A large bibliography of these results is contained in Cayrel de Strobel (1996), but we would welcome e-mails warning us about any results we may have overlooked. In these searches for solar analogs, a recurring issue is the determination of the B-V index of the Sun. The most widely used effective temperature parameter in galactic and extragalactic research is the color index B-V and the most well-studied star is the Sun. But the B-V value of the Sun is still controversial. The large scatter between various determinations is visualized in Figure 1 from Gray (1992) which we find reproduced in the materials for this meeting. Gray's figure shows that, starting with the publication by Gallouet (1964), the B-V value of the Sun determined by various authors has ranged from 0.60 to 0.68. The color indices of the Sun in photometric systems other than UBV are not better known either.
The problem of finding actual solar twins, rather than the broader category of solar analogs, was raised by Hardorp in a series of 8 papers (1978-1983). Whether or not the spectral type of the Sun matches the spectral type of stars to which one attributed a G2V spectral type, other stars all have weaker UV absorption than the Sun when photoelectrically scanned in the wavelength interval 3650-4060 Å.