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Sirius
Sirius is the brightest star in the night sky. Its name is derived from the Greek word Σείριος (Latin script: Seirios; lit. 'glowing' or 'scorching'). The star is designated α Canis Majoris, Latinized to Alpha Canis Majoris, and abbreviated α CMa or Alpha CMa. With a visual apparent magnitude of −1.46, Sirius is almost twice as bright as Canopus, the next brightest star. 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. The distance between the two varies between 8.2 and 31.5 astronomical units as they orbit every 50 years.
Sirius appears bright because of its intrinsic luminosity and its proximity to the Solar System. At a distance of 2.64 parsecs (8.6 ly), the Sirius system is one of Earth's nearest neighbours. Sirius is gradually moving closer to the Solar System and it is expected to increase in brightness slightly over the next 60,000 years to reach a peak magnitude of −1.68. Coincidentally, at about the same time, Sirius will take its turn as the southern Pole Star, around the year 66,270 AD. In that year, Sirius will come to within 1.6 degrees of the south celestial pole. This is due to axial precession and proper motion of Sirius itself which moves slowly in the SSW direction, so it will be visible from the southern hemisphere only. After 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.
Sirius A is about twice as massive as the Sun (M☉) and has an absolute visual magnitude of +1.43. 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. The system is between 200 and 300 million years old. It was originally composed of two bright bluish stars. 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.
Sirius is colloquially known as the "Dog Star", reflecting its prominence in its constellation, Canis Major (the Greater Dog). 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.
The proper name "Sirius" comes from the Latin Sīrius, from the Ancient Greek Σείριος (Seirios, "glowing" or "scorcher"). The Greek word itself may have been imported from elsewhere before the Archaic period, one authority suggesting a link with the Egyptian god Osiris. The name's earliest recorded use dates from the 7th century BC in Hesiod's poetic work Works and Days. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included Sirius for the star α Canis Majoris A. It is now so entered in the IAU Catalog of Star Names.
Sirius has over 50 other designations and names attached to it. In Geoffrey Chaucer's essay Treatise on the Astrolabe, it bears the name Alhabor and is depicted by a hound's head. This name is widely used on medieval astrolabes from Western Europe. In Sanskrit it is known as Mrgavyadha "deer hunter", or Lubdhaka "hunter". As Mrgavyadha, the star represents Rudra (Shiva). The star is referred to as Makarajyoti in Malayalam and has religious significance to the pilgrim center Sabarimala. In Scandinavia, the star has been known as Lokabrenna ("burning done by Loki", or "Loki's torch"). In the astrology of the Middle Ages, Sirius was a Behenian fixed star, associated with beryl and juniper. Its astrological symbol 
was listed by Heinrich Cornelius Agrippa.
As the brightest star in the night sky, Sirius appears in some of the earliest astronomical records. 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. This rising occurs at Cairo on 19 July (Julian), placing it just before the onset of the annual flooding of the Nile during antiquity. 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"; Ancient Greek: Σῶθις}, Sō̂this), guarantor of the fertility of their land (see Sothic cycle). As Sirius is visible together with the constellation of Orion, the Egyptians worshiped Orion as the god Sah, the husband of Sopdet, with whom she had a son, the sky god Sopdu. The goddess Sopdet was later syncretized with the goddess Isis, Sah was linked with Osiris (which is by some suggested as a root for the name of Sirius), and Sopdu was linked with Horus. The joining of Sopdet with Isis would allow Plutarch to state that "The soul of Isis is called Dog by the Greeks", meaning Sirius worshiped as Isis-Sopdet by Egyptians was named the Dog by the Greeks and Romans. The 70 day period of the absence of Sirius from the sky was understood as the passing of Sopdet-Isis and Sah-Osiris through the Egyptian underworld.
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 its brightness, Sirius would have been seen to twinkle more in the unsettled weather conditions of early summer. To Greek observers, this signified emanations that caused its malignant influence. Anyone suffering its effects was said to be "star-struck" (ἀστροβόλητος, astrobólētos). It was described as "burning" or "flaming" in literature. The season following the star's reappearance came to be known as the "dog days". 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. If it rose clear, it would portend good fortune; if it was misty or faint then it foretold (or emanated) pestilence. Coins retrieved from the island from the 3rd century BC feature dogs or stars with emanating rays, highlighting Sirius's importance.
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Sirius
Sirius is the brightest star in the night sky. Its name is derived from the Greek word Σείριος (Latin script: Seirios; lit. 'glowing' or 'scorching'). The star is designated α Canis Majoris, Latinized to Alpha Canis Majoris, and abbreviated α CMa or Alpha CMa. With a visual apparent magnitude of −1.46, Sirius is almost twice as bright as Canopus, the next brightest star. 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. The distance between the two varies between 8.2 and 31.5 astronomical units as they orbit every 50 years.
Sirius appears bright because of its intrinsic luminosity and its proximity to the Solar System. At a distance of 2.64 parsecs (8.6 ly), the Sirius system is one of Earth's nearest neighbours. Sirius is gradually moving closer to the Solar System and it is expected to increase in brightness slightly over the next 60,000 years to reach a peak magnitude of −1.68. Coincidentally, at about the same time, Sirius will take its turn as the southern Pole Star, around the year 66,270 AD. In that year, Sirius will come to within 1.6 degrees of the south celestial pole. This is due to axial precession and proper motion of Sirius itself which moves slowly in the SSW direction, so it will be visible from the southern hemisphere only. After 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.
Sirius A is about twice as massive as the Sun (M☉) and has an absolute visual magnitude of +1.43. 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. The system is between 200 and 300 million years old. It was originally composed of two bright bluish stars. 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.
Sirius is colloquially known as the "Dog Star", reflecting its prominence in its constellation, Canis Major (the Greater Dog). 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.
The proper name "Sirius" comes from the Latin Sīrius, from the Ancient Greek Σείριος (Seirios, "glowing" or "scorcher"). The Greek word itself may have been imported from elsewhere before the Archaic period, one authority suggesting a link with the Egyptian god Osiris. The name's earliest recorded use dates from the 7th century BC in Hesiod's poetic work Works and Days. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included Sirius for the star α Canis Majoris A. It is now so entered in the IAU Catalog of Star Names.
Sirius has over 50 other designations and names attached to it. In Geoffrey Chaucer's essay Treatise on the Astrolabe, it bears the name Alhabor and is depicted by a hound's head. This name is widely used on medieval astrolabes from Western Europe. In Sanskrit it is known as Mrgavyadha "deer hunter", or Lubdhaka "hunter". As Mrgavyadha, the star represents Rudra (Shiva). The star is referred to as Makarajyoti in Malayalam and has religious significance to the pilgrim center Sabarimala. In Scandinavia, the star has been known as Lokabrenna ("burning done by Loki", or "Loki's torch"). In the astrology of the Middle Ages, Sirius was a Behenian fixed star, associated with beryl and juniper. Its astrological symbol was listed by Heinrich Cornelius Agrippa.
As the brightest star in the night sky, Sirius appears in some of the earliest astronomical records. 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. This rising occurs at Cairo on 19 July (Julian), placing it just before the onset of the annual flooding of the Nile during antiquity. 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"; Ancient Greek: Σῶθις}, Sō̂this), guarantor of the fertility of their land (see Sothic cycle). As Sirius is visible together with the constellation of Orion, the Egyptians worshiped Orion as the god Sah, the husband of Sopdet, with whom she had a son, the sky god Sopdu. The goddess Sopdet was later syncretized with the goddess Isis, Sah was linked with Osiris (which is by some suggested as a root for the name of Sirius), and Sopdu was linked with Horus. The joining of Sopdet with Isis would allow Plutarch to state that "The soul of Isis is called Dog by the Greeks", meaning Sirius worshiped as Isis-Sopdet by Egyptians was named the Dog by the Greeks and Romans. The 70 day period of the absence of Sirius from the sky was understood as the passing of Sopdet-Isis and Sah-Osiris through the Egyptian underworld.
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 its brightness, Sirius would have been seen to twinkle more in the unsettled weather conditions of early summer. To Greek observers, this signified emanations that caused its malignant influence. Anyone suffering its effects was said to be "star-struck" (ἀστροβόλητος, astrobólētos). It was described as "burning" or "flaming" in literature. The season following the star's reappearance came to be known as the "dog days". 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. If it rose clear, it would portend good fortune; if it was misty or faint then it foretold (or emanated) pestilence. Coins retrieved from the island from the 3rd century BC feature dogs or stars with emanating rays, highlighting Sirius's importance.
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