Sirius, Bayer NoCanis Major alpha(Alpha Canis Majoris, abbreviated asα CMa）, the brightest star in the night sky, with an apparent magnitude of -1.46, almost the second brightest star in the whole dayElderly StarTwice as much.Its English nameSirius(/ˈ s ɪ ri ə s/) is derived from the Greek "ˈ ɪ ə", meaning "light" or "heat".[15]
Sirius is abinary star , which is composed of a main sequence star (Sirius A) with spectrum type A0 or A1 and a weak white dwarf star (Sirius B) with spectrum type DA2.The distance between the two is 8.2 to 31.5Astronomical unitChange every 50 years.Sirius system is only 2.64 away from EarthSecond gap(8.6 light years) is one of the closest star systems to the solar system.[15]Moreover, Sirius is gradually approaching the solar system. It is estimated that its apparent magnitude will reach a peak of - 1.68 in 60000 years.Coincidentally, at about the same time,Sirius will become Earth'sAntarctica。This year, Sirius andSouthern Celestial PoleThe distance will be reduced to within 1.6 degrees.[16]
Sirius looks so bright, on the one hand, because its luminosity is about 25.4 times that of the sun, on the other hand, because it is close to the solar system.However, withRigel(120000 times sunlight)Elderly Star(10700 times solar luminosity), evenArcturus(170 times sunlight) andCapella(78.7 times the solar luminosity) and other bright stars, Sirius is not very bright.[15]
Chinese name
Sirius
Foreign name
Sirius Aschere[17]
Alias
Alpha Canis Majoris、Canis Major alpha、Canis Major 9[14]
Sirius, alpha Canis Major[17](α Canis Majoris), located atCanis Major。SirianApparent magnitude- 1.46, the brightest star in the whole day except the sun, but darker than Venus andJupiter, most of the time bright than Mars.Sirius is a blue and white starMain sequence star, there is a white dwarfcompanion, SystemcentroidIt is about 8.6 light-years away from the earth.amongSirius B , that isWhite dwarfThe companion star is the first white dwarf observed by human beings, and it is also one of the white dwarfs with the largest mass.[1]
Because of its position as the brightest star in the whole day and nightancient civilization Sirius has a special status and a large number of records.
physical property
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Sirius A
Sirius position and volume
Sirius A is aBlue dwarf, the radius is about 1.711 R ⊙.Optical interferometerMeasure the radius of the star and estimateAngular diameter5.936 ± 0.016 mas.Its rotation speed is about 16 km/s, so it does not effectively flatten the star into an ellipse.VegaIt rotates at a higher speed of 274 km/s, making itOblate sphere。
The celestial model indicates that Sirius A was formed onceMolecular cloudAt the time of collapse, its energy generation has completely changed fromnuclear fusionYes.Its core has becometroposphereAnd utilize C-N-O cycle to produce energy.It is predicted that Sirius A will exhaust the hydrogen stored in the core within 1.76 × 10 ^ 9 years after its formation.It will experienceRed GiantAt that time, the luminosity of Sirius A will increase greatly.Then it will soften and become aWhite dwarf。
The spectrum of Sirius A has deep metal lines, showing the enhancement of some elements heavier than helium (such as iron), so it is also classified as Am star.Compared tosunlight, Sirius AatmosphereThe iron content relative to the hydrogen content is Fe/H=0.5, also equal to 10zero point five, which means that the content of iron in its atmosphere is 316% of that of the sun.Because it's unlikely that the whole star is richmetallic elementTherefore, these metal elements may be suspended on a thin troposphere on the surface.[8]
Sirius B
Sirius B has a mass greater than that of the sun and is the largest known massWhite dwarfone of.It is almost 1.1 M ⊙.However, so much material has been compressed to the size of the earth.hissurface temperature 25000 ± 200 K.However, since there is no energy generated inside, the remaining heat will radiate out of outer space in the form of radiation, and Sirius B will eventually gradually cool down, which will take more than 2 × 10 ^ 8 years.
A star passes byMain sequence starandRed GiantThe stage will becomeWhite dwarf。About 1.2 × 10 ^ 8 years ago, Sirius B may be a higher luminosity starBlue dwarf, the spectrum is between B4-B5, and the mass is about 5M ⊙.When Sirius B becomes a red giant, its companion star Sirius A'sAmount of metal。
Sirius B was originally composed of carbon andoxygenElement composition. These two elements are produced by helium nuclear fusion in the dead star that formed Sirius B.These elements are covered by lighter elements and layered according to mass, because Sirius B has high surface gravity.Therefore, the outer atmosphere of Sirius B is almost pure hydrogen, the lightest element in the universe, and no other element can be found in the spectrum.[9]
System
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Sirius and its companion are in aEccentricityThe larger tracks revolve around each other,Revolution period50.1284 ± 0.0043 years, with an average distance of about 20 AU.In the early days of this system, they were thought to be two blue and white stars, circling one every 9.1 yearsElliptical orbitfunction.[4]
In 1909, Eichener Herzpoon proposed that Sirius wasMoving constellation Ursa MajorHe came to this conclusion after observing the path of Sirius system in the sky.
ursa majorMoving clusterIt is composed of 220 stars and has the same path in space.It was originally formed asOpen clusterFrom then on, it gradually disengages from the traction of gravity.However, the analysis made in 2003 and 2005 shows that Sirius may not belong to this cluster.The estimated age of the moving star cluster in Ursa Major is 4 × 10 ^ 8~6 × 10 ^ 8 years, while the metal content of Sirius is similar to that of the sun, so the age may be only 2 × 10 ^ 8 years, which is too young for this star cluster.
Sirius may also belong to a possible "Sirius cluster", and the open stars that may belong to this cluster areAurigaβ、Northern Corona alphaGrand Duchessβ、Eridanaβ and Serpentine β.This cluster is one of three clusters within 500 light years of the sun.The other two areBistar clusterandPleiades, each with hundreds of stars.
Observation history
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Sirius is the brightest star at night, so it is recorded in the earliest astronomical records.
China
In the ancient Chinese astronomical system, this star was called Sirius (the wolf in the sky)“28 constellations”In, Sirius belongs towell , and theSirius Officer。SiriusStar officialThere is only one star in it.
Of course, the Chinese ancients also paid attention to this bright star, and called it "Wolf Star", the most eye-catching star in Jingsu, south of Queqiu. In the past, this star referred to invading aliens, and its changes in light and shade foreshadowed the security of the border.Therefore, for the sake of territorial peace, the ancients set up aShoot Sirius's bow -“sagittal ”The bow and arrow composed of these nine stars are very vivid. The arrow is on the string, the bow has been drawn round, and the arrow points directly to the "Wolf Star" in the northwest.Su ShiZeng Zuo described this vividly:“Can draw a carved bow like a full moonLook northwest and shoot Sirius. "But thisLongbowIts main function is to deter the "wolf" by force. The real means of capture is not far from its west“Military city”A wolf trap surrounded by 13 stars.In order to lure Sirius, the hunter also placed a special trap“pheasant”1 star as bait.[2]
The ancients willStern seatandCanis MajorSome of the stars in the sky are combined and imagined as a big bow across the southern sky, and classified intoSagittarius Star OfficerMedium.In this combination, the arrow is facing Sirius.It means "shoot Sirius".This is how the sentence "Look to the northwest and shoot the Sirius" in Jiang Chengzi Hunting in Mizhou comes from.As for the Sagittarius officials, the ancients also had a saying: the heavenly bow is stretched, and the world is full of soldiers.That is, astrologers use it to forecast military situations.
Similar combinations are also found in Dendera, EgyptHathor Temple It appeared on the mural.At a later stagePersian cultureThis star is called Tir and is used as an arrow.Saudi ArabiaThe goddess who painted her arrow on the head of a cow and the body of a human beingHathor (Sirius).
October 8-12, 2022,Zhishen StarTravel with Sirius.[13]
Ancient Egypt
A bust of the Egyptian goddess Sirius and the Nile fertility goddess Supdet
Because Sirius andCelestial equatorIts moving period in the starry background is almost the same as that of a year, which makes it rise on July 19 almost every year.Coincidentally,the NileUsually after that, it will start to flood. The silt brought by the flood will make the fields along the river become fertile, which makes the ancient Egyptians regard Sirius as a goddessSOPODETTE(Sopdet, ancientEgyptianSpdt，Means“triangle"), bless their fertile land.[3]The cycle of Sirius is still slightly different from that of the solar year, which may have led to the discovery of the 1460 year SoTHIC cycle by the ancient Egyptians and affected the development of the Julian and Alexandrian calendars.
ancient Greek
The ancient Greeks believed that the appearance of Sirius predicted a hot and dry summer, and people worried that the appearance of Sirius would lead to plant withering, male weakness, and femaleSexual arousal。Sirius will shine more brightly in the unstable weather conditions in early summer, which means that for Greek observers, it means the radiation causing its malignant effects.Any person affected by it is called a "star impact" (ἀ τ ρ o β ό λ ηττ ο, astrob ó l ∨ tos).It is described as "burning" in literature.The season after Sirius reappeared is called "Dog Day".aegean seaThe residents of Ceos in the Middle Kingdom willZeusSacrifice to bring cool breeze and wait for the stars to reappear in summer.If the weather is sunny, it indicates good luck;If it is foggy or faint, it indicates (or emits)plague。[4]
Ancient Rome
In the 3rd century BC, the Roman coins found on the island of Saios had dogs or stars shining, which highlighted the importance of Sirius.The Romans also noticed SiriusRegularityThe appearance of, celebrated the disappearance of Sirius around April 25, sacrificed a dog, andIncense、WineAnd a sheep, so that the radiation of Sirius will not be caused on the wheat crop of that yearWheat rust。
In Scandinavia, people in northern Europe once called Sirius "Locabrina", meaning "burned by Loki" or "Loki's torch"[4]
In 1844, German astronomerBessel According to the wave pattern appearing in its moving path, it is inferred that Sirius is a binary star, because the star moves along a wavy track in nearby space, so it has acompanionAnd the rotation period is about 50 years.This companion star was refracted by American astronomer A. Clark in 1862Astronomical telescopeFirst to see.[5]
In 1868, Sirius became the first starMeasuredThe speed of the star, this is the research objectradial velocity The beginning of.William Huggins Sir examined the spectrum of the star and observedred shift。He concluded that Sirius is moving away from the solar system at a speed of about 40 km/s, while the modern measurement results are - 5.5 km/s（minus sign"−" means it is approaching the sun).This is an extremeinaccurateIt is possible that Hawkins did not consider the Earth's orbital speed, which will lead to an error of up to 30 km/s.
Since 1894, some obvious orbits have been observed in the Sirian systemIrregularitiesThis indicates that there is a third very small companion star, but this has never been confirmed.For dataBest FitIt shows that the orbit around Sirius a is 6 years, and the mass is 0.06m ⊙.This star willWhite dwarfSirius B Dark 5 to 10 orders of magnitude, which will make observation difficult.The observations published in 2008 could detect neither a third star nor planets.An obvious "third star" observed in the 1920s is now considered as the background object.[6]
Observation guide
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Find Sirius
Sirius is very bright, almost the second brightElderly StarAs long as there is no cloud cover, it is easy to see, even in bright cities.Sirius can be observed from almost any place on the earth where people live, except those who live north of 73 ° north latitude.Of course, Sirius observed in some cities in the north of the earth will not rise very high, such asSt.PetersburgSirius will only rise tohorizon13 ° above.Because of SirianDeclinationAbout - 17 °, so fromSouth LatitudeFrom 73 °, it is aArched polar star。From the southern hemisphere in early July, Sirius can be seen descending after sunset and rising before sunrise.The sky must be very clear, the altitude of the observation site must be high, the sun must be low on the horizon, and Sirius must be overhead, which is very rare.Sirius appears longer at night only in winter or early spring.There are several ways to find Sirius:
Through Orion
Canis Major
OrionIt is very easy to find, and the Samsung closely aligned between its two bright stars should also be visible.Seen from the three stars to the southwest, a very conspicuous star is Sirius.Walking along the hunter's belt, the three stars patrolled to the southeast and saw an extremely bright star shining blue and white light. This is the brightest star in the night sky: Sirius,Apparent magnitudeUp to -1.46, etc.SiriusCanis MajorAlpha star, which forms the outline of a dog with some other bright stars in Canis Major. Sirius is on the dog's mouth.[7]
Through the Winter Triangle
This method is not so intuitive.The bright star on the upper left of OrionBetelgeuseThere is a brighter one in the eastNanhe IIIThe connecting line between Nanhe 3 and Betelgeuse 4 goes southVertical bisectorWill find him.Betelgeuse, Sirius and Nanhe form the famous“Winter Triangle”。
The above two methods are commonly used. In fact, the simplest way to find Sirius is to look at the southern sky around 22:00 in the evening before and after the Spring Festival. The brightest star is Sirius. Of course, the premise is to exclude the planets.The orbit of planets in the night sky is generally similar to that of the moon, and Sirius is low.In China, the orbit of Sirius is always in the lower part of the southern sky.The farther north Sirius goes, the lower its altitude angle.[7]
Observe Sirius B
Sirius basedbinary star The minimum separation distance between the two stars is 3Angular secondThe maximum division distance is 11 seconds.When they are closest to each other, it is very difficult to distinguish two stars during observation, becauseWhite dwarfSirius B is close to it, but there is a much brighter Sirius A
In 1994, two stars reached theirArch pointSince then, this pairKonductraStart to stay away from each other withAstronomical telescopeIt is easier to separate them.With a distance of 8.6 ly from the Earth, Sirius A and Sirius B occupy two of the eight stars closest to the solar system, and they are the fifth to the solar systemStellar system。
To separate them clearly, an astronomical telescope with an aperture of at least 300 mm is required, except for ideal weather.[7]
Name Source
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Sirius astronomical coordinates
Sirius is commonly known as Sirius in English, which comes fromGreekΣείριος，It means "scorched", because the ancients believed that it was summer when Sirius and the sun rose at the same time, and the combination of the light of Sirius and the sun was the reason for the hot weather in summer.thisancient GreekWords may also be in GreeceClassical periodIt developed from somewhere before.The earliest discovery and use of this name dates back to the 7th century BCHesiodIn his poem Work and Time.The ancient Greeks called summer "Dog Day", because only dogs can run out in such hot weather like crazy, so this star is also called "Dog Star".Ancient EgyptSirius is called Sothis, which means "the star on the water".
Sirius has more than 50 other numbers and names.stayArabicSirius is called "ㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆㄆ.In Sanskrit, Sirius is Mrgavyadha ("deer hunter") or Lubdhaka ("hunter").When called Mrgavyadha, Sirius representsRudra (Shiva);stayScandinaviaSirius is regarded as Lokabrenna ("the fire Loki put down" or "Loki's torch").In the Middle AgesastrologySirius is aBehenian fixed star.[10]
Cultural characteristics
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Chinese culture
In ancient Chinese astrology, Sirius belongs towell Su Shi is the evil star of "the threat of aggression"《Jiangchengzi》In the "will draw a carved bow like a full moon, look northwest, shoot Sirius", compare the threat with SiriusNorthern Song DynastyNorthwest frontierXixia。[11]If you think it's from where Su Shi wasgeographical position"Look northwest", that's wrong.Because Sirius is in the southern hemisphereNorthern HemisphereIt is definitely not located in the northwest.Justice: "The arc nine stars are in the southeast of Wolf, and the bow of heaven is also." The Song History Astronomy: "The arc nine stars are in the southeast of Wolf, and the bow of heaven is also." That is to say, Sirius is in the northwest of the arc.Therefore, Su Shi used "looking at the northwest" to say from the position of nine stars.[12]
Ancient Egyptian Culture
MeasuredarchaeologistThey found that ancient EgyptPyramidIt was conceived and built from the perspective of astronomy, in which Sirius is one of the stars related to the pyramid. However, it is precisely this kind of attention to Sirius that makes people feel quite strange, because people want toMemphisWhen the city observes Sirius, it can only be seen in the dim dawn near the horizon at the beginning of the Nile flooding.There is a detailed book in Egyptalmanac(written in 421 BC), based on the rise of Sirius (first appeared on July 19), and determined thatAnnual cycleAbout 3.2 × 10 ^ 4 years.In Egypt, almost allReligious architectureAnd the orientation of funeral buildings have astronomical significance.Used by EgyptiansCollimatorOne of the celestial bodies targeted is Sirius, and many temples are facing this star, such as Dandera'sHathor Temple 。
Sirius (hypothetical picture)
Sirius is the brightest star in the night sky, easy to find.In ancient Egypt, Sirius reappeared in mid July every year.Before sunrise, it appeared in the twilightIn the morning light, shining in the Egyptian sky.However, it happened that the annual Nile flood, an important event indispensable to Egyptian life, also took place at this time.Every year in mid July, when Sirius rises in the east before dawn, the Nile begins to flood.Some silt overflowed the riverbed with the river, moistening the surrounding land.When the tide receded, farmers began to sow on fertile soil.Egyptian ownedagricultural productionAre closely related to the ebb and flow of the Nile.Therefore, the Egyptians regarded Sirius as a god and worshiped it. Even the orientation of the temple built should be consistent with the rising place of Sirius.
In addition, the ancient Egyptians loved to associate Sirius withIsisConnect knots.Isis isOsiris's sister and spouse, alsohorus Mother.There is a passage in the pyramid scripture, which is written for Osiris: "Your sisterIsisCome, you are happy, you love.You put her on top of you... Because of the baby, Isis grew up, just like Sept.Horus Sept was born in the name of the residents of Sept. "The most striking thing about this passage is that it implies her "dual identity" from "Isis has grown up because of having children".Not only that, after the birth of the child, Horos did not leave, but stayed to become a "resident of Sept".
As the pyramid scripture shows, Sirius is a double star.However, American astronomer Alvin Clark did not discover the existence of Sirius B until 1862 with the largest and latest astronomical telescope at that time.This is the first time that the world has seen Sirius B.How did the author of the pyramid scripture know thisUnsolved mystery。
The so-called cycle of Sirius is also the cycle of Sirius rising again at the same place as the sun.In a fixed season, Sirius disappears from the sky, and then rises again from the eastern sky before the sun rises.In terms of time, ifdecimal pointAfter removing the mantissa of, the cycle is 365.25 days.What is particularly surprising is that of the 2000 stars that we can identify with the naked eye, the only stars that rise at the same time as the sun are Sirius' "proper motion" (meaning the speed of this star's movement in the universe, that is,) andprecession of the equinoxesThe result of movement.At the same time, in the ancient Egyptian calendar, the day when Sirius was launched earlier than the sun was specially designated as New Year's Day.Previously, in Hyopolis (where the pyramid scriptures were written), the ancient Egyptians had already calculated the time of New Year's Day and announced all the temples on the Nile.
In the pyramid scripture, Sirius was named "Hername of the new year".All kinds of signs show that the Sirian calendar is at least as old as the pyramid scriptures, but the origin of both is unknown.The most puzzling thing for archaeologists is how the ancient Egyptians had profoundscientific knowledge, observed and recorded a very coincidental earth difference of 365.25 days between the sun and the cycle of Sirius.The French mathematician R. A. Schwaller Lubicz once said that the cycle of Sirius was "an unexpected celestial phenomenon completely unexpected".[4]
Roman culture
Sirius has special significance in many cultures, especially representing dogs.In fact, he is the brightest star in Canis Major, and is often called "Dog Star" in spoken language.He is also a dog in the traditional hunter myth: the ancient Greeks believed that the light of Sirius had a bad effect on dogs, making them appear abnormalSummer heat("Dog Day"): Their excessive panting leads to excessive dryness and danger of disease.In extreme cases,Foaming at the mouthYour dog may haverabies, which may lead to infection and death of the bitten person.The ancient Romans knew that these days were dog days and called this star Canicula.
Polynesia and other Pacific civilizations
Bright stars are very important for ancient Polynesians to sail in the Pacific Ocean, and they are also signs of latitude.Declination and declination of SiriusFiji IslandsThe latitude of 17 ° S matches, so it passes near the zenith of these islands every day.In the constellation system of Polynesians, Sirius is the main body of a "Big Bird" constellation called Manu, with the old man star on the south wing tip and the old man star on the north wing tipNanhe III, dividing the Polynesian night sky into two hemispheres.Just as Sirius appears in the morning sky to mark the summer of Greece, it marks the beginning of the Maori winter. The Maori name Takurua describes the stars and seasons.Many other Polynesian names have also been recorded, including Tau uaNew ZealandRehuaTahitiTa'urua-fau-papa (the festival of primitive high chiefs) and Ta'urua-e-hiti-i-te-tara-te-feiai (accompanied by prayer andreligious ritesAnd the rising festival).
Sirius's appearance at the winter solstice was celebrated in Hawaii, where it was called the "Queen of Heaven".Hawaiians have many names for Sirius, including Aa ("Luminous"), Hoku kauopae, Kau ano meha (also known as Kaulanomeha), "Independent and Sacred", Hiki kauelia or Hiki kauilia (nautical name), Hiki Kau loo meha ("Lonely Star of Lorno"),AstrologyName), Kaulua (also known as Kaulua ihai mohai, "the flower of heaven"), Hiki kauelia, Hoku hoo kele waa ("the star that sets the canoe off", a nautical name), and Kaulua lena（“Yellow Star”）。Society IslandsPeople on the Internet also have many names for Sirius, including Taurua fau papa, Taurua nui te amo aha and Taurua-e-hiti-i-tara-te-Feai.Other names of Sirius include Palolo mua (Futuna), Mangaia, Manihiki, Marquesas Islands and Pukapuka.In Tuamotus' astronomy, Sirius has various names, including Takurua TetUpp(Takurua te upuupu), te Kaha（“CoconutFiber "), Teupupu, Taranga, and Vero ma torutoru (" burning and reducing ").[4]
American culture
Far away, manyNorth AmericaOfaboriginesIt also connects Sirius with dogs;The indigenous people Seri and Tohnuohamu in the southwest note that this star is a dog following the sheep mountain, and the black foot is called "dog face". The Cherokee people refer to Sirius andAntares Make a pair of guard dogs at both ends of the soul road.NebraskaThe Boni people of;Wolves regard it as' wolf star ', while other tribes regard it as' wolf star'CoyoteStar '.To the northAlaskaBering StraitInuit calls this star "the dog of the moon".Some cultures associate this star with bows and arrows.
Perhaps because of historical and cultural reasons, or because of personal feelings, Sirius is destined to be a star that cannot be linked with romance and enthusiasm. You can watch the moon and see the moon with your lovers and friendsmeteor showerLook at Venus or Mars, but Sirius, pale and shining with blue light, cannot make people happy. Maybe it is because of this unique personality that it has attracted countless lonely hearts.[4]
