Department of Physics AstroLab

Orbits of Main-Belt Asteroids

Apart from the major planets, the Solar System contains a large number of smaller bodies. The asteroids (i.e. the minor planets) are the small rocky objects that are found mainly between the orbits of Mars and Jupiter. So far over 700,000 have been catalogued. The largest, Ceres, has a diameter of 1000 km (i.e. 30% of the Moon diameter).

The aim of the project is to independently determine the orbits of several (~8) asteroids by making a series of positional measurements. This is achieved by measuring the asteroid's position on a CCD image relative to that of catalogued stars. Asteroids typically move about 10 arcmin per 24 hours. By tracking an asteroid over the term its orbit can be well determined. The goal will be to obtain about 10 observations per asteroid.

By reference to the UCAC4 star catalog, astrometry measurements can be made with uncertainties of better than 0.1 arcsec. The plot below compares the measured astrometric positions with the asteroid positions predicted from the JPL Horizons On-line Ephemeris. JPL's formal +/− 1, 2, 3 standard-deviation uncertainties are shown as error ellipses; these are described as "optimistic" (see Horizons Manual).

The minor planet Chloe was observed on seven different occasions during the 2005 Epiphany term by Astrolab students (David and Rob). Their results table for Chloe is given here. This table illustrates the type of positional measurements that can be obtained for this project.

Since 1994 the following minor planets have been observed from Durham

1994 Juno, Kleopatra, Vesta, Massalia, Niobe, Harmonia, Eunomia
1995 Ceres, Harmonia, Vesta, Eugenia, Astraea, Ganymede, Beira, Flora, Aten, Partenope, Eunomia, 1992ac, Phocaea, Niobe, Eros
1996 Hilda, Niobe, Doris, Iris, Eros, Phyche, Juno, Klio, Hygiea
1999 Massalia, 1998PG, Kemi, Summerfield, Ampella, Lumen, Mnemosyne, Io, 1999 RH27, Hela
2000 Hebe, Hispania, Amphitrite, Ariadne, Feronia, Irene, Iris, Phocaea, Corduba, Camilla, Herculina, Zwetana, Scheila, Pax. Hypatia, Athamantis, Doris, Lampetia, Nausikaa, Thisbe, Urania.
2001 Psyche, Pomona, Angelina, Klio, Agnes
2002 Doris, Harmonia, Kalliope, Lomia, Parthenope, Philosophia, Thalia, Iris, Phocaea, Feronia, Penelope, Gyptis, Eunomia
2003 Ausonia, Klio, Io, Ampella, Kleopatra, Semiramis, Phaedra
2004 Hebe, Eunomia, Proserpina, Antigone, Aurora, Devosa, Niobe, Ursula, Hertha, Palisana, Mnemosyne, Andromache
2005 Io, Dione, Phaedra, Athamantis, Caecilia, Emma, Bettina, Russia, Klio, Chloe, Schlutia, Valeska, Xenia, Anna, Galene, Hedwig, Erminia, Cloelia, Zerbinetta, Hansa, Helio, Aethra, Scheherezade, Leonora.
2006 Fortuna, Danae, Julia, Juvisia, Christine, Josefa, Juewa, Thia, Ursula, Etherdgea, Newcombia, Phocaea, Aspasia, Messalina, Mocia, Athene, Hel, Cohina, Swasey, Astarte, Devosa, Irma, Isolda
2007 Kalliope, Anna, Kreusa, Timandra, Galilea, Inhilde, Baucis, Dodona, Edna, Patricia, Victoria, Ilmatar, Gunload, Hel, Hybris, Marianna, Mitsursoohba
2008 Alauda, Aurora, Hanskya, Herschel, Hertha, Kleopatra, Palisana, Tarka, Thia, Tinette, (9068) 1993 OD, (12377) 1994 PP
2010 Danae, Tisiphone, Persephone, Athene, Piazzia, Aegle, Atalante, Devosa, Maria
2011 Ursula, Heidelberga, Lampetia, Vaticana, Massinga, Thisbe, Psyche, Zelinda, Oppavia, Lamberta, Weaver, Arabella, Lomia, Athamantis
2012 Ampella, Proserpina, Galilea, Aspasia, Irma, Kalliope, Felicitas, Astarte, Zerbinetta, Athene, Niobe, Dodona, Mocia, Marion, Zerlina, Nolli
2013 Lomia, Antigone, Hertha, Lamberta, Russia, Kreusa, Herschel, Hannibal, vanGogh
2014 Angelina, Fortuna, Hel, Herculina, Io, Marianna, Messalina, Parthenope, Thia, Tinette, Xenia, 1993 OD, Aethra, Fay, Mayall, Sequoia, Vanphilos. Kilo

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