The asteroid, the types and names of the asteroids, opening, distinction from other objects.
Asteroid – one of the types of bodies present in the Solar system. The sizes of the asteroids are quite large, from 30 meters in diameter. Body smaller added to meteoroids.
The concept of the asteroid. The shapes and sizes of asteroids
Classification of asteroids. Classes of asteroids: class C, class S, class M.
What the asteroid was discovered first? The discovery of asteroids
Well-known large asteroids in the solar system: Ceres, Vesta, Pallas, Gigeya, Interamnia, Europa, Davida, Sylvia, Hector, Euphrosynos
Asteroids approaching to the Earth
Unlike the asteroid from a meteorite, comets and dwarf planets
Where are the asteroids? The main asteroid belt, the Kuiper belt, the scattered disk, the Oort cloud, orbit Saturn
The concept of an asteroid:
The solar system consists not only of the eight planets, but also of many other solids, called the small. Comets, dwarf planets, centaurs, damocloid and the other composed of the different chemical elements. Some of them have their own orbits, which rotate around the Sun, others are in outer space in the “free flight”. Special attention researchers pay to the asteroids – bodies that, until recently, equated to the planets, not having an atmosphere, but often wielding companions. What caused this interest and what is their fundamental difference from other space bodies?
Asteroid – one of the types of bodies present in the Solar system. Its name comes from combining two Greek words meaning “star” and “look, appearance” and literally means “like a star”. This is easily seen, if you look at it through a telescope: the body is bright, shining, uneven, whereas the planets represent the Matt disk.
The sizes of asteroids are different, most of them quite large, from 30 meters in diameter (body smaller added to meteoroid), so for a long time, until 2006, they were considered small planets. Today, according to the classification of the International astronomical Union asteroids are small celestial bodies of the Solar system which:
– have their own orbit;
– different irregular geometric shape;
– do not contain the atmosphere;
– you can have companions.
The shapes and sizes of asteroids:
In the definition of an asteroid is indicated as a celestial body of irregular shape, and it was one of the reasons for excluding them from the number of planets, but the largest objects still like the ball – how can this be explained?
Scientists believe that the formation of the Solar system asteroids were of considerable size and of appropriate shape, but in their “life” they encountered other space objects, subjected to explosions and decay. So, to maintain its original state managed only a few. Heavenly the bodies of small dimensions and reduced gravity, which does not allow to crush and stamp of heavy matter, giving the surface the usual form of a ball. Therefore, the asteroids exist in the form of aggregates, which include several blocks. They are held between the force of gravity, which also allows them to firmly unite and blend together. All these parameters and form the desired shape, which is considered to be wrong.
Another important criterion is size. So, scientists have determined that objects of this type are considered to be of the body, exceeding 30 meters in diameter, but how to accurately measure the size of the Earth? This applies to several methods.
First, measure the diameter of a celestial body scientists have decided in the beginning of the XIX century, using a thread micrometer. This device, combine with a telescope, which is the two fine thread or wire, the distance between them varies due to the screw mechanism of high precision. The disadvantage of this technique was made by the fact that when using different telescopes produced different results and sometimes the difference in the indices exceeded significantly.
The development of science and technology has allowed to invent other ways of determining sizes, the most popular of which was the transit method, and polarimetry.
The first is that all celestial bodies move and when the asteroid is passing on the background of distant stars, she’s covering for him. If you know the distance to the asteroid, it is sufficient to measure the duration of reduce the radiance of the stars to get a very exact size of the desired celestial body. The disadvantage of the method – comparative accuracy of the calculations inherent only to large objects.
Based on polarimetry are the brightness of the asteroid. So, the larger its size is, the more sunlight is able to reflect the surface. Note, however, that the reflectivity depend on the chemical elements prevailing in the composition: the presence of metals will make the object more vivid even at low settings. However, the reflectivity (albedo), scientists can easily determine with the aid of infrared radiators, based on the principle: the less light reflects the body, the stronger it absorbs and is heated, and, consequently, more thermal energy is released.
Polarimetry is used for determining the shape of a celestial body. The method allows to capture the differences in luster, changing during the rotation of the asteroid around its orbit. These observations allow to study the period of rotation and the structure of the surface, to discover her large projections and depressions.
In addition, use of such methods:
radar. Based on the data comparison probes and eholokatsii, is one of the most accurate methods. Allows to study the speed and trajectory of the movement, characteristics of the surface, the distance to the object, etc.;
– speckle interferometry. The method consists in the detailed study of the grain structure of the image of a celestial body.
Classification of asteroids. Classes of asteroids:
Like the planet, they have significant differences from each other. The combination of these qualities has allowed to divide them into appropriate groups and classes. First and foremost take into account the peculiarities of the orbits and visible spectrum of solar rays, which reflect from the surface.
The first classification divided the asteroids into 3 main groups, but as study of celestial bodies, the list was expanded and continues to grow. The first division is taken as the basis, based on the key chemical element, which consists of a small body. This:
class C – carbon (more than 75% of all registered bodies);
class S – silicate (about 17%);
class M – metals (all others).
The class is the main class of bodies, which are objects of the dark spectrum of the carbon nature. According to calculations of scientists, it includes three quarters of all known asteroids, but it is not excluded that their quantity much more. This is due to the fact that due to the weak ability to reflect the sun’s rays are difficult to detect, so the counting objects to the small size of this group to not yet possible.
The range of carbonaceous objects close to the stone chondrite meteorites. The latter contain in its composition of chemical elements of the nebula, which, at the time, allowed to form the Sun, but exclude the presence of volatile substances – helium, hydrogen and others. In this regard, the probability of availability of these mineral resources is large.
To detect the asteroids With class is very difficult because of their darkness. So, one of the most famous representatives of this class – Bamberg, fixed extremely powerful telescopes due to its considerably eccentric orbit, but only for a short period of time. The largest asteroid class is considered Gigeya.
Class S – second number of objects of a class that includes objects with a primary silicon structure, for which even has received the name of stone. The brightness of the spectrum (albedo) of these bodies is average, and their main chemical substances are silicates of magnesium and iron (stony minerals).
The largest asteroids are:
These objects are easy to observe from the Ground using conventional binoculars due to their brightness.
A special prominence was also given to:
– Vesta is the brightest object in the group;
– Itokawa – the first body, whose surface has been explored by researchers and second, where was a place for the landing of the spacecraft.
The M-class the third class, whose study is of great complexity. Among all the celestial bodies of this type they are the brightest due to the content of a significant amount of the metals of Nickel and iron, but this composition is not inherent to each of them. According to scientists, these asteroids are remnants of the cores with a high content of ore larger their group, the destruction which occurred at the stage of formation of the Solar system. The most significant value of the class representative is the Psyche.
The separation of asteroids into classes continues, because in many groups there are objects that are not completely or only a small part of meet the established criteria, but the study of them difficult. So, calliope, classified as M-class has a very low density, so physically can not consist of ore, but at the same time, its albedo directly indicates the presence of metals. Similar situation with the asteroid of the same class Lutecia that allows scientists to suggest the presence of hydrated metals and rocky minerals.
What the asteroid was discovered first?
The official opening date of the asteroid is considered to be January 1, 1801. Scientists and physicists of that time assumed that the distance between the orbits of Jupiter and Mars is very large, which means that in this range may be another, as yet unknown, planet. Long observation has allowed to find several large asteroids, but because they had an irregular shape, were relatively small and were not in sight all the time, their presence was just noted and recorded. The Italian scientist Giuseppe Piazzi managed to capture a space object that was originally adopted for a comet, but its slow and uniform rotation has forced the scientist to assume that it is something else. Throughout the years, different researchers observed the detected celestial body and studied its properties, and by 31 December 1801 his presence and the situation was exactly confirmed. It was called Ceres by the name of the Roman goddess of fertility.
About fifty years officially carried the name of the planet but after the discovery of Ceres next to other similar celestial bodies, it acquired the status of an asteroid, object, whose name (“like a star”) and properties were described by William Herschel in 1802. So, that Ceres was the first asteroid, officially open.
Disputes scientists about the options and weight of the heavenly bodies, the presence or absence of the orbit, satellites and sufficient removal from other space objects has led to the fact that Ceres again began to consider a planet, although small. However, to fully meet all of the criteria of such objects is also not able, what was the reason for the creation and use of another classification is a dwarf planet. Today he is the official for the heavenly bodies, but as noticed by some scientists, that Ceres does not cease to be or not to be an asteroid. All this leads to a kind of confusion in the messages and statements of various organizations involved in the study and development of space, as well as in textbooks and methodological publications.
The discovery of the asteroids:
Officially, the era of the study of asteroids has its beginning since 1801, with the opening of Giuseppe Piazzi Cezary. After this discovery succeeded some others:
– Pallada – March 28, 1802., Heinrich Wilhelm Olbers;
– Juno – 1 September 1804г., Carl Harding;
– Vesta on 29 March 1807., G. V. Olbers;
– Astreya – December 8, 1845, Carl Ludwig Henke;
– Hebe – July 1, 1847, K. L. Henke;
– Irida – August 13, 1847, John Hind;
– Flora – October 18 1847г, D. hind;
– Metida – April 25, 1848., Andrew Graham;
– Gigeya, April 12, 1849., Annibale de Gasparis;
Of Partenope – may 11, 1850, Annibale de Gasparis;
Victoria – September 13, 1850., D. Hind;
– Egeria – 2 Nov 1850., Annibale de Gasparis;
– Irena – may 19, 1851., D. Hind;
– Evnomiya – July 29, 1851., Annibale de Gasparis;
– Psyche – March 17, 1851., Annibale de Gasparis;
– Thetis – 17 APR 1852г., Robert Luther;
– Melpomena – June 24 1852г., D. Hind;
Fortuna – August 22 1852г, D. hind;
The Massalia – 19 September 1852г., Annibale de Gasparis;
– Lutetium – November 15 1852г., Hermann Goldschmidt;
– Calliope – November 16 1852г., D. Hind;
– Waist – 15 Dec 1852г., D. Hind;
– Themis – April 5, 1853., Annibale de Gasparis;
– Foca – 6 APR 1853., Jean Chacornac;
– Proserpine – may 5, 1853., R. Luther;
– Euterpe – 8 Nov 1853., D. Hind;
– Bellona – March 1, 1854., R. Luther;
– Amphitrite – March 1, 1854., Albert March;
– Urania – July 22, 1854., D. Hind.
The discovery of new celestial objects continues to this day.
Well-known large asteroids in the solar system:
Count the exact number of asteroids, located in the vast Solar system, even with modern equipment of observatories is not possible, but the most significant of them studied well enough and even have their own names.
Ceres is not only the first open, but also the largest representative of this group of celestial bodies. the Diameter of the dwarf planet is 960 km and the shape of the object is quite correct, like the ball. The crust of the asteroid includes the thickness of the ice masses and a variety of minerals, the basis of the core – stone.
After providing the status of the Ceres dwarf planet Vesta has become a leader among Main-belt asteroids and the mass and diameter– 525,4 +/- 0,2 km has high brightness, so it can be seen from Earth with the naked eye. Vesta is rich in various minerals, mostly iron and Nickel.
The diameter of Pallas Vesta is slightly smaller around 512 +/-6 km, are included in the Main asteroid belt. It is established that at the facility there are hydrated minerals, making it particularly attractive for further study.
Interesting fact: his name asteroid was named friend of the Greek goddess of Pallas Athena, but in his honor was named the new chemical element palladium, opened by Englishman William Wollaston in 1803.
The diameter of Hygeia is just over 407,12 km, making it fourth. Despite the impressive size, was open quite late, because it has low albedo and quite far away from the Sun, causing poor visibility even in the most powerful telescopes. Mineral composition of the heterogeneous object are different chemical elements, among which there are also hydrated.
Interamnia completes the five largest celestial bodies in this group with a diameter of 326 km. Refers to a rare asteroid subclass of F, which is carbon, but not having even a trace of water in the composition, which directly indicates the presence of hydrated minerals.
Dia Europe is 302,5 km, it is a classic representative of carbonaceous asteroids. Distinctive feature is a marked and elongated orbit of a porous surface.
The exact dimensions of the object of David is not installed, according to various estimates, they range from 270 to 326 km. the Density is large enough and study with the help of infrared satellite has allowed to establish the presence of hydrated minerals. It received its name in honor of the American astronomy Professor David Todd, but the tradition to assign to the objects only women’s names led to the emergence of such an unusual name.
Sylvia is a triple object and part of the family of Cybele. It received its name in honor of the mother of the founders of Rome – Romulus and REM, whose names are called satellites of the asteroid. Diameter of a celestial body is 232 km, refers to carbon-rich silicates, including organic substances. A distinctive feature is the elongated shape of the object and a very high speed of rotation on the short axis.
Hector is a large and dark celestial body that belongs to the Trojan asteroids of Jupiter. Has an elongated shape similar to groundnuts (peanuts), with dimensions 370*195*205 km, which, according to scientists, suggests that it consists of two objects tied between the force of gravity. Is the only Trojan asteroid, with a companion, and its surface consists mostly of rock and ice strata.
Euphrosynos is the classical representative of the asteroid class, but are characterized by very high rotation speed. Diameter– 255,9+/-5,8 km has a low albedo, which is almost never visible from the Earth, which indicates the richest carbon stocks and the high density object.
Asteroids approaching to the Earth:
Small celestial bodies periodically come closer to the Earth’s orbit, and at the dawn of the formation of the Solar system occasionally fell on the planet’s surface. This is evidenced by the presence of the same minerals in the earth’s crust and the cores of asteroids, i.e., you can assume that the modern development of the fields is a development of the past fallen in to the Earth of small celestial bodies. However, this decline can become catastrophic for humanity and lead to the death of the entire planet, so potentially dangerous objects (about ten) that significantly closer to it that you are monitoring.
In the entire history of space exploration scientists observed 3 similar asteroid:
– 2004 FU 162 – flew in the distance 6535 km 31 March 2014
– 2008 TS 26 – approached to a distance of up to 6150 miles October 9, 2008,
– 2009 VA – was at a distance of 14 million km from Earth November 6, 2009
All in all, scientists was 6200 asteroids whose orbit is close to Earth, but the observation of most of them is difficult or impossible. Particularly noteworthy are the heavenly bodies whose diameter exceeds 1 km, because their fall can result in powerful explosions and destruction.
What distinguishes a meteorite from the asteroid?
Celestial bodies do not differ a great variety, but when you change their position in space of the solar system, they change its properties, from what others have done.
So, asteroids whose size may reach hundreds of kilometers in diameter, not very much, but the belt of these objects (asteroids “seeking to unite”) includes more than 750 thousands of smaller, medium and even very small celestial bodies. they are All moving along a certain orbit, but as a result of various forces and processes, it is sometimes “frustrated” with her and moving in space. If one of these asteroids enter the Earth’s atmosphere, it becomes a meteor.
To reach the surface of the planet the meteor will have to face several layers of the atmosphere, where his body will be subjected to various chemical and physical processes, in other words – “burn”. In the case when some part of the meteor will still remain intact and fall to the Ground, it becomes a meteorite. Most often it is the former core of an asteroidcomposed mostly of iron (90%) or minerals – silicon, magnesium and others. The fireball produced by the explosion and burning of the meteor in the atmosphere is called a bolide.
What distinguishes a comet from an asteroid?
Comet and asteroid are completely different celestial bodies, although they have a lot in common:
– the composition of the object. The basis of the asteroid substances, which are called minerals. Most often it is the metals, but there are minerals, including hydrated, carbon, rocky materials. The basis of comet – ice mass and dust, supplemented by a small number of rocky substances;
– the place of formation. Both kinds of objects was formed at the time of formation of the Solar system about 4.5 billion years ago. However, the asteroid located relatively close to the main star and its thermal radiation, causing ice and even water on them became impossible. The comet is located remotely, which is reflected in their composition, but when approaching the Sun, their mass decreases sharply, as ice masses melt and evaporate. As a result, the appearance of the characteristic “tail”, which the asteroid is absent;
– the orbit. Another fundamental difference between comets and asteroids: the first have a wide and fairly long trajectories, whereas short, arranged in a circle, although sometimes not quite the right shape. The latter leads to the fact that asteroids are “seeking to unite” and form a belt;
– not the most fundamental, but still the difference is considered and the number of celestial bodies. today, scientists open a little more than 3.5 thousand of comets, while the estimated number of asteroids greater than a few million. Count all such bodies is impossible, since many of them do not exceed the parameters of dust particles.
Than asteroids differ from dwarf planets?
The main difference between these two types of celestial bodies is mass, and accordingly, the shape of the object.
So, the total is:
the orbits in which they revolve around the Sun;
– exclusion from the category of satellites of other planets;
– inability to clear its orbit from other objects in the Universe along the way.
However, the mass of the dwarf planets enough to have gravitational forces. Under their action, bulges and protrusions “wminute”, “polished”, resulting in the spherical shape inherent in the object corresponding to the term “planet”. This fact allowed us to classify Ceres, long considered an asteroid, a dwarf planet (although officially from the list of last it is also not excluded).
Asteroids are too small mass in which it is impossible the emergence of gravity, so their wrong and very diverse.
Where are the asteroids?
The feature of the asteroids – combining them into families and groups arising on the basis of the nuances of spin in their orbits. The family is a fairly dense cluster of celestial bodies, and scientists are particles of the larger asteroids collided earlier in this part of the Universe. The group is a lesser number of objects and more loose cluster of celestial bodies. they, in turn, form a belt, of which there are five.
Main asteroid belt:
The main asteroid belt located between the orbits of Mars and Jupiter. It got its name due to the size, i.e. the largest number of celestial bodies in its composition. Its total mass is about 4% of the mass of the main satellite of the Earth, and the main “advantage” is the presence of four major giants: Ceres, Vesta, Pallas and Hygeia.
The number of asteroids in the belt up to several million, with more than half of them of small size, up to 30-50 meters in diameter, and they are located at a considerable distance from each other, which allows space vehicles to move freely between them.
As part of the Main belt has several major families:
There are also young families – Karina, Veritas, Datura, Iannini and Trojan asteroids, which are two major groups of celestial bodies situated on the border of the orbit of Jupiter.
The Kuiper Belt:
The Kuiper belt – the next largest cluster of asteroids located in the vicinity of the orbit of the planet Neptune. Although the number of celestial bodies themselves there is less, the area occupied by them in the two dozen times larger than the Main belt, because the distance between objects even more than in the first case. Another difference is the composition: in the Main belt they mainly include the ore and rock, and in the Kuiper belt – volatile substances, presented in the form of the ice masses. The most common are ammonia and methane.
The largest objects of focus are the celestial bodies the dwarf planet:
The scattered disk:
The scattered disk is located in a remote part of the Solar system where there are a small number of small celestial bodies, whose basis is the ice. Refer to the subfamily of TRANS-Neptunian objects located in the Kuiper belt, since the inner part of the disk intersects with it. However, allocated in a separate cluster, because the outer boundary is located at a considerable distance from the Sun.
The position of objects very fragile: they are able to be removed from the main cluster of tens of kilometers, for which he received the name – broken to be in the Kuiper belt or the Oort cloud. The largest objects are Eris and Sedna.
The Oort Cloud:
The Oort cloud is considered to be a hypothetical sphere clusters of small celestial bodies, mainly long-period comets, but its exact existence is doubted by some scholars. Located in the most remote part of the Solar system and is considered its conditional outer boundary, and its size, presumably a thousand times more than its nearest neighbors. Divided the Oort cloud into two areas – external and internal. The heavenly bodies, included in their composition, mainly include thickness of ice consisting of water, methane or ammonia. The main objects of the cloud:
– 2000 CR 105;
– 2006 SQ 372;
– 2008 KV 42;
– 2012 VP 113.
There are suggestions that it includes a gas giant planet Tyche, and for its external limits is star Nimezida satellite of the Sun.
The Orbit Of Saturn:
Saturn – second options planet in the Solar system and the sixth location from the main star – the Sun, which is a gas giant. It has a characteristic ring, in whose bounds is situated the orbits of a few asteroids, called Saturn-grossery.
The largest and most well known are:
– 1999 RG 33;
– 2001 BL 41;
– 2002 RP 120.
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