Big Dipper Seven Stars
The Big Dipper are the stars we are familiar with, located in the northern sky in the constellation Ursa Major, and are made up of seven bright stars. These seven bright stars are arranged in the shape of a spoon and can indicate the North Star, so we can easily distinguish the Big Dipper in the night sky.
The Big Dipper is not far from Earth, and they are about 100 light-years away. In the Big Dipper, except for the red giant star that is undergoing helium nuclear fusion, other stars are undergoing hydrogen fusion like the sun. Some of these stars belong to multiple star systems, for example, there is a companion star called "auxiliary" around Kaiyang, which is visible to the naked eye, and there are four invisible companions, so Kaiyang belongs to a hexagram system.
Currently, there is no evidence of planets around the Big Dipper. But there was a dust disk around Tianxuan, and there might be planets there.
Nandou six stars
In the southern sky, there is also a "spoon" that echoes with the seven stars of the Big Dipper, which is the six stars of the Southern Dipper. The Nandou Six Stars are the six bright stars in the constellation Sagittarius, and their arrangement resembles a spoon, hence the name Nandou Six Stars.
So, what are the six stars of the Nandou? What do they have to do with the Big Dipper?
Tianfu Star
In modern astronomy, Tianfu Star is also known as Dou susan or Sagittarius ζ. With an apparent magnitude of 2.59 and 88 light-years from Earth, Douju vi is actually part of a triad system. The two larger stars, Douju VI A and B, form a binary system with a total mass of 5.3 times that of the Sun and orbit each other for 21 years. The Douju-6C is smaller , and it orbits the binary system in the distance , forming a triad system.
According to the measurements, Dou Su Vi is currently moving away from the solar system at a speed of 22 km/s. This star system was once so close to us that it was only 7.5 light-years from Earth about 1 million years ago.
Celestial Star
Celestial Star, also known as Τ Or τ Sagittarius, is located 122 light-years from Earth. It has a mass of 1.3 times that of the Sun, a radius of 15.7 times that of the Sun, and a luminosity of 88 times that of the Sun. Dou Su Wu is a giant star, much larger than the Sun, but the surface temperature is 1300 degrees lower than the Sun, only 4200 degrees Celsius, so it looks slightly orange.
It is estimated that the age of Dou Su Wu has reached 7.9 billion years, which is much older than the sun. The star has exhausted the hydrogen in its core, begun helium fusion, expanding in volume, and evolving into a red cluster of giant stars.
Celestial Star
Celestial Star, also known as Douju IV or Sagittarius σ, is located 228 light-years away from Earth. With an apparent magnitude of 2.05, Dou Su 4 is the brightest-looking star among the six stars of the Southern Dipper, ranking second in the constellation sagittarius.
It has a mass of 7.8 times that of the Sun, a radius of 4.5 times that of the Sun, and a luminosity of 3300 times that of the Sun. There is also a dim companion star around dousu, which is invisible to the naked eye. Compared with the Sun, Dou susi has existed for a relatively short time, about 31 million years.
The sky is the same star
Also known as Cesar or Sagittarius φ, it is located 239 light-years from Earth. The mass and radius of Dou Su Yi are about 4 times that of the Sun, the luminosity is 475 times that of the Sun, and the surface temperature reaches 14,700 degrees. It appears to have a companion star, but only an optical companion, not a physical companion, and it is likely to be a single star like the Sun.
The "Teapot" constellation in sagittarius
Celestial stars
Celestial stars, also known as Cesar ii or λ Sagittarius, are located 78 light-years from Earth. Dousu II has a mass of 2.6 times that of the Sun, a radius of 11 times that of the Sun, and a surface temperature 1000 degrees lower than that of the Sun. The star is close to the ecliptic in the sky, so it is possible that it will be obscured by planets in the solar system, creating a masking phenomenon.
Seven killing stars
Also known as DouJuichi or Sagittarius μ, it is the furthest star in the Six Stars of the Southern Dipper, with a distance of 3,000 light-years, which is farther away than most of the stars visible to the naked eye. Because Dou Su Yi is very bright, even if it is far away, it is still visible to the naked eye. Douju has a mass of more than 14 times that of the Sun, a radius of 68 times that of the Sun, and a luminosity of up to 200,000 times that of the Sun.
Observations have shown that Dou sustenance is a quadrangle star system. The main star Dou Su Aa and a close companion star Dou Su Yi Ab form a binary star system, although Dou Su Yi Ab is a bright star with a mass of up to 10 times the Sun, it is submerged in the dazzling light of the main star. The remaining companions are far away and have a very weak combination with the Dou su yi aa and Ab systems.
The constellation Sagittarius, where the six stars of the Southern Dipper is located, is a zodiac constellation, which is one of the most recognizable constellations in the summer night sky. Every year during the northern hemisphere summer, Sagittarius appears in the southern sky. The center of the Milky Way is located in this constellation, in which the Milky Way looks the largest and brightest.
Sagittarius
In reality, whether it is a star in the six stars of the Southern Dipper, or a star in the seven stars of the Big Dipper, or the six stars of the Southern Dipper and the seven stars of the Big Dipper, there is no direct connection between them. The stars in the South Dipper and the Big Dipper are very far apart, and the gravitational force between them is extremely weak and completely negligible.
In the South Dipper or Big Dipper, stars have their own systems, each moving in the Milky Way without being affected by other members. It's just that because they're relatively close to each other in the Earth's night sky and are arranged in a shape similar to a spoon, they'll be noticed by us.
The constellation changes over time
After hundreds of thousands of years, the respective movements of these stars in the Milky Way will fragment the six stars of the South Dipper and the seven stars of the Big Dipper.