(192642) 1999 RD32

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(192642) 1999 RD32
1999rd32.jpg
Goldstone radar image showing the two lobes of suspected contact binary 1999 RD32.
Discovery [1][2][3]
Discovered by LINEAR
Discovery site Lincoln Lab's ETS
Discovery date 8 September 1999
Designations
MPC designation (192642) 1999 RD32
1999 RD32
Apollo · NEO · PHA[1][3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 21.92 yr (8,007 days)
Aphelion 4.6801 AU
Perihelion 0.6093 AU
2.6447 AU
Eccentricity 0.7696
4.30 yr (1,571 days)
89.009°
0° 13m 45.12s / day
Inclination 6.7914°
310.04°
299.89°
Earth MOID 0.0495 AU · 19.3 LD
Jupiter MOID 0.6702 AU
Physical characteristics
Mean diameter
1.63 km (calculated–dated)[4]
5 km (est.–radiometric)[5]
17.08±0.03 h[6][a]
17.1±0.5 h[7]
0.04 (est.–radiometric)[5]
0.20 (assumed–dated)[4]
C[4][5][8][9]
16.00[8] · 16.23±0.01[9] · 16.3[1][4]

(192642) 1999 RD32, provisional designation 1999 RD32, is an eccentric asteroid and suspected contact binary, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 5 kilometers in diameter. It was discovered on 8 September 1999, at a magnitude of 18, by astronomers of the LINEAR program using its 1-meter telescope at the Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, United States.[3][2] The asteroid is likely of carbonaceous composition and has a rotation period of 17.08 hours.[4][a]

Description[edit]

1999 RD32 orbits the Sun at a distance of 0.6–4.7 AU once every 4 years and 4 months (1,571 days; semi-major axis of 2.64 AU). Its orbit has a high eccentricity of 0.77 and an inclination of 7° with respect to the ecliptic.[1]

The asteroid's observation arc begins with a precovery taken at Palomar Observatory in January 1995.[3] It is known that 1999 RD32 passed 0.0093 AU (1,390,000 km; 860,000 mi) from Earth on 27 August 1969.[10] During the 1969 close approach the asteroid reached about apparent magnitude 8.8.[11] The similarly-sized 4179 Toutatis also reached that brightness in September 2004. It passed less than 0.007 AU (1,000,000 km; 650,000 mi) from asteroid 29 Amphitrite on 17 January 1939.[1]

Arecibo radar observations on 5–6 March 2012 showed that 1999 RD32 is approximately 5 kilometers (3 mi) in diameter[5] and has an estimated albedo of only 0.04.[5] Other sources calculate a smaller diameter of 1.63 kilometers based on a dated assumption, that the object is a stony rather than a carbonaceous asteroid.[4] The two visible lobes suggest that 1999 RD32 is a tight binary asteroid or contact binary.[5] About 10–15% of near-Earth asteroids larger than 200 meters are expected to be contact binary asteroids with two lobes in mutual contact.[12]

Close-approaches to Earth[10]
Date Distance from Earth
1969-08-27 0.0093 AU (1,390,000 km; 860,000 mi)
2012-03-14 0.1487 AU (22,250,000 km; 13,820,000 mi)
2042-03-11 0.1428 AU (21,360,000 km; 13,270,000 mi)
2046-09-04 0.1071 AU (16,020,000 km; 9,960,000 mi)

Notes[edit]

  1. ^ a b Lightcurve plot of (192642) 1999 RD32, Palmer Divide Observatory, B. D. Warner (2012): rotation period 17.08±0.03 hours with a brightness amplitude of 0.28±0.02 mag. Summary figures at the LCDB

References[edit]

  1. ^ a b c d e f "JPL Small-Body Database Browser: 192642 (1999 RD32)" (2016-12-04 last obs.). Jet Propulsion Laboratory. Retrieved 16 January 2018. 
  2. ^ a b "MPEC 1999-R32 : 1999 RD32". IAU Minor Planet Center. 1999-09-11. Retrieved 2014-02-28.  (J99R32D)
  3. ^ a b c d "192642 (1999 RD32)". Minor Planet Center. Retrieved 16 January 2018. 
  4. ^ a b c d e f "LCDB Data for (192642)". Asteroid Lightcurve Database (LCDB). Retrieved 16 January 2018. 
  5. ^ a b c d e f "(192642) 1999 RD32 Goldstone Radar Observations Planning". NASA/JPL Asteroid Radar Research. 12 March 2012. Retrieved 16 January 2018. 
  6. ^ Warner, Brian D.; Megna, Ralph (July 2012). "Lightcurve Analysis of NEA (192642) 1999 RD32". The Minor Planet Bulletin. 39 (3): 154. Bibcode:2012MPBu...39..154W. ISSN 1052-8091. Retrieved 16 January 2018. 
  7. ^ Vaduvescu, O.; Macias, A. Aznar; Tudor, V.; Predatu, M.; Galád, A.; Gajdos, S.; et al. (August 2017). "The EURONEAR Lightcurve Survey of Near Earth Asteroids". Earth. 120 (2): 41–100. Bibcode:2017EM&P..120...41V. doi:10.1007/s11038-017-9506-9. Retrieved 16 January 2018. 
  8. ^ a b Carry, B.; Solano, E.; Eggl, S.; DeMeo, F. E. (April 2016). "Spectral properties of near-Earth and Mars-crossing asteroids using Sloan photometry". Icarus. 268: 340–354. arXiv:1601.02087Freely accessible. Bibcode:2016Icar..268..340C. doi:10.1016/j.icarus.2015.12.047. Retrieved 16 January 2018. 
  9. ^ a b Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 16 January 2018. 
  10. ^ a b "JPL Close-Approach Data: 192642 (1999 RD32)" (2012-11-03 last obs and observation arc=17.8 years). Retrieved 2014-02-28. 
  11. ^ "1999RD32 Ephemerides for 25 August 1969 through 31 August 1969". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 2014-02-28. 
  12. ^ Michael Busch (2012-03-12). "Near-Earth Asteroids and Radar Speckle Tracking" (PDF). Retrieved 2014-02-28. 

External links[edit]