Sirius astrological symbol was listed by Heinrich Cornelius Agrippa. Many cultures have historically attached special significance to Sirius, particularly in relation to dogs. It is often colloquially called the "Dog Star" as the brightest star of Canis Major, the "Great Dog" constellation. It was classically depicted as Orion's dog. The Ancient Greeks thought that Sirius's emanations could affect dogs adversely, making them behave abnormally during the "dog days," the hottest days of the summer. The Romans knew these days as "dies caniculares", and the star Sirius was called Canicula, "little dog." The excessive panting of dogs in hot weather was thought
The Sirius Mystery Culture". One unproven aspect of the reported Dogon knowledge of the Sirius system is the assertion that the Dogon knew of another star in the Sirius system, Emme Ya, or "larger than Sirius B but lighter and dim in magnitude." A dynamical study published in 1995, based on anomalous perturbations of Sirius B (suggestive of the star being gravitationally influenced by another body) concluded that the presence of a third star orbiting Sirius could not be ruled out. An apparent "third star" observed in the 1920s is now confirmed as a background object, something previously suggested by Holberg in 2007: