 The visible star is now sometimes known as Sirius A. Since 1894, some apparent orbital irregularities in the Sirius system have been observed, suggesting a third very small companion star, but this has never been definitely confirmed. The best fit to the data indicates a six-year orbit around Sirius A and a mass of only 0.06 M ☉. This star would be five to ten magnitudes fainter than the white dwarf Sirius B, which would account for the difficulty of observing it. Observations published in 2008 were unable to detect either a third star or a planet. An apparent "third star" observed in the 1920s is now confirmed as a background object.
