A lot of small objects surround our Sun inside Main asteroid belt located between the orbits of Mars and Jupiter, and these tiny rocky and metal "worldlets" are lingering remnants of the primeval era of the creation of planets, when our solar system was formed about 4.56 billion years ago. Astronomers have known for decades that Ceres is the largest asteroid living in Main asteroid belt but in 2006, the International Astronomical Union reclassified Ceres as dwarf planet because of its large size. Ceres kept her secrets well, still! In 2015, planetary scientists using data from NASA Dawn Spaceship, published two new studies that appear in the online edition of the journal on December 9, 2015 Nature. The two documents cited the long-awaited observations related to the mysterious nature of the strange bright spots found throughout dwarf planet and also raise new questions about how Ceres was formed.
In the first study, planetary scientists believe that strange, mysterious bright spots scattered across the surface of Ceres are made up of salt. The second study points to the discovery of ammonia rich clays, which gives some painful clues about how Ceres appeared.
Launched in September 2007 Dawn Spatial Probe the mission is to study two of the three largest inhabitants Main asteroid belt Vesta and Ceres. dawn is the first spacecraft to orbit two extraterrestrial objects, the first to visit dwarf planet, and first visited Vesta or Ceres. dawn reached Ceres in March 2015.
July 16, 2011 dawn entered the orbit of Vesta, completing the 14-month research mission before being sent to Ceres at the end of 2012. dawn went into orbit around Ceres March 6, 2015, and is expected to remain in orbit after completing its mission.
dawn Mission managed by nasa Jet Propulsion Laboratory (JPL) in Pasadena, California. Spacecraft are also sports components, which were provided by European partners from Italy, Germany and the Netherlands. This is NASA's first research mission in the use of the ion engine, which allowed it to enter and then leave the orbit of more than one celestial body. Early target missions like two Voyagers which were launched back in 1977, they could only make flybies.
dawn The goal is to study the conditions and processes that built our original Solar System, observing in great detail Ceres and West, the two largest inhabitants Main asteroid belt lucky they stayed in the same place from the time of their ancient formation. The most important question that dawn addresses are the role of water and size in determining the evolution of the planets of the solar system.
There is an invisible separation between the small, rocky, inner terrestrial planets (Mercury, Venus, Earth and Mars) and the giant gas planets that remain further (Jupiter, Saturn, Uranus and Neptune). Main asteroid belt located in the region of separation between Mars, the outermost rocky planet, and Jupiter, the most intimate giant, gaseous world. About 4.5 billion years ago, water and other volatile substances evaporated from the inner, warm and well-lit domain of the Earth's planets, turning them into small, rocky and very dry worlds. Only in remote areas, far from the light and heat of our Sun, do these volatile substances survive. These substances exist to this day in a quarter of the gas planets that inhabit the outer borders, as well as in their large population of ice moons. Even the water that still exists on Earth today is a later arrival from this reliably dark, distant and cold region that exists in the eternal cold twilight. But where is the so-called Ice line today and where was it in the past? Where could water ice survive in our solar system?
dawn looking for answers to these important questions in Main asteroid belt - a region populated by countless asteroids, some large, some small. At the beginning of 2015, at the stage of approaching Ceres, unusual bright spots were first observed on its surface, tickling the imagination of both astronomers and non-professionals.
Was it exposed by ice? Or salt bestowed bright spots with their strange high reflectivity? “At present, we are likely to see remnants of the evaporation process, demonstrating different stages in different places. Andreas Natus on December 9, 2015 Press release of the Max Planck Institute (MPG). Dr. Natus, who Institute for Solar System Research. Max Planck in Göttingen, Germany, is the lead researcher for a group of cameras and the first author of one of two new studies, published in a journal issue of December 9, 2015 Nature , This study reports on the character of Ceres & bright spots.
Our solar system Main asteroid belt is home to countless mostly rocky pieces that are similar to those that went into building the four inner planets. Similarly, in addition, there is a distance belt of a huge number of ice nuclei of comets, similar to those that merge together to form a quarter of the giant gas planets. This very distant belt of cometary bodies is called Kuiper belt, and it is outside the orbit of the outermost planet of our solar system, the dark blue ice giant Neptune. In addition, there are two other distant regions of cometary nuclei - Scattered disk and Oort Cloud. Oort Cloud is an highly remote, and it is believed that it forms a shell surrounding our entire solar system , which extends almost halfway up Proxima Centauri - the nearest star is outside our own sun.
Both asteroids and comets are relics. planetesimals - the original building blocks of our planets in the solar system. A long time ago, when our Sun and its family of objects were still forming, planetesimals both rocky and icy, exploded into each other, merging together - and sometimes breaking each other up into fragments. Asteroids, such as those that inhabit Main asteroid belt are remnants of rocky planetesimals who built the inner planets, while the comets are covered with icy planetesimals which entered the construction of four external gas planetary giants.
Ceres occupies one third of the total mass Main asteroid belt and its spectral characteristics indicate that it consists of the same material as water-rich. carbon chondrites. Carbon chondrites are a group of chondritic meteorites, which include eight known groups. These include some of the most primitive known meteorites.
Vesta, the lesser of two inhabitants Asteroid belt visited Dawn, is poor water and reminds achondrite asteroid , Vesta combines a tenth of the mass of all Main asteroid belt and it has undergone significant heat and differentiation. It also shows signs of a metallic core, basalt flows, such as the Earth and the Moon of Mars.
Both Ceres and Vesta are believed to have formed very early in the history of our solar system, and there, before keeping a fabulous tale about what happened a long time ago, starting with the formation of the internal terrestrial planets ,
Ceres & # 39; Mysterious bright spots
Dr. Natus and his team using images from Don & # 39; s that these bright spots are salt-rich areas that were left behind when water ice was sublimated in the past.
“The global character of the bright spots of Ceres suggests that this world has an underground layer that contains salty water ice,” said Dr. Nuthes on December 9, 2015. Press release JPL.
The surface of Ceres is dotted with more than 130 bright areas, and most of them are associated with impact craters. Dr. Natus and his colleagues write in their research work that this is consistent with the type of magnesium sulfate Hexahydrad. Other form Hexahydrad familiar on Earth as Epsom salt.
According to the researcher, the Ceres surface has an average diameter of 584 miles, and for the most part it is very dark and similar in brightness to fresh, recently dispersed asphalt. Bright spots that are scattered throughout Ceres surface shows a wide range of brightness, with bright spots reflecting about 50 percent of the sunlight emitted over the area. However, in Ceres there was no unequivocal detection of water ice, and higher resolution images are needed to answer this very important question.
Interior Crater on the surface of this dwarf planet active, and when the sun shines into the crater's mysterious heart, a thin, thin haze floats above its bright spot. This can be seen in the images taken by the camera on board. dawn This thin, thin haze suggests that water ice can be secreted near the surface. Bright spots in Crater are believed to contain magnesium sulfates which are a class of mineral salts. A large number of other bright spots on Ceres # the surface is now easily made up entirely of dried mineral salts. New results show that since the birth of our solar system, water ice has survived not only in the most remote outer boundaries, away from the heat and luminous light of our Sun, but also in relatively close The main asteroid belt.
Inner area Crater Shows the brightest material on Ceres. Crater itself is about 60 miles in diameter, and its central pit is covered with this bright material. The bright area in the crater is about 6 miles wide and 0.3 miles deep. Strips of dark material, which are considered fractures, cut through this hole. Lingering remains of a central peak, which could be up to 0.3 miles in height, can also be detected.
Occator it appears to be one of the youngest elements on the surface of Ceres, and it displays a sharp edge and walls, as well as a number of terraces and sediments left by landslides. dawn mission astronomers estimate Occator & # 39; s The age of "only" is approximately 78 million years.
The authors of the study write in the journal Nature, what some observations Occator show that a thin, diffuse haze near the surface of the crater fills its entire floor. A thin haze appears in the day cycle, when rays of sunlight stream down to the crater floor. It is possible that ice evaporates from there and that this water vapor captures tiny dust particles and pieces of residual ice. This process has a transitory resemblance to the degassing of comets, but on Ceres it is proceeding at a lazy pace and without comet eruptions. Future data and analysis can test this theory and show some clues related to the process causing this activity.
Findings about the existence of ice on Ceres have been known for some time. For example, the density dwarf planet too low to contain pure rocky metal. In early 2014, astronomers on European Space Agency (ESA) announced that they had witnessed the presence of water vapor near Ceres, using Herschel Space Observatory. Unlike the last measurements of 2015, the gas was not spatially resolved, but its presence hinted at an absorption line in the light spectrum.
" dawn the research team is still discussing these results and analyzing the data to better understand what is happening on Occator - commented Dr. Chris Russell on December 9, 2015 Press release JPL. Dr. Russell is the principal investigator. dawn mission based at the University of California, Los Angeles (UCLA).
The second bright feature on Ceres # surfaces, Oxo crater ("Function A" in the study) is also relatively young, and may also contain ice. “The most plausible interpretation of our results is that there is a mixture of ice and salt under at least some parts of the surface of Ceres,” Dr. Nathes noted on December 9, 2015 Press release MPG. This material could be exposed as a result of impacts created by medium-sized asteroids. Then the ice slowly evaporates, while only salts and phyllosilicates are left to tell the story.
“Our results show that subsurface ice could also survive in the asteroid belt, which is relatively close to the Sun. The rocky surface layer protects it from the influence of the Sun, ”continued Dr. Natus. The distance between our Sun and Ceres is only about 414 million kilometers. Our running solar system, Jupiter, which is surrounded by icy moons, flies out of the water, almost twice as far away; and comets, which are heavily loaded with water, spend most of their time even further in our solar systems with dark, frigid outer limits.
It is possible that Ceres is not the only ice reservoir that is close to the smooth warmth and fiery brilliance of our Star. Spectral observations of a large asteroid Pallas, which surrounds our Sun at a distance comparable to the distance of Ceres, show that the surfaces of both inhabitants Main asteroid belt possess similar compositions.
Ammonia-rich clay
Per second Nature documents members dawn The research team examined the composition of Ceres and found evidence of the existence of ammonia-rich clays. Astronomers used data from a visible and infrared mapping spectrometer, a device that examines how different wavelengths of light are reflected by the surface, which allows us to identify minerals.
Ammonia ice alone evaporated at Ceres. This is due to the fact that dwarf planet too toasted to provide a suitable environment for ammonia to remain icy. However, ammonia molecules can be stable if chemically bound to other minerals.
The presence of ammoniated compounds suggests the intriguing possibility that Ceres was not born in Main asteroid belt but instead, the wanderer from whom he formed in the outer regions of our solar system. An alternative idea is that Ceres was born close to its current position, but included materials that migrated from our outer boundaries of the solar system — close to the orbit of Neptune, where nitrogen ice is thermally stable.
“The presence of ammonia-containing species suggests that Ceres is composed of material injected in an environment where ammonia and nitrogen were abundant. Maria Cristina de Sanctis on December 9, 2015 Press release JPL. Dr. de Sanctis is the lead author of the study based at the National Institute of Astrophysics in Rome, Italy.
When a group of astronomers compared the spectrum of reflected light emanating from Ceres to meteorites, they found some intriguing similarities. First, they studied the spectra or chemical fingerprints carbon chondrites which are carbon-rich meteorites, which are considered analogues of Ceres. However, they turned out to be inconsistent with coincidences at all wavelengths selected by the spectrometer. Most importantly, there are various absorption bands corresponding to mixtures containing ammonia minerals associated with wavelength, which could not be seen with telescopes on Earth.
Astronomers have noted another difference. carbon chondrites have a volumetric water content of 15 to 20 percent, whereas Ceres & reg; content is up to 30 percent.
Dr. De Sanctis celebrated at 9 December 2015. JPL Press Release that "Ceres may have saved more volatile than these meteorites, or it could increase the water from volatile substances."
