No. 43: Jan-Feb 1986
Many Greek, Roman, and Babylonian sources definitely label Sirius as being a red star. Some dispute these old accounts because today Sirius is white with a bluish tinge, and is classified as a white dwarf. W. Schlosser and W. Bergmann have now found a "new," and apparently independent reference to Sirius' red color. It is in a manuscript of Lombardic origin, which contains the otherwise lost "De Cursu Stellarum" by Gregory of Tours (who lived about 538593 AD). This new source reiterates that Sirius was once a red star, leading Schlosser and Bergmann to speculate as follows:
"Thus, Sirius B might well have changed from a red giant to the white dwarf as it appears today. However, the rapidity and smoothness of this transformation are quite unexpected, and its timescale is surprisingly short. Furthermore, no traces of catastrophic effects connected with such an event have ever been found. The only indication that something has happened is the somewhat higher metallicity of Sirius A, believed to have resulted from contamination by the giant's blown-off shell."
(Schlosser, Wolfhard, and Bergmann, Werner; "An Early-Medieval Account on the Red Color of Sirius and Its Astrophysical Implications," Nature, 318:45, 1985.)
References. See BHT5 in our catalog: Biological Anomalies: Humans I for the surmise that the ancients, especially those of the heroic age, were color-blind! In this issue's PSYCHOLOGY section, we find that the ancients may have been deficient in another, even stranger way. The above-mentioned catalog is described here.