD 146233 = HR 6060 = 18 Sco = HIP 79672 G1V: Adams35, Cowley67 *G2V: Harlan74, Cowley79, KeenanYorka85(G2Va),Keenan88(G2Va, stan), Gray03 G3: Bidelman85 Well-studied "solar twin", and as such can probably be considered a strong secondary G2V standard. V=5.49(HIP), V=5.49(Johnson66), V=5.495+-0.012(Cousins71), V=5.500(Hauck97), V=5.496+-0.006(Hauck97*), V=5.503+-0.015(Mermilliod91), V=5.497314(GaiaDR3/synth) [in great agreement with measured], Bt=6.298+-0.005(HIP), Vt=5.562+-0.004(HIP), Bt-Vt=0.736+-0.006(HIP), B-V=0.652+-0.009(HIP,Mermillioid91), B-V=0.65(Johnson66), B-V=0.645+-0.006(Cousins71), U-B=0.17(Johnson66), U-B=0.18(Cousins71), U-B=0.174+-0.017(Mermilliod91), V-Ic=0.69+-0.02(HIP), Hp=5.6265+-0.0005(HIP). PASTEL median parameters: Teff = 5795+-9K, [Fe/H]=0.037+-0.007, logg=4.44+-0.01, so star is only 23+-9K hotter and 0.037+-0.007 dex more metal-rich, so remarkably close to the Sun. PASTEL 2022 (Soubiran22) averages: Teff=5785+-12K(N=43), logg=4.43+-0.02(N=37), [Fe/H]=0.03+-0.01(N=36), hence the Teff and logg is statistically indistinguishable from Sun, and the metallicity is only 3sigma higher, but basically ~solar. plx = 71.94+-0.37mas(HIP2), plx=70.7675+-0.1119mas(GaiaDR2), plx=70.7371+-0.0631mas(GaiaDR3) => Dist=14.1335+-0.0126 pc, (m-M)o=0.751+-0.002. GaiaDR2: G=5.3026 0.0018 => corrected Gcor=5.331, E(BR/RP)=1.157, Bp-Rp=0.8081, Bp-G=0.3720, G-Rp=0.4361 => corrected via Evans18 (Bp-Rp)(corr)=0.808, (Bp-G)(corr)=0.343, (G-Rp)(corr)=0.465. Unfortunately all the 2MASS photometry is corrupted (flags C and D). WISE bands 1 and 2 bad in 2012 & 2013 catalogs, but W3=3.994+-0.013(Cutri13), W4=3.956+-0.024(Cutri13). SED fit and luminosity: using VOSA to fit to 25 photometric datapoints, the best fit SED I could derive was (ignoring 2MASS JHKs(poor), IRAS 60/100um): BT-Settl-CIFIST model with Av=0(constrained), Teff=5600K, logg=4, [M/H]=0, log(L/Lsun)=0.0402+-0.0021 dex, L=1.097+-0.005234 Lsun (surprisingly small error of 0.48%, i.e. probably unrealistically smaller than absolute spectrophotometry calibration ~<1-1.5%). ### Tertiary Standards HD 76151 = HR 3538 *G2V: Keenan85,Keenan88,Keenan99,Gray01,GrayNstars(stan) G3V: Popper43,Joy47,Keenan80,Keenan83 G3/5V: Houk99(q=2) G5V: Harlan74 At least Keenan & Gray agree, although Keenan switched it from G3V (1983) to G2V (1985), then retained it as G2V in later works. B-V = 0.661+-0.012(HIP), B-V=0.666+-0.013(Mermilliod91), U-B=0.212+-0.014(Mermilliod91), V=5.999+-0.010(Mermilliod91), V=5.999(Hauck90), V=6.01(HIP), V=6.008+-0.005(Hauck97). Very well-studied spectroscopically. Not in Washington Double Star catalog, and in Nidever02 as stable RV star (rms < 100 m/s). PASTEL/Soubiran22 mean values: Teff=5780+-9K(N=32), logg=4.49+-0.02(N=27), [Fe/H]=+0.10+-0.01(N=28), so Teff is statisticaly indistinguishable from Sun (5772), and the star is just slightly more higher surface gravity (+0.05 dex) and metal-rich (+0.10 dex). 2MASS JHK flags are EDA. J=4.871+-0.037(flag=E,2MASS), H=4.625+-0.276(flag=D,2MASS), Ks=4.456+-0.023(flag=A,2MASS). V-Ks = (6.008+-0.005) - (4.456+-0.023) = 1.552+-0.024. GaiaDR2: plx=59.3469+-0.0447mas, G=5.8315+-0.0007, E(BR/RP)=1.179, Bp-Rp=0.8293, Bp-G=0.3637, G-Rp=0.4656 => corrected via Evans18 => G(corr)= 5.844, Bp(corr)=6.195, Rp(corr)=5.366, (Bp-Rp)(corr)=0.829, (Bp-G)(corr)=0.351, (G-Rp)(corr)=0.478. G-V = 5.844 - 6.008 = -0.164. ### Select Solar Twins These are stars with combinations of Teff, logg, [Fe/H] which are almost identical to that of the Sun. i.e. Teff typically within tens of K, logg and metallicity within hundreds of a dex. They do not always have modern spectral types (some are faint, V ~ 7 or 8). HD 88072 = HIP 49756 G3V: Gray03 G5V: Houk99 Classified G3V by Gray but its Teff/[Fe/H]/logg are among the closest to that of the Sun among any solar twin (and age, rotation, activity very simlar as well): Casali20 Teff=5786+-3K, logg=4.428+-0.009, [Fe/H]=+0.030+-0.003, Age = 4.7+-0.62 Gyr. V=7.52(TYC), V=7.55(HIP), V=7.542(Pickles10,SEDfit), V=7.544+-0.002(Hauck97), B-V=0.647+-0.003(HIP), B-V=0.671+-0.018(TYC), V-Ic=0.71+-0.00(HIP), Hp=7.6745+-0.0011(HIP), J=6.376+-0.020(2M), H=6.077+-0.033(2M), Ks=5.997+-0.020(2M) => V-Ks = 7.544 - 5.997 = 1.547. vsini=1.5+-0.5km/s(Marsden15), Prot=25d(Isaacson10), logR'HK=-4.993(Isaacson10). GaiaDR2: plx=27.8187+-0.0529mas, no need to correct photometry: G=7.3767+-0.0003, E(BR/RP)=1.183, Bp-Rp=0.8135, Bp-G=0.3511, G-Rp=0.4623. G-V = 7.3767 - 7.544 = -0.167. HD 98618 = HIP 55459 G5V: Roman49 *G2V: Pickles10(template) Melendez06 wrote paper just on this star as a solar twin (https://iopscience.iop.org/article/10.1086/503898/pdf): "We show that HD98618 is the second-closest solar twin and that the fundamental parameters of both HD 98618 and 18 Sco are very similar (within a few percent) to the host star of our solar system". V=7.65(HIP), V=7.658(Hauck97), B-V=0.642+-0.007(HIP), V-Ic=0.71+-0.01(HIP). 2MASS: J=6.448+-0.029(2MASS,q=A), H=6.142+-0.046(2MASS,q=A), Ks=6.061+-0.020(2MASS,q=A), V-Ks = 7.658 - 6.061 = 1.597. Ramirez12: Teff=5835K, logg=4.39, [Fe/H]=0.030+=0.022. Most precise: Spina16: Teff=5845+-10K, logg=4.42+-0.03, [Fe/H]=+0.05+-0.01. PASTEL: =5731K(N=8), <[Fe/H]>=+0.04(N=6), =4.375(N=6). 2 HD 101364 = HIP 56948 = TYC 4392-272-1 = 2MASS J11402848+6900306 G0V: 1926MeUpp..11....1L G5: 1956PMcCO..13a....B Solar twin in Melendez07 (2007ApJ...669L..89M). Tokovinin18 lists companion B 923.5" away. Slightly less active than Sun: log'RHK=-4.97(Radick18). V=8.67(HIP), V=8.70(TYC), V=8.673(Hauck97), B-V=0.630+-0.014(TYC), B-V=0.647+-0.014(HIP), V-Ic=0.71+-0.01(HIP), J=7.477+-0.019(2M), H=7.202+-0.026(2M), Ks=7.158+-0.018(2M), V-Ks = 8.673 - 7.158 = 1.515. plx=15.68+-0.67mas(HIP2). GaiaDR2: plx=16.6642+-0.0313mas, no correction to photometry needed, G=8.5135+-0.0002, E(BR/RP)=1.190, Bp-Rp=0.8156, Bp-G=0.3461, G-Rp=0.4695. G-V = 8.5135 - 8.673 = -0.1595. PASTEL: = 5793K(N=6), =4.465(N=4), <[Fe/H]>=+0.02(N=4). Spina16 seems to be best available: Teff=5793+-6K, [Fe/H]=+0.02+-0.000, logg=4.47+-0.02. HD 124523 = HIP 69645 = LTT 5588 = TYC 7812-898-1 = 2MASS J14151500-4248167 G8V+G: Houk78. One of the 3 stars with parameters closest to the Sun in Casali20, who lists Teff=5752+-3K, logg=4.458+-0.008, [Fe/H]=-0.022+-0.004, age=4.4+-0.62Gyr. Spina18 lists: Teff=5751+-3K, logg=4.435+-0.01, [Fe/H]=-0.026+-0.004. V=9.41(HIP), V=9.47(TYC), V=9.423(Hauck97), B-V=0.665+-0.004(HIP), B-V=0.649+-0.031(TYC), V-Ic=0.73+-0.00(HIP), J=8.218+-0.023(2M), H=7.879+-0.034(2M), Ks=7.855+-0.024(2M), V-Ks = 9.423 - 7.855 = 1.568. plx=12.29+-1.44mas(HIP2). GaiaDR2: plx=12.3616+-0.0643mas, G=9.2485+-0.0004, E(BR/RP)=1.193, Bp-Rp=0.8364, Bp-G=0.3547, G-Rp=0.4817, G-V = 9.2485 - 9.423 = -0.1745. PASTEL: = 5743K(N=5), =4.437(N=4), <[Fe/H]>==-0.028(N=4). HD 138573 = HIP 76114 = SPOCS 660 = TYC 932-962-1 = BD+11_2816 G0: 1948IzKry...2..103A G5IV-V: Harlan69 wG5V: Pickles10(SEDfit) Best solar twin in survey of Mahdi16 (https://www.aanda.org/articles/aa/full_html/2016/03/aa27472-15/aa27472-15.html), with Teff=5757+-10K, logg=4.42+-0.01, [Fe/H]=-0.015+-0.03. However, King05 said "While certainly solar-type stars, HIP 76114* and 77718 are a few percent less massive, significantly older, and metal-poor compared to the Sun; they are neither good solar twin candidates nor solar analogs providing a look at the Sun at some other point in its evolution". While slightly cooler by ~40K than the Sun, the other metallicity measurements have median in line with Mahdi16: [Fe/H] ~ -0.015. Spina18: Teff=5740+-3K, lgog=4.41+-0.01, [Fe/H]=-0.024+-0.003. Age = 6.6+-0.3Gyr(Lorenzo-Oliveira18), logR'HK = -4.957+-0.001(Meunier17), -5.00(Wright04), Prot = 26.0d(Wright04). V=7.22(HIP), V=7.23(TYC), V=7.232+-0.002(Hauck97), B-V=0.656+-0.007(HIP), V-I=0.72+-0.01(HIP), J=6.027+-0.021(2M), H=5.742+-0.026(2M), Ks=5.662+-0.017(2M), V-Ks = 7.232 - 5.662 = 1.570. PASTEL: =5747K(N=10), =4.42(N=8), <[Fe/H]>=-0.015(N=9). GaiaDR2: plx= 33.2950 0.0585mas, no correction needed to G,Bp,Rp: G=7.0566+-0.0003, Bp-Rp=0.8237, Bp-G=0.3574, G-Rp=0.4663. G-V = 7.0566 - 7.232 = -0.1754. HD 195034 = HIP 100963 = LTT 15980 = NLTT 49310 = SAO 88711 = SPOCS 3145 = TYC 1644-1157-1 G2V: Hinkel17(assigned based on solar twin status in YanaGalarza16) G5: HD Solar twin according to Yana Galarza16(2016A&A...589A..17Y). YanaGalarza16: Teff=5818+-4K, logg=4.49+-0.01, [Fe/H]=-0.003+-0.004, mass=1.03+0.02-0.01 Msun, age 2.0+-0.4 Gyr. V=7.09(HIP), V=7.090(Hauck97), V=7.10(TYC), B-V=0.642+-0.009(HIP), B-V=0.626+-0.009(TYC), V-Ic=0.71+-0.01(HIP), J=5.901+-0.029(2M), H=5.632+-0.021(2M), Ks=5.579+-0.018(2M), V-Ks = 7.09 - 5.579 = 1.511. PASTEL: = 5812K(N=8), =4.485(N=8), <[Fe/H]>=0.00(N=8). Mixed signals on youth/activity: logR'HK=-4.96(Wright04), Prot=23.0d(Wright04), logR'HK= -4.930 ..-4.653(Pace13), vsini=10.0km/s(White07). GaiaDR2: plx=35.5142+-0.0571mas, no correction needed to G/Bp/Rp: G=6.9223+-0.0002, E(BR/RP)=Bp-Rp=0.8117, Bp-G=0.3486, G-Rp=0.4630. G-V = 6.9223 - 7.090 = -0.1677. HD 216008 = HIP 112730 G2/3V: Houk82 Among the 3 solar twins with parameters most similar to the Sun in Casali20. Casali20: Teff=5797+-9K, [Fe/H]=-0.030+-0.007, logg=4.409+-0.026, age=5.9+-1.11Gyr. Activity also similar to Sun: logR'HK=-4.90(Henry96). PASTEL: =5822K(N=3), logg=4.38(N=1,Sousa11), [Fe/H]=-0.04+-0.05(Sousa11). Teffs: 5750K(GaiaDR2#1), 5765K(Aguilera-Gomez18), 5773K(Sousa11,Adibekyan12,Carretta13,DelgadoMena14,Suarez-Andres17, Suarez-Andres18,CostaSilva20), 5797K(Casali20), 5819+-23K(Stevens17), 5822K(Netopil17), 5822K(GaiaDR2#2), 5822K(Casagrande11), 5848K(Stassun18), 5923K(Masana06) => adopt Casali20 (5797+-9K). V=8.21(HIP), V=8.21(TYC), V=8.215+-0.000(Hauck97), B-V=0.640+-0.001(HIP), B-V=0.660+-0.014(TYC), V-I=0.70+-0.00(HIP), J=7.058+-0.018(2M), H=6.809+-0.040(2M), Ks=6.674+-0.024(2M), V-Ks = 8.215 - 6.674 = 1.541. plx=19.45+-0.73mas(HIP2). GaiaDR2: plx=19.2503+-0.0505mas, G=8.0477+-0.0004, E(BR/RP)=1.188, Bp-Rp=0.8121, Bp-G=0.3456, G-Rp=0.4665. G-V = 8.0477 - 8.215 = -0.1673. ### Deprecated Standards or Variants HD 2141 = HIP 2014 = 2MASS J00253278-1608003 G2V: Keenan89,Keenan99(not in Keenan88) G3V: Houk88 G1V: McNeil86(by McNeil) *G2IV-V: McNeil86(by Keenan) Not particularly well-studied star that appears to be a subgiant rather than dwarf. The TIC(Stassun19) estimates logg=3.9492+-0.0789 and Rad=1.797+-0.089, so this star would appear to be somewhat evolved, as suggested in McNeil86. McNeil86 notes "metallic lines very slightly weak?". No published spectroscopic metallicities, at least in any Vizier-queryable tables. V=8.890(Mermilliod91), V=8.89(HIP), B-V=0.647+-0.010(HIP), B-V=0.630(Mermilliod91), U-B=0.160(Mermilliod91). plx = 8.57+-0.91 mas(van Leeuwen07), plx =8.5864+-0.0538(GaiaDR2), so the star may not necessarily have negligible reddening. Assuming negligible reddening Mv =3.56, so the star is ~1.3 mag above MS. Teffs: 5727+115-94K(Ammons06), 5819+-127.5K(Stassun19), 6079K(Bailer-Jones11). Both are photometric Teff estimates, no PASTEL spectroscopic parameters. HD 44594 = HR 2290 = HIP 30104 G2Va: Keenan89,Keenan99(not in Keenan88) *G1.5V: Gray06 G3V: Houk78 G4V: Jaschek78(Evans66) A "solar twin" from Cayrel de Strobel & Bentolila (1989). They state "In spite of a slight but significant difference in metal content, HD 44594 seems to be the most solar like dwarf found so far in the neighbourhood of the Sun and can be used as a solar-standard in precise spectrophotometric work." Further they "have found for this stars the same effective temperature (Teff = 5770+-40K), the same gravity, a very similar lithium abundance and similar chromospheric activity as for the Sun...", however the star is "slightly overabundant in heavy elements [M/H] = +0.15+-0.06)" and "all the metal lines are stronger in HD 44594 than in the Sun." Freil93 called HD 44594 "the Southern Hemisphere solar twin". I've only knocked this star down to tertiary standard since Gray06 recently classified 0.5 subtype earlier. B-V=0.660+-0.000(Mermilliod91), B-V=0.657+-0.006(HIP), V=6.605+-0.017(Mermilliod91), V=6.61(HIP), U-B=0.192+-0.146(Mermiliod91). Teffs: 5723+-110K(Bond06), 5741+-40K(Blackwell98), 5793K(Cayrel89), 5798K(diBenedetto98), 5840+-14K(Sousa08), 5844+-44K(Valenti05), 5855+-48K(Masana06), 5896K(Marsakov95) => median Teff = 5819K. Metallicities: [Fe/H]=0.04+-0.07(Bond06), 0.15+-0.01(Sousa08), 0.15+-0.03(Valenti05), so slightly metal-rich. HD 45184 = HR 2318 = GJ 3394 G0V: Boss37(G0),Oblak82(photometric) *G1.5V: Gray06 G2Va: Houk82(G2V),Keenan88,Keenan99 I've deprecated this standard since Gray06 recently classified 0.5 subtype earlier, and other authors have reported hotter types (note that Houk's G2V is more like ~G0.5V compared to other classifications using Keenan's standards). B-V = 0.626+-0.007 (HIP). The B-V color is slightly bluer than the Sun and Teffs slightly hotter. Teffs: 5790+-52K(Blackwell98), 5803K(diBenedetto98), 5810+-44K(Valenti05), 5820+-70K(Bensby03,Morel04,Feltzing07), 5828+-51K(Masana06), 5841K(Gray06), 5863+-63K(Casagrande11) 5869+-14K(Sousa08,DelgadoMena10,Adibekyan12), 5962K(Marsakov95) => median Teff = 5828K. PASTEL/Soubiran22 mean values: Teff=5859+-13K(N=18), logg=4.43+-0.03(N=14), [Fe/H]=+0.06+-0.02(N=14). HD 98230B = xi UMa B = HR 4374 G0V: Adams35,Keenan85 *G2V: Keenan88 From Tycho-2 photometry, I estimate (B-V) = 0.655+-0.014. Photometry not separated in Mermilliod91. 1" pair with xi UMa A, a F8.5V standard. Tight binary, so probably not the best choice of standard. HD 186408 = 16 Cyg A = HR 7503 = GJ 765.1A *G1.5Vb: Keenan83,Keenan88,Keenan89,GrayNstars G2V: JM53 Was one of 3 G2V standards in JohnsonMorgan53, then Keenan later considered it G1.5V. Teff = 5813+-18 K (Ramirez11). HD 10307 = HR 483 *G1V: Keenan89,Keenan99,Gray03,Barry70(G1Va) G2V: JM53,Jaschek64(all! N=24!),Jaschek78,Garcia89,Roman52 G1.5V: Garcia89(!),Hoffleit91 F8: Cannon18 Was one of 3 G2V standards in JohnsonMorgan53, then Keenan later considered it G1V. B-V(HIP) = 0.618+-0.001, B-V(HIP,G1V) = 0.602, Vmag(Merm91) = 4.958+-0.011. HD 141004 = lam Ser = HR 5868 = GJ 598 G0V : MK73 *G0V- : Keenan88,GrayNstars G2V: MK43 I would prefer not to consider a star a standard if Keenan changed the classifications 3 times. At least there is continuity on G0 type from MK73 to Keenan88 and to Gray, and G0 seems consistent with the B-V color. B-V = 0.604+-0.008 (HIP). HD 28099 = VB 64 = BD+16_601 = V911 Tau: G0V: Ramberg41,Jacoby84 *G2+V: Keenan85,Keenan89("H&K slightly weak") G4V: Adams35 G6V: Morgan65 G8V: Perraud62 One of two Hyads classified G6V by Morgan65. I should be surprised that Morgan called it G6V and Keenan calls it G2+V, but given the ridiculous inconsistencies that appear in the MK classifications, I am not. The range of types appears to be too large to attribute to the star's variability. For some reason Jacoby84 calls this star a G0V with E(B-V)=0.03, despite it being a member of the Hyades (negligible reddening; did they adopt the Ramberg41 type?). And even more inexplicably, Navarro12 adopts the Jacoby84 type for their automated spectral classification work. Plenty of published Teffs in Soubiran10 catalog, median Teff = 5793K (so likely ~G2V). The star is a tight binary (0.4"), with mag(A)=6.60, mag(B)=11.47 in the WDS. Rotation period 8.67 days. Could the range in types be due to variability/spottedness? Given the wide range of published types, this star should probably not be be considered a standard. ### Exemplars Note that these are stars with good agreement in the literature on G2V types, but they are not necessarily 'solar twins', i.e. their gravity, [Fe/H] may differ a bit from solar but their low/medium resolution spectra match the Sun and other G2V standards better than those of other types. alf Cen A = GJ 559 A = HIP 71683 = HD 128620 = HR 5459 G0: HD G1: Luyten79(LHS) *G2V: Woods55,Garrison96,Houk75(Garrison),Ayres76,Kamper78,Garrison96,Gray06 G4V: Adams35 There are surprisingly few published classifications for Alf Cen A. Good agreement on G2V. Garrison96 lists alf Cen A as the only other very bright star besides the Sun (among the brightest ~300 stars with V<3.55mag) to be classified G2V. The star is negligble hotter but more metal-rich than the Sun. PASTEL compilation (queried 5/18/2017) has mean Teff = 5786+-14 K(N=22), [Fe/H] = 0.22+-0.01(N=18), logg=4.32+-0.01(N=18). Recent values with small uncertainties are provided by Heiter15: Teff=5792+-16K, logg=4.31+-0.01. So this is basically a metal-rich solar "twin", with solar Teff (within uncertainties), and slightly lower surface gravity. Bessell83 (http://articles.adsabs.harvard.edu/full/1983PASP...95..480B) quotes V(A) = 0.003, B-V(A)=0.633, V-R(A)=0.362, R-I(A)=0.331, V-I(A)=0.639. There is suprisingly some debate on the parallax for the alf Cen system at the ~few mas level: Pourbaix16: 743+-1.3mas(Pourbaix16). Angular diameter: tet_LD(A)=8.502+-0.038mas(0.43% unc.; Kervella17). For plx=747.17+-0.61mas, Kervella19 derives R_A=1.2234+-0.0053 Rsun, but with Pourbaix16 plx I get slightly larger: 1.2303Rsun. fbol(A)=(27.16+-0.27)e-9 W/m2 (Boyajian13) => mbol=-0.082+-0.011(IAU2015) => BCv = mbol - V = (-0.082+-0.011)-(0.003) = -0.085. HD 217014 = HR 8729 = 51 Peg G0: Cannon *G2V: Bidelman85,Gray01,Gray06(G2V+),1957ArA.....2...55O G2IV: Keenan89(stan) G2.5IVa: Keenan80 G3V: Gray03 G4V: Stebbins57 G5V: Cowley79,Jaschek78(Harlan70) Famous planet host, whose evolutionary status I recalled discussed in an IAU circular after the planet was found in 1995. Basically a metal-rich G2V star with nearly identical Teff to Sun, and spectroscopic logg consistent with dwarf. V=5.456+-0.004(Hauck97), V=5.45(HIP), V=5.467+-0.020(Mermilliod91), B-V=0.665+-0.012(Mermilliod91), B-V=0.666+-0.007(HIP), U-B=0.233+-0.028(Mermilliod91), V-Ic=0.69+-0.01(HIP). Revised HIP data => Mv=4.48, so 0.41 mag above MS. Temperature types are in G0-G5 range. Clearly a dwarf, only considered subgiant by Keenan89. PASTEL median values: = 5773K (N=33), <[Fe/H]>=+0.19(N=33), =4.33(N=37), i.e.. 2MASS JH poor but good flag=A for Ks: Ks=3.911+-0.021(2MASS,q=A). # Other Stars Morgan65 did not classify any Hyads as G2V. HR 4523 = HD 102365 = HIP 57443 = GJ 442A = LHS 311 G2V: Gray06 G2.5III: Keenan00 *G3V: Keenan89(non-stan) G3/5V: Houk82 G4V: Adams35 G5V: Evans57 G6: Bidelman85 Remarkably poor agreement on spectral type, perhaps due to being somewhat metal poor ([Fe/H] ~ -0.3). Gray06 classifies it as G2V, but it appears to be ~150K cooler than Sun. Strangely, Keenan89 lists it as non-standard star of G3V, but then the 'final' version of Keenan's table posted after his passing (http://www.astronomy.ohio-state.edu/MKCool/mkcat.html) lists it as "G2.5III" (which it had to be obvious that this high pm star at 9pc was not a giant?). Reported to have an exoplanet HD102365b (Tinney11). Has M4V companion 23" away (Henry02). V=4.890+-0.011(Mermilliod91), B-V=0.665+-0.005(Mermilliod91), U-B=0.100+-0.000(Mermilliod91). plx = 107.6210+-0.1636 mas(GaiaDR2) => Mv = 5.049+-0.011 mag, so clearly on the main sequence and not a giant as classified by Keenan89. The color and absolute magnitude suggest that the star is just a tad cooler and dimmer than the Sun. PASTEL published values: = 5623K(N=18), <[Fe/H]> = -0.29(N=13), = 4.46(N=13). HR 7569 = HD 187923 G0V: Harlan69 *G2V: Roman55 G3: Bidelman85 Only listed it as it was one of the coolest evolved stars (logg<4.1) in CATSUP, after the thin disk star 70 Vir and thick disk star HR 173(HD 3795). Still assessing whether this is very old thin disk or thick disk, but I think from the combination of kinematics and abundances that it is likely to be a "hamr" star (Adebakian13) or 'intermediate disc' star (Fuhrmann17)? PASTEL: = 5706K(N=14), =4.05(N=8), <[Fe/H]>=-0.125(N=10). Isaacson10: logR'HK=-5.0150, 1.08 mag above MS, Age: 8.1(6.8-10.1)Gyr(Valenit05), 9.60(9.04-10.20)Gyr(Takeda07), 8.8(8.2-9.5)Gyr(Brewer16), 10.20(6.19-10.95)Gyr(Casagrande11), 10.30(6.77-11.09)Gyr(Casagrande11#2), 8.52Gyr(Luck17/Bertelli94), 9.00Gyr(Luck17#2/Dotter08), 11.38Gyr(Luck17#3/BASTI), 9.63Gyr(Luck17/average), 10.9(10.0-11.8)Gyr(Holmberg09). [Mg/Fe]=0.216(Borkova05,Cenarro09), [a/Fe]=0.14(Casagrande11), [a/Fe]=0.22(Lee11), [a/Fe]=0.121,0.131(Lee11#2). Using xHIP UVW, and Bensby14, I estimate P(thin)=90.8%, P(thick)=8.9%, P(halo)=3e-3%, P(Hercules)=0.32%. HD 9986 *G2V: Gray03 G5V: Harlan70 Gray03 considered the star a 'solar twin'. HD 145825 G1V: Houk82 *G2V: Gray06 G3V: Torres06 HD 195564 = HR 7845 *G2V: Abt85,Gray03 G2.5IV: Keenan80,Keenan89 G3V: Adams35 HD 196141 *G2V: Gray06,Torres06 G3V: Houk78 HD 20619 G1.5V: Keenan89 G2V: Wilson50,Gray03 HD 38858 *G2V: Gray03,Harlan81 G4V: Wilson50 G4IV-V: 1966ZfA....64..269A HD 88084 *G2V: Schild71,Gray06