8 Flora
8 Flora is a big, bright, main belt asteroid. It is the closest big asteroid: no asteroid closer to the Sun has a diameter above 25 kilometres or two-elevenths that of Flora itself, and not until the tiny 149 Medusa was found was a single asteroid orbiting at a closer mean distance known.[6] It is the seventh brightest asteroid with a mean opposition magnitude of +8.7.[7] Flora can reach a magnitude of +7.9 at a favorable opposition near perihelion, such as will occur in mid November 2007.
 Size comparison: the first 10 asteroids profiled against Earth's Moon. Flora is third from the right. | |
| Discovery | |
|---|---|
| Discovered by | J.R. Hind |
| Discovery date | October 18, 1847 |
| Designations | |
| none | |
| Main belt (Flora family) | |
| Orbital characteristics | |
| Epoch November 26, 2005 (JD 2453700.5) | |
| Aphelion | 380.850 Gm (2.546 AU) |
| Perihelion | 277.995 Gm (1.858 AU) |
| 329.422 Gm (2.202 AU) | |
| Eccentricity | 0.1561 |
| 1193.549 d (3.27 a) | |
Average orbital speed | 19.95 km/s |
| 156.401° | |
| Inclination | 5.886° |
| 111.011° | |
| 285.128° | |
| Physical characteristics | |
| Dimensions | 145×145×120 km[1][2] |
| Mass | ~3.6×1018 kg |
Mean density | ~2.7 g/cm³[3] |
| ~0.045 m/s² | |
| ~0.081 km/s | |
| 0.5363 d (12.87 h)[4] | |
| Albedo | 0.243 (geometric)[1] |
| Temperature | ~180 K max: 276 K (+3 °C) |
Spectral type | S-type asteroid |
| 7.9[5] to 11.6 | |
| 6.49 | |
| 0.21" to 0.053" | |
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Discovery and naming
changeFlora was found by J. R. Hind on October 18, 1847. It was his second asteroid discovery after 7 Iris.
The name Flora was proposed by John Herschel, from Flora, the Latin goddess of flowers and gardens, wife of Zephyrus (the personnification of the West wind), mother of Spring, and whose Greek equivalent is Chloris (who has her own asteroid, 410 Chloris).
Characteristics
changeFlora is the parent body of the Flora family of asteroids, and by far the biggest member, having about 80% of the total mass of this family. But Flora was almost certainly disrupted by the impact(s) that formed the family, and is probably an aggregate of most of the pieces.
Flora's spectrum indicates that its surface is made of a mixture of silicate rock (including pyroxene and olivine) and nickel-iron metal. Flora, and the whole Flora family generally, are good candidates for being the parent bodies of the L chondrite meteorites.[8] This meteorite type comprises about 38% of all meteorites impacting the Earth.
Notable facts
changeDuring an observation on March 25, 1917, 8 Flora was mistaken for the star TU Leonis, which led to that star's classification as a U Geminorum cataclysmic variable star. This mistake was uncovered only in 1995.[9][10]
References
change- ↑ 1.0 1.1 "Supplemental IRAS Minor Planet Survey". Archived from the original on 2006-06-23. Retrieved 2007-12-17.
- ↑ Torppa, Johanna; Kaasalainen, Mikko; Michałowski, Tadeusz; Kwiatkowski, Tomasz; Kryszczyńska, Agnieszka; Denchev, Peter; Kowalski, Richard (2003). "Shapes and rotational properties of thirty asteroids from photometric data" (PDF). Icarus. 164 (2): 346. doi:10.1016/S0019-1035(03)00146-5. S2CID 119609765. Archived from the original (PDF) on 2015-11-06. Retrieved 2007-12-17.
- ↑ Krasinsky, G. (2002). "Hidden Mass in the Asteroid Belt". Icarus. 158: 98. doi:10.1006/icar.2002.6837.
- ↑ "Planetary Data System Small Bodies Node, lightcurve parameters". Archived from the original on June 14, 2006.
- ↑ Donald H. Menzel and Jay M. Pasachoff (1983). A Field Guide to the Stars and Planets (2nd ed.). Boston, MA: Houghton Mifflin. p. 391. ISBN 978-0-395-34835-2.
- ↑ Binsel, Richard P.; Gehrels, Tom and Matthews, Mildred Shapley (editors); Asteroids II; published 1989 by University of Arizona Press; pp. 1038-1040. ISBN 978-0-8165-1123-5
- ↑ "The Brightest Asteroids". Archived from the original on 2010-01-17. Retrieved 2007-12-17.
- ↑ Nesvorný, D.; Morbidelli, A.; Vokrouhlický, D.; Bottke, W.F.; Brož, M. (2002). "The Flora Family: A Case of the Dynamically Dispersed Collisional Swarm?". Icarus. 157: 155. doi:10.1006/icar.2002.6830.
- ↑ "IAUC 6174". [dead link]
- ↑ Schmadel, L. D.; Schmeer, P.; Börngen, F. (1996). "TU Leonis = (8) Flora: the non-existence of a U Geminorum star". Astron. Astrophys. 312: 496. Bibcode:1996A&A...312..496S.
Other websites
change- shape model deduced from lightcurve Archived 2015-11-06 at the Wayback Machine
- "Announcement of discovery of Flora", MNRAS 8 (1848) 82
- Orbital simulation from JPL (Java)
- 8 Flora at opposition Nov 15th, 2007 (0.89AU from Earth)
- Yeomans, Donald K. "Horizons system". NASA JPL. Retrieved 2007-03-20. — Horizons can be used to obtain a current ephemeris.
