8 Flora

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8 Flora 8 Flora Astronomical Symbol.svg
Moon and Asteroids 1 to 10.svg
Size comparison: the first 10 asteroids profiled against Earth's Moon. Flora is third from the right.
Discovered byJ.R. Hind
Discovery dateOctober 18, 1847
Other namesnone
CategoryMain belt (Flora family)
Reference date November 26, 2005 (JD 2453700.5)
Longest distance from the Sun380.850 Gm (2.546 AU)
Shortest distance from the Sun277.995 Gm (1.858 AU)
Longest distance from the center of its orbital path
("semi-major axis")
329.422 Gm (2.202 AU)
How long it takes to complete an orbit1193.549 d (3.27 a)
Average speed19.95 km/s
Mean anomaly156.401°
Angle above the reference plane
Size and other qualities
Measurements145×145×120 km[1][2]
Mass~3.6×1018 kg
Average density~2.7 g/cm³[3]
Surface gravity~0.045 m/s²
Escape velocity~0.081 km/s
Rotation period0.5363 d (12.87 h)[4]
How much light it reflects0.243 (geometric)[1]
Avg. surface temp.~180 K
max: 276 K (+3 °C)
Spectral typeS-type asteroid
Seeming brightness
("apparent magnitude")
7.9[5] to 11.6
True brightness
("absolute magnitude")

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.

Discovery and naming[change | change source]

Flora 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[change | change source]

Flora 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[change | change source]

During 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 | change source]

  1. 1.0 1.1 "Supplemental IRAS Minor Planet Survey".[dead link]
  2. Torppa, J.; et al. (2003). "Shapes and rotational properties of thirty asteroids from photometric data". Icarus 164: 346. http://www.rni.helsinki.fi/~mjk/thirty.pdf. 
  3. Krasinsky, G. A.; et al. (2002). "Hidden Mass in the Asteroid Belt". Icarus 158: 98. 
  4. "Planetary Data System Small Bodies Node, lightcurve parameters". Archived from the original on June 14, 2006.
  5. Donald H. Menzel and Jay M. Pasachoff (1983). A Field Guide to the Stars and Planets (2nd edition ed.). Boston, MA: Houghton Mifflin. p. p. 391. ISBN 978-0-395-34835-2.CS1 maint: Extra text (link)
  6. 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
  7. The Brightest Asteroids Archived 17 January 2010 at WebCite
  8. Nesvorný, D.; et al. (2002). "The Flora Family: A Case of the Dynamically Dispersed Collisional Swarm?". Icarus 157: 155. 
  9. "IAUC 6174".[dead link]
  10. Schmadel, L. D.; Schmeer, P.; Börngen, F. (08 1996). "TU Leonis = (8) Flora: the non-existence of a U Geminorum star". Astron. Astrophys. 312: 496. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1996A%26A...312..496S&db_key=AST&data_type=HTML&format=&high=43a5c7f7b428230. 

Other websites[change | change source]