Minggu, 12 April 2020

Asteroid Belt - Wikipedia Asteroid Names

Asteroid belt - Wikipedia

The asteroids of the inner Solar System and Jupiter: The belt is located between the orbits of Jupiter and Mars.

.

Asteroid belt - Wikipedia

The asteroid belt is a (whose diameter is 1200 km).

).

The asteroid belt formed from the primordial objects.

On 22 January 2014,

History of observation[]

noticed in 1596 irregularities in the orbits of Mars and Jupiter, which were later explained by the gravity from the asteroids.

In 1596, in 1781, the planet's orbit matched the law almost perfectly, leading astronomers to conclude that there had to be a planet between the orbits of Mars and Jupiter.

Asteroid belt - Wikipedia

, the largest object in the asteroid belt. Ceres was known as a planet, but later reclassified as an asteroid and from 2006 as a dwarf planet.

On January 1, 1801, Giuseppe Piazzi, chair of astronomy at the of all eight planets of the time (Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn and Uranus).

Fifteen months later, .

Accordingly, in 1802, William Herschel suggested they be placed into a separate category, named "asteroids", after the

Neither the appellation of planets nor that of comets, can with any propriety of language be given to these two stars ... They resemble small stars so much as hardly to be distinguished from them. From this, their asteroidal appearance, if I take my name, and call them Asteroids; reserving for myself, however, the liberty of changing that name, if another, more expressive of their nature, should occur.

By 1807, further investigation revealed two new objects in the region: Modern asteroid survey systems now use automated means to locate new minor planets in ever-increasing quantities.

Asteroid belt - Wikipedia

Origin[]

The asteroid belt showing the orbital inclinations versus distances from the Sun, with asteroids in the core region of the asteroid belt in red and other asteroids in blue

Formation[]

In 1802, shortly after discovering Pallas, Olbers suggested to Herschel that Ceres and Pallas were . This gravitational accretion led to the formation of the planets.

Planetesimals within the region which would become the asteroid belt were too strongly

Evolution[]

The asteroids are not samples of the primordial Solar System. They have undergone considerable evolution since their formation, including internal heating (in the first few tens of millions of years), surface melting from impacts, In 2006 it was announced that a population of

Characteristics[]

, a carbonaceous chondrite that fell to Earth in Mexico in 1969

Asteroid belt - Wikipedia

Contrary to popular imagery, the asteroid belt is mostly empty. The asteroids are spread over such a large volume that it would be improbable to reach an asteroid without aiming carefully. Nonetheless, hundreds of thousands of asteroids are currently known, and the total number ranges in the millions or more, depending on the lower size cutoff. Over 200 asteroids are known to be larger than 100 km,

Composition[]

The current belt consists primarily of three categories of asteroids: C-type or carbonaceous asteroids, S-type or silicate asteroids, and M-type or metallic asteroids.

removed.

The spectra of their surfaces reveal the presence of silicates and some metal, but no significant carbonaceous compounds. This indicates that their materials have been significantly modified from their primordial composition, probably through melting and reformation. They have a relatively high albedo and form about 17% of the total asteroid population.

One mystery of the asteroid belt is the relative rarity of However, due to rotation, the surface temperature of an asteroid can vary considerably as the sides are alternately exposed to solar radiation and then to the stellar background.

Main-belt comets[]

Several otherwise unremarkable bodies in the outer belt show

Orbits[]

The asteroid belt (showing eccentricities), with the asteroid belt in red and blue ("core" region in red)

Most asteroids within the asteroid belt have orbital eccentricities of less than 0.4, and an inclination of less than 30°. The orbital distribution of the asteroids reaches a maximum at an eccentricity of around 0.07 and an inclination below 4°., some asteroid orbits can be highly eccentric or travel well outside the ecliptic plane.

Sometimes, the term main belt is used to refer only to the more compact "core" region where the greatest concentration of bodies is found. This lies between the strong 4:1 and 2:1

Kirkwood gaps[]

)

  Zone II: middle main-belt (2.5 AU < a < 2.82 AU)

  Zone III: outer main-belt (a > 2.82 AU)

The or due to prior perturbations or collisions) are gradually nudged into different, random orbits with a larger or smaller semi-major axis.

Collisions[]

, a minor part of which is created by dust from collisions in the asteroid belt

The high population of the asteroid belt makes for a very active environment, where collisions between asteroids occur frequently (on astronomical time scales). Collisions between main-belt bodies with a mean radius of 10 km are expected to occur about once every 10 million years. Conversely, collisions that occur at low relative speeds may also join two asteroids. After more than 4 billion years of such processes, the members of the asteroid belt now bear little resemblance to the original population.

Along with the asteroid bodies, the asteroid belt also contains bands of dust with particle radii of up to a few hundred

Meteorites[]

Some of the debris from collisions can form

Families and groups[]

This plot of orbital inclination (ip) versus eccentricity (ep) for the numbered main-belt asteroids clearly shows clumpings representing asteroid families.

In 1918, the Japanese astronomer Smaller associations of asteroids are called groups or clusters.

Some of the most prominent families in the asteroid belt (in order of increasing semi-major axes) are the The largest asteroid to be a true member of a family (as opposed to an interloper in the case of Ceres with the

The main belt evolution after the Late Heavy Bombardment was very likely affected by the passages of large Centaurs and trans-Neptunian objects (TNOs). Centaurs and TNOs that reach the inner Solar System can modify the orbits of main belt asteroids, though only if their mass is of the order of 10−9  for single encounters or, one order less in case of multiple close encounters. However Centaurs and TNOs are unlikely to have significantly dispersed young asteroid families in the main belt, but they can have perturbed some old asteroid families. Current main belt asteroids that originated as Centaurs or trans-Neptunian objects may lie in the outer belt with short lifetime of less than 4 million years, most likely between 2.8 and 3.2 AU at larger eccentricities than typical of main belt asteroid.

Periphery[]

Skirting the inner edge of the belt (ranging between 1.78 and 2.0 AU, with a mean semi-major axis of 1.9 AU) is the The Phocaea family orbit between 2.25 and 2.5 AU from the Sun.

Skirting the outer edge of the asteroid belt is the

New families[]

Some asteroid families have formed recently, in astronomical terms. The

Exploration[]

The first spacecraft to traverse the asteroid belt was missions have studied asteroids for a protracted period in orbit and at the surface.

See also[]

  • (The other ring of material, at about 30–60 AU)

References[]

  1. At the time this graph was made, Ceres was estimated to constitute one third of the mass of the Belt. More recent estimates place it at one quarter.
  2. ^ . Universe Today. Retrieved 2016-01-30.
  3. ^ .
  4. (PDF) on July 3, 2014.
  5. ^ For recent estimates of the masses of Ceres, Vesta, Pallas and Hygiea, see the references in the infoboxes of their respective articles.
  6. from the original on 29 September 2010. Retrieved 2010-09-27.
  7. . Universe Today. Retrieved 2016-01-30.
  8. ^ . CosmosUp. 2016-01-17. Retrieved 2016-01-30.
  9. . Space.com. Retrieved 2016-01-30.
  10. . Sky & Telescope. Retrieved 2014-04-30.
  11. .
  12. .
  13. ^ . Retrieved 22 January 2014.
  14. .
  15. .
  16. ^ on 2012-04-06. Retrieved 2007-10-01.
  17. ^ on 2012-05-24. Retrieved 2007-11-03.
  18. . Churchill College, Cambridge. Retrieved 2010-07-12.
  19. "Call the police! The story behind the discovery of the asteroids". Astronomy Now (June 2007): 60–61.
  20. . Online Etymology Dictionary. Etymology Online. Retrieved 2011-04-15.
  21. from the original on 12 August 2007. Retrieved 2007-07-25.
  22. .
  23. ^ on 2012-02-06. Retrieved 2007-04-20.
  24. Linda T. Elkins-Tanton, Asteroids, Meteorites, and Comets, 2010:10
  25. . astronomy.com. Retrieved 2014-01-22.
  26. .
  27. Mann, Robert James (1852). A Guide to the Knowledge of the Heavens. Jarrold. p. 171. and 1853, p. 216
  28. . The Edinburgh New Philosophical Journal. 5: 191. January–April 1857.: "[Professor Peirce] then observed that the analogy between the ring of Saturn and the belt of the asteroids was worthy of notice."
  29. . BBC. Retrieved 2007-04-20.
  30. .
  31. . YouTube. Retrieved 2011-04-15.
  32. . IAU Minor Planet Center. Retrieved 2011-04-04.
  33. . Open2.net. Retrieved 2007-05-15.
  34. ]
  35. . NASA Goddard Spaceflight Center. Retrieved 2007-04-25.
  36. . news.ufl.edu. 2018-07-02. Retrieved 2018-10-17.
  37. . NASA. Retrieved 2007-04-02.
  38. ^ (PDF) from the original on 21 February 2007. Retrieved 2007-03-22.
  39. .
  40. .
  41. .
  42. on 2012-01-24. Retrieved 2010-07-12.
  43. Clark, B. E.; Hapke, B.; Pieters, C.; Britt, D. (2002). "Asteroid Space Weathering and Regolith Evolution". Asteroids III. University of Arizona: 585. .
  44. .
  45. (PDF) from the original on 28 November 2007. Retrieved 2007-11-08.
  46. . Guidetothecosmos.com. Retrieved 2013-05-03.
  47. . UANews. Retrieved 2018-10-18.
  48. from the original on 13 May 2007. Retrieved 2007-04-12.
  49. .
  50. .
  51. . Space Daily. Retrieved 2007-10-27.
  52. on 1 May 2007. Retrieved 2007-04-20.
  53. . NASA JPL. Retrieved 2007-04-26. – search for asteroids in the main belt regions with a diameter >100.
  54. .
  55. ^ . Minor Planets Center. Retrieved 2010-10-27.
  56. .
  57. NASA Solar System Exploration.
  58. ^ . Retrieved 2008-09-06.
  59. .
  60. .
  61. ^ . NASA's Cosmos. Retrieved 2007-04-02.
  62. .
  63. . ESA/Hubble Press Release. Retrieved 12 November 2013.
  64. ^ .
  65. ^ . space.com. Retrieved 2007-10-14.
  66. .
  67. . YouTube.com. 2007-01-05. Retrieved 2011-05-21.
  68. , dated February 8, 2006.
  69. . JPL Solar System Dynamics. Retrieved 2018-02-26.
  70. . Retrieved 2007-02-04.
  71. .
  72. on March 3, 2012. Retrieved 2007-04-04.
  73. )
  74. ^ .
  75. .
  76. . ABC Science. Retrieved 2007-04-04.
  77. (PDF). NASA. Retrieved 2012-01-12.
  78. on 2012-03-10. Retrieved 2007-04-20.
  79. .
  80. from the original on 1 April 2007. Retrieved 2007-04-02.
  81. .
  82. .
  83. .
  84. .
  85. .
  86. . Retrieved 2011-04-04.
  87. .
  88. . New Scientist Space. Retrieved 2007-04-15.
  89. .
  90. .
  91. .
  92. .
  93. . nasa.gov. NASA. Retrieved 4 September 2015.
  94. . Space Daily. Retrieved 2007-04-14.

Further reading[]

  • Elkins-Tanton, Linda T. (2006). Asteroids, Meteorites, and Comets (First ed.). New York: Chelsea House. ]

    This audio file was created from a revision of the article "Asteroid belt" dated 2012-03-30, and does not reflect subsequent edits to the article. ()

    • Arnett, William A. (February 26, 2006). from the original on 18 April 2007. Retrieved 2007-04-20.
    • Cain, Fraser. from the original on 7 March 2008. Retrieved 2008-04-01.
    • from the original on 15 May 2007. Retrieved 2007-04-20.
    • Munsell, Kirk (September 16, 2005). on 24 May 2007. Retrieved 2007-05-26.
    • Plots of at Asteroid Dynamic Site
    • Staff (October 31, 2006). from the original on 11 April 2007. Retrieved 2007-04-20.
    • Staff (2007).

Past and

current
Flybys
Orbiters
Landers
Impactors
Sample return
Planned
  • (flyby, 2020-2021)
  • (multiple flybys, 2021)
  • (impactor and flyby, 2021)
  • (multiple flybys, 2022)
  • (orbiter, 2022)
  • (flyby, 2022)
  • (orbiter and landers, 2024)
  • (flyby, 2028)
Proposed
  • (orbiter, 2021)
  • (flyby of Pallas, 2022)
  • (multiple flybys, 2026-2029)
  • (sample return)
  • (nuclear impactor concept)
  • (multiple flybys)
  • (multiple flybys and sample return, 2026)
  • (spacecraft refueling concept)
  • (multiple flybys and sample return, 2024)
Cancelled or

not developed
Related
  • Probes are listed in chronological order of launch. Italics indicate currently active missions. indicates mission failures.