The angular diameters, radii, and effective temperatures of 16 G0-G5 main-s
equence stars with color excesses 0.60 less than or equal to B-V less than
or equal to 0.68 and parallaxes derived from Hipparcos data have been deter
mined using their infrared fluxes, obtained from JHKLM photometric observat
ions. For all the stars except BS 483, these effective temperatures differ
from the spectroscopic temperatures by no more than 1-2%. Such differences
are within the uncertainties expected for the IR-Aux method. The effective
temperatures of BS 483 derived from its infrared fluxes are 3% higher than
those indicated by spectroscopic observations; this may be due to the speci
fic atmospheric structure of this star. Spectroscopic observations at 3400-
7500 Angstrom and JHKLM photometric observations are compared with analogou
s solar data and Kurucz models. The best agreement with the model with T-ef
f = 5750 K and logg = 4.5 in the interval 4400-7500 Angstrom was obtained f
or BS 7503 and BS 7504 (16 Cyg A and 16 Cyg B). The infrared color indices
H - K, K - L, and K - M for these stars differ from the corresponding solar
indices, and their angular diameters grow with wavelength, which is not th
e case for the Sun. H - K for BS 6060, currently considered to be the close
st analog to the Sun, is near the solar value. The vast majority of the sta
rs studied (13 of 16) have higher luminosities than the Sun. These include
16 Cyg A, 16 Cyg B, and 51 Peg, which thus cannot be considered full "twins
" of the Sun. (C) 2000 MAIK "Nauka/Interperiodica".