Sirius (English: sirius) In ancient astronomy, the brightness of stars is divided by "magnitude". People divide the stars visible to the naked eye into six magnitudes according to their brightness. The brightest stars are called 1 The stars just visible to the naked eye are 6th magnitude stars. (We can see dimmer stars through a telescope) The brighter the star, the smaller the star. It is now stipulated that the magnitude difference is 5 magnitudes and the brightness difference is 100 times. In this way, an increase in magnitude by 1 will make it 2.512 times dimmer. However, there are several stars in the observations that are brighter than 1st magnitude stars. In order to avoid the trouble caused by modifying the magnitude, astronomers have expanded to zero and negative magnitudes. The brightest star Sirius is -1.45, while Venus at its brightest is -4.22, the full moon is -12.73, and the sun is -26.82. In this way, the brightest star that can be seen in the sky is Venus (planet), and Sirius is the brightest star that we see. In astronomy, we talk more about absolute magnitude, which is not the same thing as the brightness we see. It refers to the luminosity of a star. The absolute magnitude of Sirius is much brighter than the sun. The brightest star in the night sky has a visual magnitude of -1.45. It is a double star in the constellation Canis Major. The leonon star in the binary star is a blue-white star that is 23 times brighter than the sun. Its volume is slightly larger than the sun, and its temperature is much higher than the sun. It is about 8.6 light-years from the solar system, only twice the distance of the nearest star other than the sun. The ancient Egyptians recognized that the star rose with the Sun, which meant that the annual flooding of the Nile Delta began just before the sun rose. Moreover, they discovered that the time interval between Sirius rising with the sun was not 365 days in the Egyptian calendar year but 365.25 days. In 1844, the German astronomer Bessel inferred that Sirius was a binary star based on the wave pattern appearing in its moving path. Because the star moved along a wave-shaped trajectory in nearby space, he concluded that it had a companion star and orbited it. The conclusion is that the cycle is about 50 years. This companion star was first seen by American astronomer A. Clark in 1862 using his self-made 4.7m refractor telescope, which was the largest at the time. Sirius and its companion stars revolve around each other in highly eccentric orbits, with an average distance of about 20 times the distance between the sun and the earth. Although the bright star shines brightly, it is not difficult to see the 7th magnitude companion star with a large telescope. The companion star is about the same mass as the sun and much denser than the sun. It is the first white dwarf star to be discovered. Sirius is Alpha Canis Major and is the brightest star in the sky. Sirius is a visual double star composed of two stars, A and B. Star A is the brightest star in the sky and is a blue dwarf star on the main sequence. Star B is generally called the Sirius companion star. It is a white dwarf star with a mass slightly larger than the sun and a smaller radius than the earth. Its material is mainly in a degenerate state, with an average density of about 3.8×106/cubic centimeter. The orbital period of A and B is 50.090±0.056 years, and the orbital eccentricity is 0.5923±0.0019. Sirius is 8.65 ± 0.09 light years away from us. Whether Sirius is a close binary star is related to the evolution of the Sirius binary star. It was recorded in ancient times that Sirius was red, which provides us with research clues. X-rays from Sirius were discovered in 1975. Some people think that this may be thermal radiation from the deep atmosphere of the almost pure hydrogen atmosphere of Star B. Some people think that it may be generated by the high-temperature corona of Star A or Star B. This is still going on today. Research. According to data from 1980, the High Energy Observatory Satellite No. 2 measured the X-rays in the 0.15-3.0 kiloelectronvolt band of Star A and Star B respectively, and found that the X-rays of Star B were much stronger than those of Star A. In the winter sky, from the three stars of Orion to the southeast Looking in the direction, one of the brightest stars in the sky is shining there. It is the Alpha Canis Major star, which was also called Sirius in ancient my country. Sirius has an apparent magnitude of -1.45m and is only 8.6 light-years away from us. In ancient Egypt, every time Sirius rose from the eastern horizon at dawn (this phenomenon is called "rising" in astronomy), it was the time when the Nile River flooded once a year. The flooding of the Nile River irrigated the There were large areas of fertile land on both sides of the strait, so the Egyptians began farming again. Since the appearance of Sirius was closely related to agricultural production in ancient Egypt, people at that time regarded it as a god and determined the day when Sirius rose in the east before dawn as the beginning of the year. It can be said that the "Gregorian calendar" we use now was first born in ancient Egypt.
We know that the pyramids were conceived and built from the perspective of astronomy. Since ancient Egyptian astronomy is not well-known, doesn’t this opinion seem a bit forced? Sirius is one of the few planets related to the pyramids, but it is precisely this pairing The attention on Sirius is quite strange. Because when people want to observe Sirius from the city of Memphis, they can only see it in the vast morning light close to the horizon when the Nile River floods. There is a detailed almanac in Egypt - A.D. 421 BC, which is enough to make people feel confused! This almanac is based on the rise of Sirius (first appearance is July 19), and determines the annual cycle to be more than 32,000 years. We admit that ancient astronomers did not have no time After observing the sun, moon and celestial bodies for a long time, they finally reached a consensus and believed that all the celestial bodies would settle in the same place after about 365 days of movement. However, it is not absurd to deduce the first almanac from the data of Sirius ? Completely ridiculous! Because it is much easier for them to deal with the sun and moon, and they can also get more accurate results. The "Sirian Almanac" seems to be a product of pure assumptions, a calculation of probability, because It has indeed never been able to predict the appearance of a planet: the flooding of the Nile and the associated phenomenon, namely the appearance of Sirius on the dawn-shrouded horizon, were purely accidental. The Nile does not flood every year, and it does not always flood on the same day. Why did a "Sirius Almanac" appear? An ancient document also appeared in this regard? Are there any scriptures or promises that were carefully hidden as secrets by ancient priests? We have no way of knowing. In the constellation Canis, Sirius is the companion star of Sirius, the brightest star among them. It is the first white dwarf star discovered by humans. It is very small, about the same size as the earth, and invisible to the naked eye; but it is extremely dense, thirty thousand times larger than Mercury. It has a mass similar to that of the sun. This star was observed by astronomers using a telescope in 1862, and its identity as a "white dwarf" was determined in 1915, which attracted great attention from the astronomical community. However, at least 1,200 years ago, Mali, Africa The Duogen tribe began to worship the star, and knew its volume, density, orbital shape (elliptical) and the period of its orbit around Sirius (forty-nine Earth years), and recorded these in the woodcuts of this primitive tribe. , on murals and textiles. It is said that it was a god named "Nomo" who imparted the knowledge about the Sirius β star to the Dogan people. The Dogan people preserved a painting, which shows the god they believe in riding A large spaceship dragging flames descended from the sky and came to the Duogen tribe. Therefore, people speculated that the "Nomo" might be an alien who came to the earth from the Sirius β star (or a related star). Mention When it comes to the Sirius companion star β, we have to tell the story of what happened to it, because many major discoveries often start from some small "deviations". In the eighth century BC, an astronomer from the Tang Dynasty in China put his Comparing the observations with ancient records, it was found that the positions of the stars had changed. More than a thousand years later, in the 18th century, the British Halley also independently saw the same phenomenon. It turns out that the so-called immobile and unchangeable "stars" , Wrong name. The stars in the sky are moving and changing. In 1844, astronomer Bessel noticed that Sirius, the brightest star in the sky, moved strangely. Its path was undulating, unlike ordinary stars. Always moves evenly along a straight line. The astronomer concluded from this that Sirius is not a star, but a binary star system, and the other star is an "invisible" companion star; the undulating path is exactly It is the result of Sirius moving and rotating. Later, some astronomers studied the movement of Sirius and predicted the position of Sirius based on the law of universal gravitation. Twenty-eight years later, in 1862, they finally found the star in the telescope. The "invisible" companion star of Sirius was found. Compared with Sirius, this "invisible" companion star is too faint. In the telescope, it looks like an artifact caused by the defects of the telescope. But during observation When another object was found, this "flaw" disappeared, and everyone believed that they had found Sirius's "invisible" companion star. The two stars that make up the binary star are both called the sub-stars of the binary star. The brighter one is called The main star; the fainter one is called the companion star. Some of the brightness differences between the main star and the companion star are not much different, and some are very different. There are many double stars that are very close to each other. Even with the largest modern telescope, they cannot be separated. The two sub-stars can be distinguished. However, astronomers can find that they are composed of two stars using spectra obtained by spectroscopic methods. Such a binary star is called a spectroscopic binary star. Therefore, as mentioned above, the two sub-stars can be separated using a telescope The resolved double stars are accordingly called visual double stars. When some double stars orbit each other, a phenomenon similar to a solar eclipse will occur, causing the brightness of such double stars to change periodically. Such double stars are called eclipses Binary stars or eclipsing variable stars. Eclipsing binary stars are generally spectroscopic binary stars. There are also binary stars that are not only very close to each other, but also have matter flowing from one sub-star to the other. Such binary stars are called close binaries. Some close binary stars emit X-rays when matter flows, called Sex is of great significance, and it is also an indispensable aspect for understanding the formation and evolution of the Milky Way. Answered by: Feng Langhu