(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]

    (192642) 1999 RD32, provisional designation: 1999 RD32, is an asteroid and suspected contact binary on an eccentric orbit, classified as a large near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 5 kilometers (3 miles) 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]

    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 Toutatis2004-09-294.0314.0314.03115.32440–2450data
    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≈0.017 LD).
    (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. 1 2 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. 1 2 3 4 5 6 "JPL Small-Body Database Browser: 192642 (1999 RD32)" (2016-12-04 last obs.). Jet Propulsion Laboratory. Retrieved 16 January 2018.
    2. 1 2 "MPEC 1999-R32 : 1999 RD32". IAU Minor Planet Center. 11 September 1999. Retrieved 28 February 2014. (J99R32D)
    3. 1 2 3 4 5 "192642 (1999 RD32)". Minor Planet Center. Retrieved 16 January 2018.
    4. 1 2 3 4 5 6 "LCDB Data for (192642)". Asteroid Lightcurve Database (LCDB). Retrieved 16 January 2018.
    5. 1 2 3 4 5 6 "(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. 1 2 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. 1 2 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. 1 2 "JPL Close-Approach Data: 192642 (1999 RD32)" (2012-11-03 last obs and observation arc=17.8 years). Retrieved 28 February 2014.
    11. ↑ "1999RD32 Ephemerides for 25 August 1969 through 31 August 1969". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 28 February 2014.
    12. ↑ Michael Busch (12 March 2012). "Near-Earth Asteroids and Radar Speckle Tracking" (PDF). Retrieved 28 February 2014.
    13. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 24 February 2018.
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