A reconstructed perspective of Juling Crater, where a patch of water ice is slowly growing on the north wall.
(IAPS – INAF (Italy)
Growing patches of ice and minerals with liquid water, it is found that the dwarf planet Ceres is still in development.
Researchers are studying the warmer regions of Ceres — the largest object in the asteroid belt between Mars and Jupiter have noticed that there is a patch of ice has grown in the time. In addition, there is a separate team found carbon-rich minerals on Ceres’ surface that is not long . Together, the new discoveries suggest that the water is still a powerful presence on the small world.
With the help of NASA’s Dawn spacecraft, the researchers studied the surface of the dwarf planet. The first team, led by Andrea Raponi, of the Italian National Institute for Astrophysics (INAF), has found a growing patch of ice on Juling Crater, found in the midlatitudes. They suspect that the water from the crater floor is condensation on the wall, causing a piece of ice to grow larger. [7 Strange Facts About Dwarf Planet Ceres]
The second team, led by Filippo Giacomo Carrozzo, also of INAF, the carbon-rich minerals on the dwarf planet and assigned various regions in detail, revealing changes in the soil, which they suspect are bound to the carbonates. The water-rich, hydrated minerals, suggesting that the water has risen to the surface and boiled off, leaving the carbonates behind to reveal its presence.
“The same process may be at work in the crater of Juling, providing a complement of water under the ground that sublimes and in part condenses on the cold wall,” said Raponi Space.com by e-mail.
“The two works show that water is currently available on the surface of Ceres and produces geological and mineralogical changes at the surface,” he said.
Fingerprints of water
Ceres is classified as a dwarf planet and an asteroid. When the Dawn spacecraft will arrive at Ceres in 2015, the find of an almost featureless world with a rocky surface. A single mountain, Ahuna Mons, was on the surface. Bright spots within craters were the only color variations on the otherwise dull, grey world.
As scientists researched the dwarf planet, they find tips that Ahuna Mons was not only a mountain, but a cryovolcano — also known as an ice volcano. Thick water ice rose to the surface in the past, flooding the plains with ice lava. The researchers found hints that other icy cryovolcanoes can studded Ceres in the past for slowly easing back into the landscape, their heights, spread out over the landscape.
Eventually, the Dawn revealed that the 130 bright patches of sodium carbonate, salts forms on the Earth, as water evaporates from a body of water such as a lake, or in hot springs. It is difficult for water to stick around on Ceres’ surface. The lack of an atmosphere on the small world means that sunlight is the liquid to boil away immediately, leaving behind the rest of the minerals on the surface — such as carbonates.
“Carbonates are minerals that are very important because they give us information about the presence of water on Ceres in the past and in the present,” said Carrozzo Space.com by e-mail.
In addition, they “are some of the most interesting minerals, researchers can observe on the planetary surface,” he said. “They are the most important minerals for the understanding of the Ceres environment, because they are indicators of neutral to alkaline water.”
Carrozzo, the team mapped the entire surface of Ceres with Dawn’s Visible and Infrared Spectrometer to search for carbonates. Their results showed that some of the regions require different forms of the sodium carbonate than Dawn had previously identified. The new traces of sodium carbonate are more likely to carry water within their structure than before, if their signals are a good match to minerals such as trona and thermonatrite.
“Trona is a sodium carbonate with two water molecules in the structure,” Carrozzo said. “If we look at a planetary surface, we are sure that water played a role in the formation.”
Dawn’s results revealed that most of the sites rich in sodium carbonate are found in the younger areas along the domes and mounds, as well as in the material ejected by the impact formed craters. Although it is possible that the carbonates form in the heat of the impact, the researchers in favor of the idea that the brine below the surface welled up to ooze through the crust. Such cryovolcanism requires that Ceres’ internal temperatures remain warm enough for water to freeze completely, remaining instead as a cryomagma that is rich in sodium carbonate, Carrozzo said.
In addition to hinting at the current activity on Ceres, the team of the results suggest that the dwarf planet formed further into the solar system than the asteroid belt, and the previous discoveries of the ammonia-rich clay on the dwarf planet to support that idea, Carrozzo said.
“Sodium carbonate is one of the compounds found in the plumes of Enceladus, a moon of Saturn,” he added. “This finding reinforces the idea that Ceres formed in the outer solar system.”
Percolating the water
While Carrozzo is the focus of research on the mapping of the entire surface of Ceres, Raponi, the study focuses on a specific crater. (Because they are members of the Dawn team, many of the researchers, including Carrozzo and Raponi, the authors on both papers.)
Although the water ice is to be found in the shadow of the craters, most of these craters are in near Ceres’ north pole. Juling Crater, however, is located in the dwarf planet’s midlatitudes, where the sun is higher over head, and shadows are harder to maintain. The northern wall of the 1.6 km deep (2.5-kilometer) crater is almost always shrouded in shadows. It is lit by the reflection of the crater, Raponi said.
Juling Crater has a patch of ice on the northern wall. Using Dawn’s Visible and Infrared Mapping Spectrometer, Raponi and her colleagues were able to watch the ice grow from 3.6 square miles to 5.5 square miles (9.3 square miles to 14.2 square miles) over a period of six months.
There are two ways to order the visible ice piece can grow, the researchers said. The first possibility is that the ice could already exist under the superficial exterior of previous studies have shown that the water ice includes many of the dwarf planet’s surface and then slides along the side of the crater could slowly reveal material, Raponi said. In that case, the self ice cream would not be greater, but rather should be discovered slowly.
However, the team is preferably water vapour. Geological formation similar to the Earth’s glaciers cross the bottom of the crater, with a large a on the foot of the northern wall. The rock may be the source of the ice, such as the crater of the wall, and water molecules originating from just below crater.
“We have proposed that liquid water is percolating under the surface and then freezing to the surface of the cold wall, when exposed,” Raponi said.
The process could be a source of heat, that is at this moment unknown, but he said that other indications of water-rich minerals, such as which is characterized by Carrozzo and colleagues with similar processes in Ceres.
“The increasing solar input, as a result of the changing season and the decreasing of the distance of Ceres from the sun, would be the driving force of the sublimation of water from the surface of the floor that are a part deposited on the surface of the shadow wall,” Raponi said.
He pointed out that Carrozzo the research suggested a source of water-rich material rises from beneath the surface as the source of hydrated carbonates. A similar process can complement the rock-glacier in the crater, and provides a source of water that helps to grow in the icy region.
The new research shows that Ceres is not an inert ball of rock, but rather a constantly evolving world of the icy.
“In general, the two works show that water is currently available on the surface of Ceres, and produces geological and mineralogical changes at the surface,” he said.
Both newspapers were published yesterday (14 March) in the journal Science Progress, and can be seen here, here and here.
Originally published on Space.com.