Seven papers jointly report on the latest discovery of "Dawn" that
　　Ceresus may still have salty liquid

　　Science and Technology Daily, Beijing, August 10 (Reporter Zhang Mengran) "Dawn" is the first man-made device to detect the asteroid belt and visit dwarf planets, ushering in a new era of human space exploration. On the 10th, the British journals "Nature·Astronomy", "Nature·Earth Science" and "Nature·Communication" published 7 papers at the same time. The United States, Germany, Italy and other multinational teams reported the second extension of the "Dawn" mission to Ceres Observation. The results show that Ceres is an ocean world, and geological movements have been active in the recent history. These studies provide important insights for understanding the history and formation of dwarf planets.

　　Ceres is the only dwarf planet in the solar system located in the asteroid belt. The NASA "Dawn" probe flew around Ceres from 2015 to 2018 until it ran out of fuel. In the final orbiting phase, the probe is only 35 kilometers from the surface of Ceres.

　　In the first study, the California Institute of Technology team analyzed the high-resolution gravitational data and images sent back by the Dawn. The main observation point of the probe is the 20 million-year-old Okato Crater, where the probe has discovered bright reflections from brine deposits inside the planet. This time, the "Dawn" discovered a large brine reservoir deep at the bottom of the Okato crater. The team believes that the reservoir may have been affected by the force that formed the crater and moved, causing these bright salt deposits to appear on the planet's surface.

　　In another study, the Italian National Institute of Astrophysics team reported that hydrated chloride salts exist in the center of the largest bright area in the center of the Okato crater. Due to the rapid dehydration of these salts, the team believes that the brine may still be gushing out, which means that there may still be saline liquid inside Ceres.

　　In other papers, the Caltech team also analyzed the crustal composition of Ceres; the team of the Max Planck Institute for Solar System Research in Germany pointed out that Ceres had started a period of active ice volcanoes about 9 million years ago, and has not been until recently. End; research by the Georgia Institute of Technology team in the United States has shown that the hills of Okato Crater may have formed when the impact caused water to freeze. This shows that not only Earth and Mars, but Ceres has also recently experienced active freezing hydrology in geology. phenomenon.

　　In the other two studies, scientists also found that the water- and salt-rich mud-like impact lava on Ceres is different from that on Mars and is not as large as Mars; and the various bright deposits in the Okato Crater may have different sources.

Editor-in-chief

　　Previous studies have shown that Ceres is a complex and vibrant world, with a large amount of liquid water accumulated in the past. The seven papers published in this journal once again confirmed this view. The ability to make such a detailed study of Ceres benefited from the "Dawn" project. Before, humans could only use a telescope to explore the true face of Ceres, but it was really vague. The probe "Dawn" flew around Ceres at close range, and it allowed humans to know this "old friend" further. The body of Ceres hides the mystery of the formation and evolution of the solar system. Now, the mission of "Dawn" has been completed. Using the large amount of data returned by it, various research results are also being released.