Sirius is the brightest star in the night sky. With a visual apparent magnitude of -1.46, it is almost twice as bright as Canopus, the next brightest star. The name „Sirius” is derived from the Ancient Greek Seirios („glowing” or „scorcher”). The star has the Bayer designation Alpha Canis Majoris. What the naked eye perceives as a single star is actually a binary star system, consisting of a white main sequence star of spectral type A1V, termed Sirius A, and a faint white dwarf companion of spectral type DA2, termed Sirius B. The distance separating Sirius A from its companion varies between 8.1 and 31.5 AU.
Sirius appears bright because of both its intrinsic luminosity and its proximity to Earth. At a distance of 2.6 parsecs (the Sirius system is one of Earth’s near neighbors. Sirius A is about twice as massive as the Sun and has an absolute visual magnitude of 1.42. It is 25 times more luminous than the Sun but has a significantly lower luminosity than other bright stars such as Canopus or Rigel.
The system is between 200 and 300 million years old. It was originally composed of two bright bluish stars. The more massive of these, Sirius B, consumed its resources 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 can be seen from almost every inhabited region of the Earth’s surface (those living north of 73.284 degrees cannot see it) and, in the Northern Hemisphere, is known as a vertex of the Winter Triangle. The best time of year to view it is around January 1, when it reaches the meridian at midnight. Under the right conditions, Sirius can be observed in daylight with the naked eye. Ideally the sky must be very clear, with the observer at a high altitude, the star passing overhead, and the sun low down on the horizon.
Sirius is also known colloquially as the „Dog Star”, reflecting its prominence in its constellation, Canis Major (Big 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 it marked winter.
BINARY STARS. A Binary Star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary. Research between the early 19th century and today suggests that many stars are part of either binary star systems or star systems with more than two stars, called multiple star systems. The term double star may be used synonymously with binary star, but more generally, a double star may be either a binary star or an optical double star which consists of two stars with no physical connection but which appear close together in the sky as seen from the Earth.
A double star may be determined to be optical if its components have sufficiently different proper motions or radial velocities, or if parallax measurements reveal its two components to be at sufficiently different distances from the Earth. Most known double stars have not yet been determined to be either bound binary star systems or optical doubles.
If components in binary star systems are close enough they can gravitationally distort their mutual outer stellar atmospheres. In some cases, these close binary systems can exchange mass, which may bring their evolution to stages that single stars cannot attain. Examples of binaries are Algol (an eclipsing binary), Sirius, and Cygnus X-1 (of which one member is probably a black hole). Binary stars are also common as the nuclei of many planetary nebulae, and are the progenitors of both novae and type Ia supernovae.
SIRIUS STAR SYSTEM. What appears as a single star is actually a large binary star system, consisting of a bright white main sequence star of spectral type A1V, named Sirius A, and a faint white dwarf companion of spectral type DA named Sirius B. Sirius B is invisible to the naked eye but packs almost the entire mass of our sun into a globe only 4 times as large as the Earth. Sirius B’s surface is 300 times harder than diamonds, while its interior has a density 3,000 times that of diamonds. Spinning on its axis about 23 times a minute, it generates huge magnetic fields around it.
The two stars, Sirius A and Sirius B move around each other, constantly exchanging particles. Because of its greater density and magnetic field, Sirius B takes the lion’s share, taking gases and materials off of its larger host body. Sirius B has a super-heavy gravitationally powerful star made of concentrated super-dense matter (essence) with the number 50 associated with it (describing its orbital period). Every 49.9 years, Sirius A and B, come as close together as their orbits allow, creating huge magnetic storms between them. As they approach each other, the stars both begin to spin faster as tidal forces become stronger, finally flip-flopping over, actually trading places with each other. This energy is eventually released to flow on magnetic field lines to the Sun, which transmits it like a lens to all the planets.
When a star like our sun gets to be very old, after another seven billion years or so, it will no longer be able to sustain burning its nuclear fuel. With only about half of the its mass remaining, it will shrink to a fraction of its radius and become a white dwarf star. White dwarfs are common, the most famous one being the companion to the brightest star in the sky, Sirius. Although they are common and represent the final stage of our own sun, astronomers still do not understand their full range of character, or the parameters that determine what they ultimately become. One reason is that many white dwarfs are, like the companion of Sirius, located in binary systems in which the companion stars influence the details of how they age.
TRUE COLOR. Around 150 AD, the Hellenistic astronomer Claudius Ptolemy described Sirius as reddish, along with five other stars, Betelgeuse, Antares, Aldebaran, Arcturus and Pollux, all of which are clearly of orange or red hue. The discrepancy was first noted by amateur astronomer Thomas Barker, squire of Lyndon Hall in Rutland, who prepared a paper and spoke at a meeting of the Royal Society in London in 1760. The existence of other stars changing in brightness gave credence to the idea that some may change in color too; Sir John Herschel noted this in 1839, possibly influenced by witnessing Eta Carinae two years earlier. Thomas Jefferson Jackson He cited not only Ptolemy but also the poet Aratus, the orator Cicero, and general Germanicus as coloring the star red, though acknowledging that none of the latter three authors were astronomers, the last two merely translating Aratus’ poem Phaenomena. Seneca, too, had described Sirius as being of a deeper red color than Mars. However, not all ancient observers saw Sirius as red.
The 1st century AD poet Marcus Manilius described it as „sea-blue”, as did the 4th century Avienus. It is the standard star for the color white in ancient China, and multiple records from the 2nd century BC up to the 7th century AD all describe Sirius as white in hue. In 1985, German astronomers Wolfhard Schlosser and Werner Bergmann published an account of an 8th century Lombardic manuscript, which contains De cursu stellarum ratio by St. Gregory of Tours. The Latin text taught readers how to determine the times of nighttime prayers from positions of the stars, and Sirius is described within as rubeola – „reddish”. The authors proposed this was further evidence Sirius B had been a red giant at the time. However, other scholars replied that it was likely St. Gregory had been referring to Arcturus instead.
The possibility that stellar evolution of either Sirius A or Sirius B could be responsible for this discrepancy has been rejected by astronomers on the grounds that the timescale of thousands of years is too short and that there is no sign of the nebulosity in the system that would be expected had such a change taken place. An interaction with a third star, to date undiscovered, has also been proposed as a possibility for a red appearance. Alternative explanations are either that the description as red is a poetic metaphor for ill fortune, or that the dramatic scintillations of the star when it was observed rising left the viewer with the impression that it was red. To the naked eye, it often appears to be flashing with red, white and blue hues when near the horizon.
Some ancient observations of Sirius describe it as a red star. To the Romans this meant an angry god, and they are known to have sacrificed red dogs to this star. Today, Sirius A is bluish white. The possibility that stellar evolution of either Sirius A or Sirius B could be responsible for this discrepancy is rejected by astronomers on the grounds that the timescale of thousands of years is too short and that there is no sign of the nebulosity in the system that would be expected had such a change taken place. Alternative explanations are either that the description as red is a poetic metaphor for ill fortune, or that the dramatic scintillations of the star when it was observed rising left the viewer with the impression that it was red. To the naked eye, it often appears to be flashing with red/white/blue hues when near the horizon. Sirius is the standard star for the color white in ancient China. Multiple records from the 2nd century BC up to the 7th century AD all describe Sirius as white in hue.
HISTORY & MYTHOLOGY. Historically, many cultures have attached special significance to Sirius.
EGYPT. Sirius, known in ancient Egypt as Sopdet or Sothis, is recorded in the earliest astronomical records. The hieroglyph for Sothis features a star and a triangle. During the era of the Middle Kingdom, Egyptians based their calendar on the heliacal rising of Sirius, namely the day it becomes visible just before sunrise after moving far enough away from the glare of the Sun. This occurred just before the annual flooding of the Nile and the summer solstice, after a 70-day absence from the skies.
Sothis was identified with (the embodiment of) Isis, wife and consort of Osiris who appeared in the sky as Orion. Together they formed a trinity with their son Horus. The 70-day period symbolized the passing of Isis and Osiris through the duat (Egyptian underworld). Sothis (isis) and her husband, the god named Sah (Orion), came to be viewed as manifestations of Isis and Osiris.
She was not only represented as a woman with a star on top of her headdress, but as a seated cow with a plant between her horns (just as Seshat‘s hieroglyph might have been a flower or a star) as depicted on an ivory tablet of King Djer. The plant may have been symbolic of the year, and thus linking her to the yearly rising of Sirius and the New Year. She was very occasionally depicted as a large dog, or in Roman times, as the goddess Isis-Sopdet, she was shown riding side-saddle on a large dog.
The New Year. Sirius was both the most important star of ancient Egyptian astronomy, and one of the Decans (star groups into which the night sky was divided, with each group appearing for ten days annually). The heliacal rising (the first night that Sirius is seen, just before dawn) was noticed every year during July. Early Egyptians used this to mark the start of the New Year (‘The Opening of the Year’). It was celebrated with a festival known as ‘The Coming of Sopdet’. As early as the 1st Dynasty, Sophis was known as ‘the bringer of the new year and the Nile flood’. When Sirius appeared in the sky each year, the Nile generally started to flood and bring fertility to the land.
The ancient Egyptians connected the two events, and so Sopdet took on the aspects of a goddess of not only the star and of the inundation, but of the fertility that came to the land of Egypt with the flood. The flood and the rising of Sirius also marked the ancient Egyptian New Year, and so she also was thought of as a goddess of the New Year.
Her aspect of being a fertility goddess was not just linked to the Nile. By the Middle Kingdom, she was believed to be a mother goddess, and a nurse goddess, changing her from a goddess of agriculture to a goddess of motherhood. This probably was due to her strong connection with the mother-goddess Isis. Not just a goddess of the waters of the inundation, Sopdet had another link with water – she was believed to cleanse the pharaoh in the afterlife. It is interesting to note that the embalming of the dead took seventy days – the same amount of time that Sirius was not seen in the sky, before it’s yearly rising. She was a goddess of fertility to both the living and the dead. In the Pyramid Texts, she is the goddess who prepares yearly sustenance for the pharaoh, ‘in this her name of „Year”‘.
She is also thought to be a guide in the afterlife for the pharaoh, letting him fly into the sky to join the gods, showing him ‘goodly roads’ in the Field of Reeds and helping him become one of the imperishable stars. She was thought to be living on the horizon, encircled by the Duat. Paralleling the story of Osiris and Isis, the pharaoh was believed to have had a child with Sopdet.
AFRICA – DOGON. The Dogon describe this ‘star’ specifically as having a circle of reddish rays around it, and this circle of rays is ‘like a spot spreading’ but remaining the same size. The Dogon are a West African tribe who have known about, and worshipped, Sirius A and its twin the invisible star Sirius B, for the past 5,000 years. They are have also been aware of the planets circle the sun in elliptical orbits, the four moons of Jupiter and the rings of Saturn.
They say that Sirius B is immensely heavy, invisible, very small, yet extremely powerful. Their understanding of the two stars’ orbits coincides exactly with modern astronomical findings, yet was arrived at thousands of years before it was scientifically proven. They also claim that a third star Emme Ya – Sorghum Female – exists in the Sirius system. Larger and lighter than Sirius B, this star revolves around Sirius A as well.
The Dogon also believe that approximately 5,000 years ago, Amphibious Gods, called Nommo, came to Earth in three legged space ships from the Sirius Star System. They have described perfectly the DNA pattern made by this elliptical orbit created by the two stars as they rotate make around each other. They believe Sirius to be the axis of the universe, and from it all matter and all souls are produced in a great spiral motion.
GREECE. The ancient Greeks observed that the appearance of Sirius heralded the hot and dry summer, and feared that it caused plants to wilt, men to weaken, and women to become aroused. Due to its brightness, Sirius would have been noted to twinkle more in the unsettled weather conditions of early summer. To Greek observers, this signified certain emanations which caused its malignant influence. People suffering its effects were said to be astroboletosor „star-struck”. It was described as „burning” or „flaming” in literature. The season following the star’s appearance came to be known as the Dog Days of summer.
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’ importance. The Romans celebrated the heliacal setting of Sirius around April 25, sacrificing a dog, along with incense, wine, and a sheep, to the goddess Robigo so that the star’s emanations would not cause wheat rust on wheat crops that year. Ptolemy of Alexandria mapped the stars in Books VII and VIII of his Almagest, in which he used Sirius as the location for the globe’s central meridian. He curiously depicted it as one of six red-colored stars. The other five are class M and K stars, such as Arcturus and Betelgeuse.
CHINA. In Chinese astronomy the star is known as the star of the „celestial wolf”. Several cultures also associated the star with a bow and arrows. The Ancient Chinese visualized a large bow and arrow across the southern sky, formed by the constellations of Puppis and Canis Major. In this, the arrow tip is pointed at the wolf Sirius. A similar association is depicted at the Temple of Hathor in Dendera, where the goddess Satet has drawn her arrow at Hathor (Sirius). Known as „Tir”, the star was portrayed as the arrow itself in later Persian culture.
SUMER. In the Sumerian Civilization, predating the Egyptians, their epic poem Epic of Gilgamesh describes a dream of Gilgamesh where the hero is drawn irresistibly to a heavy star that cannot be lifted despite immense effort.
This star descends from heaven to him and is described as having a very ‘potent essence’ and being „the God of heaven”. Gilgamesh had for his companions, 50 oarsmen in the great ship, Argo, a constellation bordering Canis Major, where Sirius is found.
MUSLIM – QUR’AN. The Quran mentions Sirius in Surah 53, An-Najm („The Star”), of the Qur’an, where it is given the name (al-shi’raa.) The verse is „That He is the Lord of Sirius (the Mighty Star).” (53:49); Yusufali: That He is the Lord of Sirius (the Mighty Star); Pickthal And that He it is Who is the Lord of Sirius; Shakir: And that He is the Lord of the Sirius.
POLYNESIA. Just as the appearance of Sirius in the morning sky marked summer in Greece, so it marked the chilly onset of winter for the Maori, whose name Takurua described both the star and the season. Its culmination at the winter solstice was marked by celebration in Hawaii, where it was known as Ka’ulua, „Queen of Heaven”. Many other Polynesian names have been recorded, including Tau-ua in the Marquesas Islands, Rehua in New Zealand, and Aa and Hoku-Kauopae in Hawaii.
Bright stars were important to the ancient Polynesians for navigation between the many islands and atolls of the Pacific Ocean. Low on the horizon, they acted as stellar compasses to assist mariners in charting courses to particular destinations. They also served as latitude markers; the declination of Sirius matches the latitude of the archipelago of Fiji at 17¡S and thus passes directly over the islands each night. Sirius served as the body of a „Great Bird” constellation called Manu, with Canopus as the southern wingtip and Procyon the northern wingtip, which divided the Polynesian night sky into two hemispheres.
INDIANS – NORTH AMERICA & ALASKA. Several cultures also associated the star with a bow and arrows. Many nations among the indigenous peoples of North America also associated Sirius with canines; the Seri and Tohono O’odham of the southwest note the star as a dog that follows mountain sheep, while the Blackfoot called it „Dog-face”. The Cherokee paired Sirius with Antares as a dog-star guardian of either end of the „Path of Souls”. The Pawnee of Nebraska had several associations; the Wolf (Skidi) tribe knew it as the „Wolf Star”, while other branches knew it as the „Coyote Star”.
DISCOVERIES. Based on changes in its proper motion, in 1844 Friedrich Wilhelm Bessel deduced that Sirius had a hidden companion. In 1844 German astronomer Friedrich Bessel deduced from changes in the proper motion of Sirius that it had an unseen companion. Nearly two decades later, on January 31, 1862, American telescope-maker and astronomer Alvan Graham Clark first observed the faint companion, which is now called Sirius B, or affectionately „the Pup”. This happened during testing of a 18.5 inch aperture great refractor telescope for Dearborn Observatory, which was the largest refracting telescope lens in existence at the time, and the largest telescope in America.
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 solar masses. 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.
In 1909 Ejnar Hertzsprung suggested that Sirius was a member of the Ursa Major Moving Group, based on the systems movements across the sky. However, more recent research by Jeremy King et al. at Clemson University in 2003 questions whether that is true, since the two components of Sirius appear to be too young. Sirius is roughly half the age of the other members of the stream, so their common motion is most likely a coincidence. In 1915, Walter Sydney Adams, using a 60-inch (1.5 m) reflector at Mount Wilson Observatory, observed the spectrum of Sirius B and determined that it was a faint whitish star. This led astronomers to conclude that it was a white dwarf, the second to be discovered.
This means that Sirius B must have originally been by far the more massive of the two, since it has already evolved off the main sequence. In 1920 the first spectrum of Sirius B was obtained at Mount Wilson Obvservatory. Sirius B although small and faint and about 10,000 times dimmer than Sirius A is extremely dense and heavy enough to exert influence on Sirius A. The pull of its gravity caused Sirius’ wavy movement.
The diameter of Sirius A was first measured by Robert Hanbury Brown and Richard Q. Twiss in 1959 at Jodrell Bank using their stellar intensity interferometer. In 1970 the first photograph was taken of Sirius B by Dr. Irving W. Lendenblad of the US Naval Observatory. In 2005, using the Hubble Space Telescope, astronomers determined that Sirius B has nearly the diameter of the Earth, 12,000 kilometers (7,500 miles), with a mass that is 98% of the Sun. The Voyager 2 spacecraft, launched in 1977 to study the four Jovian planets in the Solar System, is expected to pass within 4.3 light years of Sirius in approximately 296,000 years time.
Could there be a Sirius C? In 1995 two French researchers, Daniel Benest and J.L. Duvent, authored an article in the prestigious journal Astronomy and Astrophysics with the title Is Sirius a Triple Star? and suggested (based on observations of motions in the Sirius system) there is a small third star there. They thought the star was probably of a type known as a brown dwarf and only had about .05 the mass of Sirius B.
In visible light Sirius A (Alpha Canis Majoris) is the brightest star in the night sky, a closely watched celestial beacon throughout recorded history. Part of a binary star system only 8 light-years away, it was known in modern times to have a small companion star, Sirius B. Sirius B is much dimmer and appears so close to the brilliant Sirius A that it was not actually sighted until 1862, during Alvan Clark’s testing of a large, well made optical refracting telescope. For orbiting x-ray telescopes, the Sirius situation is exactly reversed, though.
A smaller but hotter Sirius B appears as the overwhelmingly intense x-ray source in this Chandra Observatory x-ray image (lines radiating from Sirius B are image artifacts). The fainter source seen at the position of Sirius A may be largely due to ultraviolet light from the star leaking into the x-ray detector. With a surface temperature of 25,000 kelvins, the mass of the Sun, and a radius just less than Earth’s, Sirius B is the closest known white dwarf star. Can you guess what makes Sirius B like Neptune, the Sun’s most distant gas giant planet? While still unseen, the presence of both celestial bodies was detected based on their gravitational influence alone …making them early examples of dark matter.
PSEUDOSCIENCE. In Theosophy, it is believed the Seven Stars of the Pleiades transmit the spiritual energy of the Seven Rays from the Galactic Logos to the Seven Stars of the Great Bear, then to Sirius. From there is it sent via the Sun to the god of Earth (Sanat Kumara), and finally through the seven Masters of the Seven Rays to the human race.
Its kabbalistic symbol was listed by Heinrich Cornelius Agrippa. Sirius is a BLUE-white star – the color of electricity. Reality is created by electromagnetic Consciousness grids. Ancient aliens from Sirius were allegedly BLUE – their descendants thought of as bluebloods or royalty.