Discovery
Designations
category
Physical characteristics
128 km (mean)
145×145×120 km[3]
4.3×1018 kg[4][5]
~3.3 g/cm³[6]
max: 276 K (+3 °C)
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Discovery
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| Discovered by | J.R. Hind |
| Discovery date | October 18, 1847 |
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Designations
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| Alternate name | none |
| Minor planet category |
Main belt (Flora family) |
| Adjective | Florian |
| Epoch November 26, 2005 (JD 2453700.5) | |
| Aphelion | 380.850 Gm (2.546 AU) |
| Perihelion | 277.995 Gm (1.858 AU) |
| Semi-major axis | 329.422 Gm (2.202 AU) |
| Eccentricity | 0.1561 |
| Orbital period | 1193.549 d (3.27 a) |
| Average orbital speed | 19.95 km/s |
| Mean anomaly | 156.401° |
| Inclination | 5.886° |
| Longitude of ascending node | 111.011° |
| Argument of perihelion | 285.128° |
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Physical characteristics
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| Dimensions | 136×136×113 km[2] 128 km (mean) 145×145×120 km[3] |
| Mass | 8.47×1018 kg[2] 4.3×1018 kg[4][5] |
| Mean density | 7.75±0.92 g/cm³[2] ~3.3 g/cm³[6] |
| Equatorial surface gravity | ~0.045 m/s² |
| Escape velocity | ~0.081 km/s |
| Rotation period | 0.533 d (12.799 h)[1] |
| Albedo | 0.243 (geometric)[1] |
| Temperature | ~180 K max: 276 K (+3 °C) |
| Spectral type | S-type asteroid[1] |
| Apparent magnitude | 7.9[7] to 11.6 |
| Absolute magnitude (H) | 6.49[1] |
| Angular diameter | 0.21" to 0.053" |
8 Flora (pronounced /ˈflɔərə/, Latin: Flōra) is a large, bright main belt asteroid. It is the innermost large 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 discovered was a single asteroid orbiting at a closer mean distance known[8]. It is the seventh brightest asteroid with a mean opposition magnitude of +8.7[9]. Flora can reach a magnitude of +7.9 at a favorable opposition near perihelion, such as occurred in November 2007. Flora may be the residual core of an intensely heated, thermally evolved, and magmatically differentiated planetesimal which was subsequently disrupted.[10]
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Flora was discovered 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 personification of the West wind), mother of Spring, and whose Greek equivalent is Chloris (who has her own asteroid, 410 Chloris).
Lightcurve analysis indicates that Flora's pole points towards ecliptic coordinates (β, λ) = (16°, 160°) with a 10° uncertainty.[3] This gives an axial tilt of 78°, plus or minus ten degrees.
Flora is the parent body of the Flora family of asteroids, and by far the largest member, comprising about 80% of the total mass of this family. Nevertheless, Flora was almost certainly disrupted by the impact(s) that formed the family, and is probably a gravitational aggregate of most of the pieces.[citation needed]
Flora's spectrum indicates that its surface composition is 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.[11] This meteorite type comprises about 38% of all meteorites impacting the Earth.
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.[12][13]
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