The retrograde orbit around Saturn (opposite to the rotation direction of the planet) is not clear whether it is a real satellite or just a stable fragment of the F ring. Some Trouvat asteroids use the same names as Saturn's moons: Pandora 55, Titan/KOOC-0/06, Rhea 577, Prometheus/KOOC-0/809, Epimetheus/KOOC-0/8/KOOC-0/0 and Pan 40. Edit this paragraph of Enceladus.
Enceladus is the smallest and closest of Saturn's eight large and regular moons. It has a diameter of 392 kilometers and an average distance of about 185520 kilometers from Saturn. The orbit is almost circular. The period of revolution is 23 hours long, which is exactly half of the period of revolution of Titan, so the two satellites always meet on the same side of Saturn. This phenomenon is called track vibration, and the reason is not clear. Enceladus' rotation and revolution are synchronous, so it always faces Saturn in the same hemisphere. This is similar to the relationship between the moon and the earth. The average density of Enceladus is only 1.2 times that of water, and its surface is characterized by freezing. For these reasons, it can be considered that the main component of Enceladus is ice. Its surface is bright and covered with bowl-shaped deep pits. The depth of the crater is very large, because the surface gravity is very small. The most striking surface structure on Titan is a crater with a diameter of 130 km, which is located in the center of the hemisphere facing Saturn. The mountain is 5km high and the bottom is10km deep. There is a 6-kilometer-long mountain peak in the center. This is the largest meteorite impact structure found in the solar system so far. Enceladus has an important dynamic influence on the structure of Saturn's rings. Enceladus revolves around Saturn for 22 hours and 25 minutes. If there is a particle in the gap of Cassini ring in Saturn's ring, its rotation period is exactly half that of Enceladus. According to the * * * vibration theory, some astronomers believe that the Cassini ring gap is the direct result of the gravitational disturbance of Enceladus. There are hydrogen clouds near Titan's orbit. Edit this passage of Enceladus
Enceladus is Saturn's third largest satellite. Before the American planetary probe Voyager 2 flew near this celestial body in 198 1 year, people not only knew its orbit, but also knew something else.
Encelados
Know nothing. When the probe approaches 87 140 km, it is found that Enceladus has a complex geological structure. Observations show that Enceladus has gone through five different evolution periods. The age of several crater-free areas does not exceed 1 100 million years. Because this period only accounts for 2% of Enceladus' whole life, it seems that it is still an "active" satellite. The energy to continue this geological activity may come from Saturn and the tidal force of Titan. Enceladus has a diameter of 500 kilometers and revolves around Saturn in a circular orbit, with an average distance of 238,020 kilometers from Saturn. The average density is only 10% higher than that of water, indicating that more than half of its components are ice. Enceladus is the lowest density of Saturn's moons. Its albedo is 100%. Although there are craters and rugged Yuan Ye, it is basically flat. Edit this paragraph of Titan.
The main component of Titan is pure water ice. It has a diameter of 1060 km and orbits Saturn at a distance of 294660 km. Titan has two noteworthy features: first, there is a big crack which is equivalent to three-quarters of the circumference of the whole planet, accounting for 5% to 10% of the whole surface. It is speculated that the big crack is caused by the freezing and expansion of water inside the satellite; First, there is a 400-kilometer-diameter crater with a huge central peak. Titan's diameter is 1 120 km, and it orbits Saturn in a nearly circular orbit with an average distance of 377,400km. It orbits once every 66 hours, which is exactly twice that of Enceladus period of revolution. It is estimated that it is caused by the tidal heat of Enceladus. Because of tidal friction, Titan's rotation and revolution are synchronous, and it always faces Saturn in the same direction. Edit this paragraph of Enceladus.
The surface brightness of Enceladus varies greatly, and the first half facing the orbital direction is usually brighter than the second half. But on average, Titan has a high albedo. According to this guess, its surface is made up of a lot of ice. The density of satellite is 1.4 times that of water, and it is estimated to be composed of about 40% rocks and 60% ice. Obviously, there have been a lot of ice melting and crustal surface reconstruction activities on this satellite, so there are fewer craters on the surface than other Saturn satellites. Most craters are on the bright side of the track. The darker back half is separated by many bright lines, forming a network structure. Some of them are linear grooves and ridges. These bright lines are explained to be probably caused by the re-condensation of volatile substances appearing in the linear cracks inside Titan. Although there are signs of a big collision near the center of the network structure on the back of Titan, it is still unclear why there is such obvious asymmetry on the surface of Titan. Edit Rhea's passage
With a diameter of 1530 km, Rhea orbits Saturn in a nearly circular orbit with an average distance of 527040 km. The density is 1.3 times that of water, so it is generally considered to be mainly composed of ice. Infrared spectrum also shows that its surface is mainly composed of frost. The surface albedo of Rhea is high, but there are great differences in different regions. Like most Saturn's moons, Rhea's rotation and revolution are synchronous, so it always faces Saturn in the same direction. Like Rhea, the first half of Rhea's orbit is bright and full of craters, and the second half is dark, with only some bright lines, a few craters and some signs of surface reconstruction. Although there is more ice on the surface of Rhea than stones, the rich side of craters is very similar to those cratered highlands on Mercury and the Moon. In Saturn's system, Rhea has the most craters on its surface. At extremely low temperature, ice and rock obviously have similar mechanical properties. On the less side of the crater, you can see bright, linear or
Saturn's moons
Disconnection, which may be the result of large-scale surface reconstruction and a large number of volatile substances (such as water or methane gas) emerging from the cracks. The bright spot of the crater may also be caused by this situation. Edit this passage of Titan.
The distance from Saturn's orbit is 1, 2 1, 830 km, the satellite diameter is 5 150 km, and the satellite mass is 1.35e23 kg. Titan was discovered by Huygens in 1655. During this period, people have always thought that Titan is the largest satellite in the solar system and named it Titan (in Greek mythology, Titan is a giant family). One of the missions of Voyager 1 is to study Titan. Voyager 1 flies at an altitude of 4000 kilometers from its surface. Although its camera can't penetrate Titan's atmosphere, it still takes some precious photos for people. People know more about it in a few minutes than in the previous 300 years. Titan is almost half ice and half rock. It may be divided into many layers, with a rock core with a diameter of 3400 kilometers, surrounded by many layers composed of various ice crystals. It may still be hot inside. Its density is so great that its own gravity pushes it toward the center. Titan's atmosphere is very noteworthy. On the surface, its pressure is greater than 150 kPa (the earth's atmospheric pressure is101kpa; 50% higher than the earth). It is mainly composed of molecular nitrogen (just like on earth), with only 6% argon and some percentage methane. Interestingly, there are more than a dozen other organic compounds (such as ethane, hydrocyanic acid and carbon dioxide). These organic substances are formed like methane. They were destroyed by sunlight in Titan's upper atmosphere. The result is similar to the smoke found over big cities, but it is thicker. In many ways, this is similar to the early conditions in the history of the earth when life began to appear. Edit this paragraph of Titan.
Titan is a smaller satellite of Saturn. It orbits Saturn once every 23.3 days, with a distance of 0/481000 km, between the orbits of Titan and Partos. It is an irregular celestial body with a size of 4 10 km ×260 km ×22 km. Its albedo is very high (30%), which indicates that its surface is covered with frost. Edit this passage by Partos.
Partos is a peripheral satellite in Saturn's satellite system, which is unusual because of its appearance. French astronomer Cassini discovered it in 167 1 year. Partos orbits Saturn in 79.33 Earth Days, with a distance of 356 1 1,000 km. The radius is about 730 kilometers, and the overall density is 1. 16. A solid celestial body with such a small density can only be mainly composed of ice. It is observed that the rotation period of Partos is equal to its period of revolution, which is the same as that of the moon. Tides will also appear on the solid surface of Partos due to the gravity of other nearby planets. Therefore, one side of Partos always faces forward in orbital motion, while the other side always follows forward. The front hemisphere only reflects a small part of the sunlight that shines on it, which makes it particularly dark, while the back hemisphere is a good reflector, which is 10 times brighter than the front hemisphere. Of all the celestial bodies in the solar system, it is the one with the greatest brightness change. Voyager found craters in the front hemisphere, but not in the back hemisphere. In the surface material of the bright hemisphere, there is definitely water ice, but there is not a mixture of methane and other ice. The surface dark matter facing the front hemisphere is considered as an organic molecular compound, which may come from Titan, Saturn's outermost satellite, or may be formed in situ by solar ultraviolet radiation of methane in ice. In the latter mode, the rapid evaporation of methane ice and the bombardment of micrometeorite caused the ballistic transfer of surface materials from the front hemisphere to the back hemisphere, which may explain the brightness asymmetry between the front hemisphere and the back hemisphere. The characteristic of Partos is that half of it is six times brighter than the other half; The dark half is like black paint, and the bright half is like snow. The reason is still unknown.
The newly discovered relationship between Saturn's rings and Partos.
Recently (June 8, 2009 10 news), NASA scientists found an "invisible" huge halo around Saturn (pictured), which is composed of ice and dust particles and can accommodate 10 billion Earth. The discovery of rings may help to explain an ancient and mysterious question about Partos, another satellite of Saturn. The newly discovered corona rotates in an orbit opposite to that of Iraq and Partos. Scientists speculate that the dust in the halo splashed on the surface of Partos, forming a black area. "For a long time, aerospace scholars have always believed that there is some connection between Phoebe and the black substance on the surface of Partos, and the newly discovered halo provides convincing evidence for this." Douglas Hamilton, one of the discoverers of the new aura and an expert at the University of Maryland, said. Edit this paragraph of Enceladus.
Titan is about 220 kilometers in diameter, and the average distance from Saturn is about 12952000. It is the farthest satellite from Saturn. The eccentricity of the orbit is very large, and the inclination angle with Saturn's torus is also very large. It is an ordinary satellite, but it is retrograde. Enceladus is the only retrograde satellite from Enceladus to Enceladus 10, and its rotation direction around Saturn is opposite to Saturn's rotation direction around the sun. Therefore, Titan may be a captured asteroid-like object, not Saturn's original satellite. Edit this paragraph of Enceladus.
Enceladus is a small satellite with irregular shape. It and Enceladus 1 1 orbit Saturn in two orbits, only 50 kilometers away. When you are close, you will switch tracks, with the outer side turning inward and the inner side turning outward. This happens every four years. This is a rare situation at present, and the Cassini probe will find out the reason when it reaches Saturn. Because the surface of Enceladus has been hit many times, people think that its surface has a history of billions of years. Edit other small satellites in this paragraph.
Epimetheus
Enceladus XI and Enceladus X are "binary stars". There are many craters (craters) with a diameter of more than 30 kilometers on its surface, as well as large and small ravines. It is generally believed that Titan XI must be very old.
Helene (Helen's variant) (F.)
It was discovered in 1980 by Lax and Lekachu of the ground observatory. Titan is located in front of Lagrange of Titan, so it is sometimes called Titan B.
Telesto
It was discovered by Smith, Reitzma, Larsen and Fontaine through ground observation in 1980. Telesto is located in front of Titan's Lagrangian point.
Enceladus XIV
Titan 14 is at the lagrange point behind Titan. Both Enceladus XIV and Enceladus XIII belong to small satellites of the solar system. Note: The photos of Enceladus 14 in Voyager CD-ROM are marked with the wrong number; They are actually pictures of Titan. Similarly, the photo marked Titan XIII is actually Titan XVII.
Rhea XV
It was found in the photos sent back by R. Terrile from Voyager in 1980. Rhea 15 seems to be a shepherd satellite with a ring.
Prometheus
Titan is the shepherd satellite in the F ring. Titan has many mountains and valleys, and some craters with a diameter of about 20 kilometers. But it seems that it has fewer craters than its neighboring satellites (Enceladus 17, Enceladus 10 and Enceladus1/0/). Judging from their low density and relatively high albedo, Titan XVI, Titan, Titan and Titan XI may be porous and icy objects. (Note: There are still many uncertainties in these values. ) According to the observation of Saturn's intersecting line in June 1995, it is found that the position of Titan calculated from the data of Voyager 198 1 has declined.
Saturn's moons
After 20 degrees, this is not enough to be explained by observation error. Maybe Titan's orbit has changed recently because of its meeting with the F ring, or he may have a small partner to share this orbit with it.
Pandora
This satellite was discovered by Collins and his companions from Voyager's photos in 1980. Enceladus 17 is a shepherd satellite outside the F ring. From the picture on the right, we can see Titan's 17 and a part of the obscure F ring, Titan's 16 and A ring. The crater on this satellite is larger than that on nearby Titan 16, which has at least two large craters with a diameter of about 30 kilometers. But it has no long mountains and canyons.
Titan 18
Titan 18 is located in enke ditch of Saturn's ring belt a. Wave patterns produced by small satellites near the halo. Before Enceladus was discovered, the study of this pattern on the edge of Saturn's A ring predicted the position of a small satellite. Titan was discovered by revisiting the predicted position in the photos taken by Voyager 10 years ago. There may be more moons to be discovered in Saturn's rings. Edit the other minisatellites in this paragraph.
Besides Enceladus to Enceladus 18, Saturn has thirty-four named microsatellites and eight unnamed microsatellites. They are: Enceladus No.19 Ymir, Enceladus No.19 Paaliaq, Enceladus No.22 Tarvos, Enceladus No.12 Liraq, Enceladus No.13 Suttungr, Enceladus No.14 Kiviuq, Enceladus No.15 Mundilfari, Enceladus No.27 Albiorix, Enceladus No.17 Skathi, Enceladus No.28 Erriapus and Enceladus No.19.
Saturn's moons
Siarnaq，Titan Thrymr，Titan 1 1 Narvi，Titan 12 Methone，Titan 13 Pallene，Titan 14 poly duces， Titan 15 Daphnis, Titan 16 egil, Titan 17 bebionn, Titan 18 Bergelmir, Titan 19 Bestla, Enceladus Farbauti, Enceladus1/Fenrir, Enceladus 12 forn jot, Enceladus 13 Hati, Enceladus 14 Hyrrokkin, Enceladus 15 Kari, Enceladus 16 Logue, Enceladus 17 Skoll, Enceladus 18 Stell, Enceladus 19 Anthe, Enceladus 10.