3122 Florence

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3122 Florence
SMASS = S [1][7] · Sq [19]
13.87±0.1 (R)[a] · 14.0[9] · 14.04±0.1 (R)[a] · 14.1[1] · 14.515±0.11[6][7] · 14.65±0.11[16] · 14.65±0.3[5]

3122 Florence is a stony

potentially hazardous asteroid. It measures approximately 5 kilometers in diameter. It orbits the Sun at a distance of 1.0–2.5 AU once every 2 years and 4 months (859 days); the orbit has an eccentricity of 0.42 and an inclination of 22° with respect to the ecliptic.[1] Florence has two moons
.

Florence was discovered on 2 March 1981 by American astronomer Schelte J. "Bobby" Bus at Siding Spring Observatory.[4] Its provisional designation was 1981 ET3. It was named in honor of Florence Nightingale, the founder of modern nursing;[3] the naming citation was published on 6 April 1993 (M.P.C. 21955).[21]

Florence is classified as a potentially hazardous object because its minimum orbit intersection distance (MOID ≤ 0.05 AU) indicates that it has the potential to make close approaches to the Earth, and because measurements of its absolute magnitude (H ≤ 22) suggest that it is large enough to create serious damage were it to impact.[1][22]

Moons

Trinary asteroid: Florence with its two satellites

Radar observations during the 2017 flyby have shown that Florence has two moons. The inner of the two moons is estimated to have a diameter of 180 to 240 meters, the outer moon is between 300 and 360 meters across. Each moon is somewhat elongated, and both are tidally locked to the main body. They probably formed as loose material spun away from the main body as its rotation accelerated due to the YORP effect.[10]

The inner moon's period orbiting Florence appears to be approximately 7 hours, while the outer moon completes a revolution in about 21 to 23 hours. The inner moon of Florence has the shortest orbital period of any of the moons of the 60 near-Earth asteroids known to have moons.[10]

Florence is only the third known trinary asteroid in the near-Earth asteroid population, after (153591) 2001 SN263 and (136617) 1994 CC.

2017 close approach

On 1 September 2017, Florence passed 0.047237 AU (7,066,600 km; 4,391,000 mi) from Earth, approximately eighteen times the average distance of the Moon.[23] As seen from Earth, it brightened to apparent magnitude 8.5, and was visible in small telescopes for several nights as it moved south to north through the constellations Piscis Austrinus, Capricornus, Aquarius, and Delphinus.[24] This was the asteroid's closest approach since 1890 and the closest until after 2500.[25][26][27] Its previous flyby was on 29 August 1930, at a distance of 0.05239 AU and the next one will be on 2 September 2057, at 0.049952 AU.[28]

  • Animation: 2017-08-30 21:48:46 to 22:53:00 UTC
    Animation: 2017-08-30 21:48:46 to 22:53:00 UTC
  • 3122 Florence passing the Earth in 2017
    3122 Florence passing the Earth in 2017
  • Orbit of Florence
    Orbit of Florence
  • Daily motion of 3122 Florence as seen from earth near 1 September 2017 flyby.
    Daily motion of 3122 Florence as seen from earth near 1 September 2017 flyby.

Radar imagery

During the flyby, scientists studied Florence using the Arecibo Observatory and the Goldstone Deep Space Communications Complex, and discovered that it has two moons.[20][29]

Goldstone Radar
Arecibo Radar

Notes

  1. ^ a b c Pravec (2002/2003) web: rotation period 2.3581±0.0001 hours with a brightness amplitude of 0.15 and 0.18 mag, respectively. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (3122) Florence and Pravec, P.; Wolf, M.; Sarounova, L. (2002)

References

  1. ^ a b c d e f g h "JPL Small-Body Database Browser: 3122 Florence (1981 ET3)" (2016-05-28 last obs.). Jet Propulsion Laboratory. Retrieved 7 January 2017.
  2. ^ "Florence". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 23 March 2020.
  3. ^
    ISBN 978-3-540-00238-3
    .
  4. ^ a b "3122 Florence (1981 ET3)". Minor Planet Center. Retrieved 7 January 2017.
  5. ^
    S2CID 41459166
    . Retrieved 7 January 2017.
  6. ^
    doi:10.1016/j.icarus.2012.07.026
    . Retrieved 7 January 2017.
  7. ^ a b c "LCDB Data for (3122) Florence". Asteroid Lightcurve Database (LCDB). Retrieved 7 January 2017.
  8. ^ "(3122) Florence". The Near-Earth Asteroids Data Base at E.A.R.N. Archived from the original on 12 August 2012. Retrieved 30 August 2017.
  9. ^
    S2CID 35447010
    .
  10. ^ a b c d e "Telescopes Worldwide Collaborate to Observe Asteroid Florence During its Recent Close Approach to Earth". Jet Propulsion Laboratory. 11 September 2017. Retrieved 14 September 2017.
  11. PMID 32539024
    . Retrieved 7 January 2017.
  12. doi:10.1006/icar.1998.5993
    . Retrieved 7 January 2017.
  13. ^ Behrend, Raoul. "Asteroids and comets rotation curves – (3122) Florence". Geneva Observatory. Retrieved 7 January 2017.
  14. ISSN 1052-8091
    . Retrieved 7 January 2017.
  15. ISSN 1052-8091
    . Retrieved 7 January 2017.
  16. ^
    Bibcode:1995LPI....26.1511W
    . Retrieved 7 January 2017.
  17. doi:10.1088/0004-6256/142/3/85
    .
  18. S2CID 239991
    . Retrieved 7 January 2017.
  19. S2CID 119278697
    . Retrieved 7 January 2017.
  20. ^ a b c "Radar Reveals Two Moons Orbiting Asteroid Florence". Jet Propulsion Laboratory. 1 September 2017. Retrieved 14 September 2017.
  21. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 7 January 2017.
  22. ^ "NEO Groups". Near Earth Object Program. NASA. Archived from the original on 2 November 2016.
  23. ^ "JPL Close-Approach Data: 3122 Florence (1981 ET3)" (2017-08-30 last obs). Retrieved 30 August 2017.
  24. ^ "Asteroid Besar dan Langka Lintasi Langit Indonesia Malam Ini". detik.com. 1 September 2017. Retrieved 5 September 2021.
  25. ^ PTI (18 August 2017). "Nasa says big asteroid to pass safely by Earth on 1 September". Livemint.
  26. ^ "Asteroid Florence Pays Earth a Visit – Sky & Telescope". 30 August 2017. Retrieved 1 September 2017.
  27. ^ "See Florence, One Of The Largest Near-Earth Asteroids, Zip By Earth". 30 August 2017. Retrieved 1 September 2017.
  28. ^ a b "Goldstone Radar Observations Planning: Asteroid 3122 Florence and 2001 QL142". NASA. 29 August 2017.
  29. ^ a b "Arecibo announces two moons (September 2nd)". Twitter. 2 September 2017.
  30. ^ "Arecibo imagery from September 2nd (5x higher resolution)". Twitter. 2 September 2017.
  31. ^ "Arecibo reveals surface features of 3122 Florence". Twitter. 3 September 2017.
  32. ^ "One full rotation of 3122 Florence, as seen from Arecibo". Twitter. 4 September 2017.
  33. ^ "Last images of 3122 Florence from Arecibo". Twitter. 5 September 2017.

External links

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