astro.wikisort.org - Asteroid

Flora (minor planet designation: 8 Flora) 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 (20% that of Flora), and not until 20-km 149 Medusa was discovered was an asteroid known to orbit at a closer mean distance.[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.

8 Flora

Discovery
Discovered by	J.R. Hind
Discovery date	18 October 1847
Designations
MPC designation	(8) Flora
Pronunciation	/ˈflɔːrə/
Named after	Flōra
Minor planet category	Main belt (Flora family)
Adjectives	Florian /ˈflɔːriən/
Orbital characteristics[1]
Epoch 26 November 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 (sidereal)	1193.549 d (3.27 a)
Mean anomaly	156.4°
Inclination	5.886°
Longitude of ascending node	111.0°
Argument of perihelion	285.1°
Proper orbital elements[2]
Proper semi-major axis	2.2014 AU
Proper eccentricity	0.1449
Proper inclination	5.574°
Proper mean motion	110.2 deg / yr
Proper orbital period	3.26679 yr (1193.194 d)
Precession of perihelion	32.017 arcsec / yr
Precession of the ascending node	−35.51 arcsec / yr
Physical characteristics
Dimensions	c/a = 0.82±0.05[3] 136 km × 136 km × 113 km[4] 145 km × 145 km × 120 km[5]
Mean diameter	146±2 km[3] 128 km[4]
Mass	(4±1.6)×1018 kg[3] (6.62±0.84)×1018 kg[lower-alpha 1][6]
Mean density	2.4±1.0 g/cm3[3] 3.04±1.39 g/cm3[6]
Synodic rotation period	0.533 d (12.799 h)[1]
Geometric albedo	0.224 (calculated)[3] 0.243[1]
Spectral type	S[1]
Apparent magnitude	7.9[7] to 11.6
Absolute magnitude (H)	6.49[1]
Angular diameter	0.21" to 0.053"

Discovery and naming

Flora was discovered by J. R. Hind on 18 October 1847. It was his second asteroid discovery after 7 Iris.^{[citation needed]}

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), and mother of Spring. The Greek equivalent is Chloris, who has her own asteroid, 410 Chloris, but in Greek 8 Flora is also called 8 Chloris (8 Χλωρίς).^{[citation needed]} The old iconic symbol for 8 Flora has been variously rendered as , , etc.

Characteristics

Lightcurve analysis indicates that Flora's pole points towards ecliptic coordinates (β, λ) = (16°, 160°) with a 10° uncertainty.[5] 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.[10] This meteorite type comprises 35% of meteorites impacting the Earth.[11]

Observational mishap

During an observation on 25 March 1917, 8 Flora was mistaken for the 15th-magnitude star TU Leonis, which led to that star's classification as a U Geminorum cataclysmic variable star.[12] Flora had come to opposition on 1917 February 13, 40 days earlier.[12] This mistake was uncovered only in 1995.[12][13]

Occultation

On 26 July 2013, Flora at magnitude 8.8 occulted the star 2UCAC 22807162 over parts of South America, Africa, and Asia.[14]

Popular culture

In the 1968 science-fiction film The Green Slime, an orbital perturbation propels the asteroid Flora into a collision course with Earth.

Notes

References

External links

• shape model deduced from lightcurve
• "Announcement of discovery of Flora", MNRAS 8 (1848) 82
• 8 Flora at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 8 Flora at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

На других языках

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[de] (8) Flora

(8) Flora ist ein Asteroid des Asteroiden-Hauptgürtels, der am 18. Oktober 1847 von John Russell Hind am George-Bishop-Observatorium als achter Asteroid entdeckt wurde. Benannt wurde der Himmelskörper nach Flora, der römischen Göttin der Blüte und des Frühlings.

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- [en] 8 Flora

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[es] (8) Flora

(8) Flora es un asteroide perteneciente al cinturón de asteroides descubierto el 18 de octubre de 1847 por John Russell Hind desde el observatorio George Bishop de Londres, Reino Unido. Está nombrado por Flora, una diosa de la mitología romana.[2]

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[ru] (8) Флора

(8) Фло́ра (лат. Flora) — астероид главного пояса, который принадлежит к светлому спектральному классу S и возглавляет астероидное семейство Флоры. Он был открыт 18 октября 1847 г. английским астрономом Джоном Хиндом в обсерватории Бишопа, Великобритания, и назван в честь древнеримской богини цветов и весны Флоры[4].

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