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ASTEROIDS

ASTEROIDS. “The asteroids are of no interest to the amateur observer; in fact, they are of little interest to anybody” - G.F. Chambers 1 “The Vermin of the skies.” - Unknown. A Little History. Since 1847, there has been at least one new asteroid discovered every year.

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ASTEROIDS

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  1. ASTEROIDS “The asteroids are of no interest to the amateur observer; in fact, they are of little interest to anybody” - G.F. Chambers1 “The Vermin of the skies.” - Unknown

  2. A Little History... • Since 1847, there has been at least one new asteroid discovered every year. • The first asteroid, named Ceres, was discovered on January 1, 1801 by G. Piazzi in Palermo, Italy. • Asteroid names are preceded by a number according to its order of discovery. • 1 Ceres, along with, 2 Pallas, 3 Juno, and 4 Vesta were all discovered by 1807 and are often called “The Big Four”.

  3. First Come, First Serve • An asteroid will initially be named for the year it was discovered, along with a lettering system indicating date and order or discovery. • The person who has discovered the asteroid is allowed to name it. 1 Ceres3

  4. What is an Asteroid? • An asteroid is a body in the solar system that revolves around the sun, that is larger than a meteorite, but smaller than a planet. • The word asteroid is a vague classification as it typically refers only to objects within the orbit of Jupiter . • However, there are asteroid-like objects scattered throughout our solar system. • Other than their location, these objects all share the same characteristics.

  5. Formation • Asteroids were likely formed in the same way that planets were, through remnants of the solar nebula. • When Jupiter reached its current size its gravity caused the dispersion of the bodies into the asteroid belt (orbital resonance). Solar Nebula4

  6. Physical Characteristics • Asteroids vary greatly in size. • Note that the diameter is a mean, the non-uniform shape is an inherent part of being an asteroid. • Despite their huge numbers, all the asteroids between Mars and Jupiter are only equal to 4% of the mass of the moon. Asteroid Population5

  7. Top 10 Asteroids By Diameter • While diameters are precise, measuring the mass is • much more difficult. Errors as high as 30% can occur.

  8. Composition • Classified by their spectral and mineral characteristics • Spectral - the most populous groups • C – Carbonaceous asteroids • S – Silicaceous asteroids • M – Metallic asteroids • Mineral composition is a poor tool for classification. • Relies on albedo, spectrum, and density

  9. Asteroid Spectrum7

  10. 10 Brightest Asteroids • To add some context, the brightest asteroid, 4 Vesta, at an apparent magnitude of 5.1 is between Uranus (5.4), and Ganymede (4.4).

  11. Location • Typically grouped in terms of distance to the sun. • Families can have as few as 10, and as many as several hundred asteroids. • Grouped as: • From sun to Earth • Earth to Mars • Mars to Asteroid Belt • Asteroid Belt • Belt to Jupiter • Beyond Jupiter • Beyond Neptune Main asteroid belt between Mars and Jupiter2

  12. Major Asteroid Belt Families (AU from sun) Hungaria 1.8 – 2.0 Flora 2.2 Maria 2.25 Phocaea 2.4 Koronis 2.8 – 2.9 Budrosa 2.9 Eos 2.0 Themis 3.1 Hilda 4.0 • There are many asteroid families, the vast majority are found in the Asteroid Belt. • Some other major asteroid types include: • Trojans - lie either 60 degrees ahead of or behind a planet in orbit. • Helgas - are found between the Trojans and the Asteroid Belt. • Kuiper Belt – A belt found outside of the orbit of Neptune, roughly 20 times as wide and 20 to 200 times as numerous. (not actually asteroids, minor planets) Kuiper Belt8

  13. How Do We Know? • Limited information can be determined from light curves, the change in brightness as they rotate. • Spectral properties. • Timing the length of star occulations. • Radar imaging, telescopes. • Photography by flyby space probes. • The NEAR Shoemaker probe landed on 433 Eros in 2001.

  14. Leave it to the Professionals • DAMIT – An accurate 3D database of asteroid models. 68 LETO9

  15. Solar sails for prevention of NEO catastrophes • This journal cites 99942 Apophis specifically10 • The surface of 1Ceres is 10-15 % water.11 • Ultra low delta-v asteroids12 • Delta V refers to energy required to reach an object • There are many asteroids that take less energy to reach than the moon.

  16. Areas of Study • NEO asteroids can cause danger to Earth. • 99942 Apophis has a 1/250000 chance of hitting Earth on April 13, 2006. • Remnants of the creation of the universe. • Asteroid impacts account for the deposition of surface minerals and shaping of other planetoids. • Seeding of life, presence of amino acids and organic compounds. • Mining for minerals.

  17. Citations • 1) P. Moore, Patrick Moore’s Data Book of Astronomy, edited by Patrick Moore and Robin Rees ( Cambridge University Press, New York), pp 156 – 178. • 2) Pluto & the Kuiper Belt, Aerospace Web, http://www.aerospaceweb.org/question/astronomy/q0270.shtml. • 3)1 Ceres, Nine Planets, http://nineplanets.org/ceres.html. • 4) Solar nebula, Descriptive Astronomy, http://rhig.physics.wayne.edu/AST2010/Units/Unit33/index.htm.

  18. 5) William F. Bottke, Jr. [et al], Asteroids III, Over 150 collaborating editors and authors, (University of Arizona Press ; Houston : Lunar and Planetary Institute, c2002). • 6) Asteroids, Journey Through the Galaxy, http://burro.cwru.edu/stu/advanced/asteroid.html. • 7)Clark R. Chapman, David Morrison, Ben Zellner, Surface properties of asteroids: A synthesis of polarimetry, radiometry, and spectrophotometry, Icarus 25, 104-130, May 1975. • 8) Kuiper Belt, IAU Minor Planet Centre, The MPC Orbit (MPCORB) Database, http://www.minorplanetcenter.net/iau/MPCORB.html. • 9) J. ˇDurech, V. Sidorin, and M. Kaasalainen, DAMIT : Database of Asteroid Models, Astronomy & Astrophysics, Volume 513, Article 6, Jan 2010, http://adsabs.harvard.edu/abs/2010A%26A...513A..46D.

  19. 10) Shengping Gong, Junfeng Li, XiangyuanZeng, Utilization of H-reversal Trajectory of Solar Sail for Asteroid Deflection, Research in Astronomy and Astrophysics, Volume 11, Issue 10, pp. 1123-1133 (2011) http://arxiv.org/ftp/arxiv/papers/1108/1108.3183.pdf • 11) Larry A. Lebofsky, Asteroid 1 Ceres : evidence for water of hydration, Royal Astronomical Society, Monthly Notices, vol. 182, Feb. 1978, p. 17P-21P, http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1978MNRAS.182P..17L&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf • 12) Martin Elvis1 and Jonathan McDowell, Ultra-Low Delta-v Objects and the Human Exploration of Asteroids, Planetary and Space Science, Volume 59, Issue 13, p. 1408-1412, http://arxiv.org/ftp/arxiv/papers/1105/1105.4152.pdf

  20. Curtis Peebles, Asteroids: A History, Smithsonian Institution Press, 2000 • Various Authors, Asteroid Rendezvois : Edited by Jim Bell and Jacqueline Mitton, Cambridge University Press, 2002 • Apophis, Asteroid Apophis, http://asteroidapophis.com/

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