![]() ![]() ![]() If it rose clear, it would portend good fortune if it was misty or faint then it foretold (or emanated) pestilence. The inhabitants of the island of Ceos in the Aegean Sea would offer sacrifices to Sirius and Zeus to bring cooling breezes and would await the reappearance of the star in summer. The season following the star's reappearance came to be known as the "dog days". It was described as "burning" or "flaming" in literature. ![]() ![]() Anyone suffering its effects was said to be "star-struck" ( ἀστροβόλητος, astrobólētos). To Greek observers, this signified emanations that caused its malignant influence. Owing to its brightness, Sirius would have been seen to twinkle more in the unsettled weather conditions of early summer. The ancient Greeks observed that the appearance of Sirius as the morning star heralded the hot and dry summer and feared that the star caused plants to wilt, men to weaken, and women to become aroused. Owing to the flood's own irregularity, the extreme precision of the star's return made it important to the ancient Egyptians, who worshipped it as the goddess Sopdet ( Ancient Egyptian: Spdt, "Triangle" Greek: Σῶθις}, Sō̂this), guarantor of the fertility of their land. This rising occurs at Cairo on 19 July ( Julian), placing it just before the onset of the annual flooding of the Nile during antiquity. Its displacement from the ecliptic causes its heliacal rising to be remarkably regular compared to other stars, with a period of almost exactly 365.25 days holding it constant relative to the solar year. The brightest star seen from Earth, Sirius is recorded in some of the earliest astronomical records. The heliacal rising of Sirius marked the flooding of the Nile in Ancient Egypt and the " dog days" of summer for the ancient Greeks, while to the Polynesians, mostly in the Southern Hemisphere, the star marked winter and was an important reference for their navigation around the Pacific Ocean. Sirius is colloquially known as the " Dog Star", reflecting its prominence in its constellation, Canis Major (the Greater Dog). The initially more massive of these, Sirius B, consumed its hydrogen fuel and became a red giant before shedding its outer layers and collapsing into its current state as a white dwarf around 120 million years ago. It was originally composed of two bright bluish stars. The system is between 200 and 300 million years old. It is 25 times as luminous as the Sun, but has a significantly lower luminosity than other bright stars such as Canopus, Betelgeuse, or Rigel. Sirius A is about twice as massive as the Sun ( M ☉) and has an absolute visual magnitude of +1.43. So it will be visible from the southern hemisphere only.Īfter that time, its distance will begin to increase, and it will become fainter, but it will continue to be the brightest star in the Earth's night sky for approximately the next 210,000 years, at which point Vega, another A-type star that is intrinsically more luminous than Sirius, becomes the brightest star. This is due to precession and proper motion of Sirius itself which moves slowly in the SSW direction. In that year, Sirius will come to within 1.6 degrees of the south celestial pole. Sirius is gradually moving closer to the Solar System it is expected to increase in brightness slightly over the next 60,000 years to reach a peak magnitude of −1.68.Ĭoincidentally, at about the same time, Sirius will take its turn as the southern Pole Star, around the year 66270. At a distance of 2.64 parsecs (8.6 ly), the Sirius system is one of Earth's nearest neighbours. Sirius appears bright because of its intrinsic luminosity and its proximity to the Solar System. The distance between the two varies between 8.2 and 31.5 astronomical units as they orbit every 50 years. Sirius is a binary star consisting of a main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion of spectral type DA2, termed Sirius B. With a visual apparent magnitude of −1.46, Sirius is almost twice as bright as Canopus, the next brightest star. The star is designated α Canis Majoris, Latinized to Alpha Canis Majoris, and abbreviated α CMa or Alpha CMa. Its name is derived from the Greek word Σείριος, or Seirios, meaning lit. Sirius is the brightest star in the night sky. Dog Star, Aschere, Canicula, Al Shira, Sothis, Alhabor, ![]()
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