Southern Sagittarius

Although there are many visible stars in these four constellations, there are few bright stars, and they are all located in the southern sky, which is not easy to observe. The declination at the stern is-1 1 to -5 1, and most of this constellation can hardly be seen in Beijing. The declination of the keel is-51to-75, which is absolutely invisible in Beijing!

The apparent magnitude of Carina Alpha is-0.72m, which is the second brightest star in the whole day. In the south of China, in the early spring evening, near the southern horizon, we can find it. (If you want to find it, you can take Sirius Canis as the midpoint, and Betelgeuse, the bright star of Orion, is in the north and west, and the distance between the south and the west is similar. ) Alpha carina was called "Old Man Star" in ancient China, and it was the symbol of the longevity.

In the south of China, connecting ξ star and ζ star in the tail area, and extending to the south for half of their distance, you can see ξ star in Vela. In the north of China, although you can see half of Vela, it is difficult to see the brighter gamma star of Vela.

The brightest star in the compass is only 4m, which is really a dark constellation with no visible image. Constellation myth: Ptolemy originally called tailstock, Vela and Carina the same constellation (excluding compass), called Argonavis. /kloc-In the 8th century, astronomers thought that the Southern Constellation occupied too much space, so they took it apart. The ship to the south is Argo. In the story, Jason took fifty people aboard Argo to Korcz in the Black Sea to find golden fleece.

The carina rises to the zenith at midnight at the end of each year 1, and part of it is located in the Milky Way, just south of Sirius and Nanhesan. Residents living in the area south of north latitude 15 degrees can see the complete base of the ship. There are many bright stars in Carina, the brightest of which is second only to Sirius. Its China star is called "Predecessor", and westerners call it "Seniors", which means "the ship navigator of Spartan King Menareus". The old mill is about 200 light years away from us. Its luminosity is 6000 times that of the sun, its diameter is 46 times that of the sun, and its mass is 12 times that of the sun. Astronomers estimate that the surface temperature of this old star is about 7460K according to its spectral model. There is a large nebula NGC 3372 in Carina (also known as "Carina Large Nebula"). Its appearance has been changing for a long time, and it is home to many massive stars. The most active celestial body in the nebula is "Haishan Erxing", that is, the star η of Carina, which briefly became one of the brightest stars in the whole day in the 1930s of 19, and then immediately dimmed.

The keyhole nebula is located in the middle and lower part of NGC 3372. There are several very massive stars inside it, which makes its appearance change all the time. NGC 3372 is about 7000 light-years away and about 300 light-years in size. There may be a violent supernova explosion in the next few thousand years. This dense mass of gas and dust is dissipating. It is estimated that it may take millions of years for the intense radiation from bright stars to completely evaporate them. These clouds in the picture are separated from the carina nebula, a star-forming region, which is 8,000 light years away. In Figure 4, you can also see newly formed stars, which are affected by the ubiquitous dust. Most of the blue light emitted is scattered, so it looks red. This unusual color photo covers an area of about 2 light years. The cloud column on the left side of the photo separated from the carina nebula is of particular concern. It looks like a superman hands in the air flying over the nebula, and the rescued person clings to his ass.

The carina planetary cloud Henize 3_40 1, which is about 1 10,000 light years away, is the narrowest planetary nebula known. For a spherical star, it is strange to produce a nebula of this shape, which some scientists think is strange. Its long and narrow shape may be a clue to solve the mystery of the outer material ejection mechanism in the later stage of the star. After thousands of years, the nebula will dissipate, leaving only a white dwarf. Center position: 9: 40 right ascension, -47 degrees declination. North of carina, in the Milky Way between Centauri and stern. Among them, there are 146 stars brighter than 6-magnitude stars, including 3 second-magnitude stars, 2 third-magnitude stars and 14 fourth-magnitude stars. Every April 10 at 8 pm, Vela goes to heaven. The gamma star Sagittarius (Tian She I) is an optical binary star with a magnitude of 1.8. It is one of the famous hot stars with a surface temperature of about 25,000 degrees Celsius. Its sub-star γ2 has a magnitude of 1.78, which is 800 light years away from us and is one of the brightest 200 stars in the whole day. Another sub-star, γ 1, has an apparent magnitude of 4.27, and is a blue-and-white sub-giant of type B1Ⅳ. The angular distance between two stars is 41".2". Daughter star γ2 is the brightest Wolf-Rayet stars in the whole day. Wolf-Rayet stars is a special type of star discovered by French astronomers Wolff and La Yexing in Cygnus on 1867. There are many broad emission lines in their spectra. Later, it was observed that Tian She-1 was a tetrad star, and the other two subsatellites were 8.5 and 9.4 respectively. It is reported that about 1 10,000 years ago, a nebula numbered NGC2736 in Vela exploded, forming a supernova remnant and causing a very obvious and strange bright spot. The outer layer of this new star hit the interstellar matter, producing a shock wave that is still visible today. The remnant of this nebula was first discovered by scientist Sir John Herschel in 1840, and it was named "Pen" nebula. The Vela cluster RCW38 is only 6000 light years away from us, and it has many stars with very strong radiation. These young stars with a history of only one million years have a hot atmosphere.

AIVelorumtypevariablestar: an ultrashort periodic pulsating variable with spectral type A ~ F, located in the unstable region of Cepheid variable on Herold diagram. The shape of light curve is similar to RR variable star in Lyra, and there is a beat period. When the light changes, the color index and spectral type change, forming a closed curve on the bicolor map. A typical star is AI in the constellation Vela, with a light amplitude greater than 0.3 magnitude and a period shorter than 0.3 days. In the past, it was thought that the absolute apparent magnitude was around +4, which was much darker than Cepheid variable and RR variable in Lyra, so it was also called dwarf Cepheid variable. Some people think that from the perspective of star evolution, it is in the pre-white dwarf stage; After passing through the red giant stage, it once lost a lot of matter, so its mass is very small, which may form a continuous transition group with the delta variable star of Shields. However, it has also been pointed out that the masses of these two kinds of variable stars are about two solar masses, and the only difference lies in the different pulse modes. The Latin name of coccyx is Puppis, the right ascension is from 6: 02 to 8: 26, and the right ascension is-1 1 to 5 1. The tail region is located on the east side of the connection between Sirius and carina, and most of it is located in the Milky Way. Among them, 18 1 star is brighter than 6, including second-class star 1 star, third-class star 6, and fourth-class star 14. Every March 13, at 8 pm, the stern will go to Zhongtian. Observers can see the complete comet tail south of 39 north latitude, but they can't see this constellation at all north of 79 north latitude. ζ star Lyra (named "Sagittal Augmentation 22" in the middle) is a hot and bright blue and white Supergiant star with a magnitude of 2.25 and a distance of 240 light years. It is a variable star similar to the beta star Lyra, with a brightness of 4.92 to 4.35 and a light variation period of 1 day 10 hour, 54 minutes and 27.6 seconds. The tail star τ (named "Old Man Zeng Yi" in the middle) has a magnitude of 2.93, which is 0/20 light-years away from us/kloc-. The magnitude of the tail ξ star is 3.34, and the distance is 1200 light years. The magnitude of the ponytail π star is 2.70, which is light-years away from us 100. The tail ρ star (middle name "sagittal increase of 32") is 93 light years away from us. It is a variable star with brightness ranging from 2.68 to 2.87. Kappa at the tail is a binary star system. The magnitudes of its two sub-stars are 4.5 and 4.7, respectively, the composite magnitude is 3.8, and the angular distance between the sub-stars is 9″.9.

There is a bright open cluster M93(NGC2447) at the northwest 1.5 of Mawei ξ star, with an apparent magnitude of 6.2 and about 80 member stars, with an age of 98 million years and a distance of about 3,600 light years. Not far from the northeast, there are two open clusters M46 and M47. M46 has an apparent magnitude of 6. 1, a distance of 5,700 light years, a member of about 100, and an age of about 300 million years. There is a planetary nebula NGC2348 in this cluster, and its apparent magnitude is 10. 1 etc. M47 has an apparent magnitude of 4.4, a distance of 1600 light years, 30 members and an age of 78 million years. On April 23rd every year, there will be a π meteor shower at the stern. The coordinates of the radiation point are 7: 20 right ascension and -45 declination. Ideally, the zenith flow is 10.

In ancient times, Sagittarius originally belonged to South Sagittarius. Sagittarius australis is a very huge constellation, which consists of carina, vela and tailstock. Later, it was divided into three by Lacaille. So there are no α, β, γ, δ and ε stars. Although the stars in this constellation are not bright, there are five bright open clusters, namely M46, M47, M93, NGC2447 and NGC225 1. This constellation also has an eclipse binary star V, which varies between 4.4 and 4.9.

Among the four open clusters in this constellation, M46 is the farthest from the Earth, which is 5,700 light years, which is about the size of a full moon. Next is NGC2274, which is 4200 light years away, but the stars are denser than any cluster in the constellation, so it needs a small telescope to distinguish them. There is an open cluster, M47, less than 3 degrees east of M46, but this cluster is only 1600 light years away from the Earth, and it is very dark, and M93 is even darker than it. The brightest star cluster in the constellation is NGC245 1, and its brightest star is a yellow Supergiant star of magnitude 3.6-Sagittarius C (Sagittarius III). Compass is one of the southern constellations. Latin name Pyxis, translated as compass, compass. Every year on March 2 1, go to Zhongtian at 8 pm. It is connected to Ophiuchus in the north, to Vela in the south, between the tail and the pumping station, and just at the midpoint between Ophiuchus Alpha (Ophiuchus I) and Carina. Part of the constellation is submerged in the Milky Way. The compass is a small constellation composed of a group of rather dark stars. The brightest stars in the constellation are three fourth-order stars. It is really a dark constellation and there is no image. Residents in the area south of 53 north latitude can see the complete compass, while residents in the area north of 73 north latitude can't see the constellation. Compass, sail, stern and base are collectively called "South Four Ships".

The Big Dipper is the most active star among the known circulating nova. Usually it is a dark star, with a brightness of 14. Every 18 to 24 years, the brightness increases by 1000 times (with irregular periodic changes), and the magnitude of dozens of stars increases to 6.5. Compass alpha star (named "Tiangou V" in Chinese), apparent magnitude 3.68, distance 1300 light years. It is a blue-and-white giant of B1.5 Ⅲ Ⅲ type. Compass beta (named "Tiangou IV" in Chinese) is a yellow sub-giant planet with an apparent magnitude of 3.97 and a distance of 180 light years. Compass γ (Chinese name "Tiangou Six") is a K3Ⅲ red giant with an apparent magnitude of 4.0 1 and a distance of 99 light years.

Greek mythology: It is said that dozens of ancient Greek heroes, led by Jason, sailed eastward in Argo, a seagoing ship, but found the priceless golden fleece. Athena, the goddess, lifted Argo into the sky and became the Southern Constellation after their long voyage and successful return to Greece. 1750, French astronomer Llakaj divided this ultra-wide southern constellation into base, stern, sail and mast. Later, because it was assumed that Argo needed a compass to navigate during the voyage, the mast was renamed the compass.

Interesting Star: Compass ε Star: This is a binary star system. The two subsatellites are +5.5 and +9.5 respectively, and are 7.8 arc seconds away from the Earth/kloc-0. Compass T: This is a metempsychosis nova. Its magnitude is usually about+14, but it can reach +7 when erupting. The eruption time may last more than 100 days, and the first eruption time is 1966.