asteroide.GIF (2469 bytes)  A S T E R O I D S

 

Sizes and orbits

         The more representative asteroids of greater size and they are: Ceres, with a diameter of 1.030 km, Pallas & Vesta, with diameters of 450 km. Approximately 200 asteroids have diameters of more of 100 km, & exist thousands of smaller asteroids. The total mass of all asteroids of the Solar System is much smaller than the mass of the Moon. The greatest bodies are more or less spherical, but those that have smaller diameters of 160 km usually present/display extended & irregular forms. Most of asteroids, without considering his size, they take of 5 to 20 hours in completing a turn on his axis.

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       Some asteroids have companions like the surprise that went when photographing the asteroid Ida & its small Dactil moon.

   

            At the present time, few scientists think that the asteroids are the rest of a previous planet. Most probable it is than the asteroids occupy a place in the Solar System where a planet of considerable size could have been formed, but could not be by the disruptive Jupiter influences. Perhaps at first, few dozens of asteroids existed that later fragmented in mutual collisions until producing the present number.

 

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Asteroid belt.

     In her she is reflected the first 6,000 catalogued asteroids. It is possible to be observed that the majority is between the orbit of Mars & Jupiter, few enter the orbit of inner planets denominated Apolo & those that they orbit to 60º previous & later to Jupiter in his orbit, denominated troyans.

 

            The calls Troyans asteroids are located in two clouds, one that turns 60° in front of Jupiter, in the plane of its orbit, & the other 60° behind. In 1977, the asteroid Chiron was discovered in an orbit between the one of Saturn & the one of Uranus. At the beginning of the decade of 1990 it was discovered that about 75 asteroids (the asteroids of Amor) crossed the Mars orbit, about 50 (the asteroids of Apolo) crossed the Earth orbit & less than 10 (the asteroids of Atón) they have orbits smaller than the one of the Earth. One of greater inner asteroids is Eros, with a diameter of 24,7 km. a strange asteroid of Apolo, Faetón, of 5 km of wide, approaches the Sun more than any other well-known asteroid (20.9 million km). Also is related to him to the annual return of the meteor shower current of Géminids.

 

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            Some of the asteroids that approach the Earth are objective relatively easy for the space missions. In 1991, the space probe of the NASA Galileo, in its trip to Jupiter, caught the first plane of an asteroid. The images show that the small body, 951 Gaspra, is sprinkled of craters & reveal the existence of a mantle of a fragmentary or regolito material that covers the surface with the asteroid.

 

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Maxima approach of sounding NEAR to the Eros asteroid, the image of the right is made next to the South Pole of the asteroid
 

 

Composition of the surface

        One thinks that most of meteorites recovered in the Earth they are asteroid fragments. The asteroid observations by means of espectroscopia by telescope & by radar support this hypothesis. They demonstrate that the asteroids, like the meteorites, can be classified in few types. The three fourth parts of visible asteroids from the Earth, including Ceres, belong to type C, which seems to be related to a meteorite class known like carbonacs condrits. It is considered that they are the oldest materials of the Solar System, with a composition that reflects the one of primitive solar nebulas. Of very dark color, probably caused by his hydrocarbon content, they present/display tests of to have adsorbed hidratación water. Therefore, unlike the Earth & of the Moon, never they have softened or reheated since they formed.

         The asteroids of the S type, related to stony-ferrous meteorites, approximately constitute 15% of the total number.

           Much more rare they are the objects of type M, that correspond by their composition to ferrous meteorites. Composed of an alloy of iron & nickel, they represent the nuclei of the softened & differentiated planetary bodies, to which the impacts undressed of their external layers.

      Perhaps few asteroids, among them Vesta, are related to the strangest meteorite class: the acondritos. These asteroids seem to have in their surface a similar igneous composition to the one of many terrestrial & lunar lava torrents. For that reason, the astronomers are reasonably safe that Vesta, at some moment of its history, softened of partial form. The scientists are disturbed before the fact that some of asteroids have softened & others, like Ceres, no. A possible explanation is that the primitive Solar System contained certain concentrated isotopes, very radioactive, that had generated the heat sufficient to soften to asteroids.

 

Discovered to date

        Next it is the relation of asteroids discovered & located until date.  They are different works where it is located to the place of observation & location of the asteroid in question as well as all the information of the asteroid & its present location so that you prune to locate it without problems. If they wish more information they can write me to my  Correo / E-mail

 

Asteroid N. Discovery date Notes
Astraea

5

May 26th, 2000

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Athamantis

230

November 1st, 2000

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Bamberga

324

October 27th, 2000

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Bellona

28

February 15th, 2002

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Ceres

1

September 3rd, 1988

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Eunomia

15

July 31st, 1989

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Euterpe

27

March 20th, 2002

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Flora

8

August 27th, 2000

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Hebe

6

November 8th, 1999

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Hygiea

10

May 29th, 2000

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Iris

7

February 27th, 2000

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Juno

3

November 19th, 1996

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Massalia

20

June 10th, 1989

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Melpomene

18

September 5th, 1988

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Metis

9

February 7th, 2002

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Nausika

192

October 3th, 2000

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Nysa

44

April 5th, 2000

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Pallas 

2

May 21st, 2001

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Vesta

4

March 26th, 1988

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 Masm © (Last update 10.11.2006)