(192642) 1999 RD32

(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][lower-alpha 1]

(192642) 1999 RD32
Goldstone radar image showing the two lobes of suspected contact binary 1999 RD32.
Discovery [1][2][3]
Discovered byLINEAR
Discovery siteLincoln Lab's ETS
Discovery date8 September 1999
Designations
(192642) 1999 RD32
1999 RD32
Apollo · NEO · PHA [1][3]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc21.92 yr (8,007 days)
Aphelion4.6801 AU
Perihelion0.6093 AU
2.6447 AU
Eccentricity0.7696
4.30 yr (1,571 days)
89.009°
0° 13m 45.12s / day
Inclination6.7914°
310.04°
299.89°
Earth MOID0.0495 AU · 19.3 LD
Jupiter MOID0.6702 AU
Physical characteristics
Mean diameter
1.63 km (calculated–dated)[4]
5 km (est.–radiometric)[5]
17.08±0.03 h[6][lower-alpha 1]
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]

    Description

    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]
    DateDistance from Earth
    1969-08-270.0093 AU (1,390,000 km; 860,000 mi)
    2012-03-140.1487 AU (22,250,000 km; 13,820,000 mi)
    2042-03-110.1428 AU (21,360,000 km; 13,270,000 mi)
    2046-09-040.1071 AU (16,020,000 km; 9,960,000 mi)
    History of close approaches of large near-Earth objects since 1908 (A)
    PHA Date Approach distance (lunar dist.) Abs.
    mag
    (H)    		 Diameter (C)
    (m)    		 Ref (D)
    Nomi-
    nal(B)    		 Mini-
    mum    		 Maxi-
    mum
    (33342) 1998 WT241908-12-163.5423.5373.54717.9556–1795data
    (458732) 2011 MD51918-09-170.9110.9090.91317.9556–1795data
    (7482) 1994 PC11933-01-172.9272.9272.92816.8749–1357data
    69230 Hermes1937-10-301.9261.9261.92717.5668–2158data
    69230 Hermes1942-04-261.6511.6511.65117.5668–2158data
    (137108) 1999 AN101946-08-072.4322.4292.43517.9556–1795data
    (33342) 1998 WT241956-12-163.5233.5233.52317.9556–1795data
    (163243) 2002 FB31961-04-124.9034.9004.90616.41669–1695data
    (192642) 1999 RD321969-08-273.6273.6253.63016.31161–3750data
    (143651) 2003 QO1041981-05-182.7612.7602.76116.01333–4306data
    2017 CH11992-06-054.6913.3916.03717.9556–1795data
    (170086) 2002 XR141995-06-244.2594.2594.26018.0531–1714data
    (33342) 1998 WT242001-12-164.8594.8594.85917.9556–1795data
    4179 Toutatis2004-09-294.0314.0314.03115.302440–2450data
    2014 JO252017-04-194.5734.5734.57317.8582–1879data
    (137108) 1999 AN102027-08-071.0141.0101.01917.9556–1795data
    (35396) 1997 XF112028-10-262.4172.4172.41816.9881–2845data
    (154276) 2002 SY502071-10-303.4153.4123.41817.6714–1406data
    (164121) 2003 YT12073-04-294.4094.4094.40916.21167–2267data
    (385343) 2002 LV2076-08-044.1844.1834.18516.61011–3266data
    (52768) 1998 OR22079-04-164.6114.6114.61215.81462–4721data
    (33342) 1998 WT242099-12-184.9194.9194.91917.9556–1795data
    (85182) 1991 AQ2130-01-274.1404.1394.14117.11100data
    314082 Dryope2186-07-163.7092.9964.78617.5668–2158data
    (137126) 1999 CF92192-08-214.9704.9674.97318.0531–1714data
    (290772) 2005 VC2198-05-051.9511.7912.13417.6638–2061data
    (A) List includes near-Earth approaches of less than 5 lunar distances (LD) of objects with H brighter than 18.
    (B) Nominal geocentric distance from the Earth's center to the object's center (earth radius≈6400 km).
    (C) Diameter: estimated, theoretical mean-diameter based on H and albedo range between X and Y.
    (D) Reference: data source from the JPL SBDB, with AU converted into LD (1 AU≈390 LD)
    (E) Color codes:   unobserved at close approach   observed during close approach   upcoming approaches

    Numbering and naming

    This minor planet was numbered by the Minor Planet Center on 13 November 2008.[13] As of 2018, it has not been named.[3]

    Notes
    1. 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
    1. "JPL Small-Body Database Browser: 192642 (1999 RD32)" (2016-12-04 last obs.). Jet Propulsion Laboratory. Retrieved 16 January 2018.
    2. "MPEC 1999-R32 : 1999 RD32". IAU Minor Planet Center. 1999-09-11. Retrieved 2014-02-28. (J99R32D)
    3. "192642 (1999 RD32)". Minor Planet Center. Retrieved 16 January 2018.
    4. "LCDB Data for (192642)". Asteroid Lightcurve Database (LCDB). Retrieved 16 January 2018.
    5. "(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. hdl:10316/80202. Retrieved 16 January 2018.
    8. 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:1601.02087. Bibcode:2016Icar..268..340C. doi:10.1016/j.icarus.2015.12.047. Retrieved 16 January 2018.
    9. 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:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 16 January 2018.
    10. "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.
    13. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 24 February 2018.
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