(192642) 1999 RD32
Asteroid and suspected contact binary
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(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][a]
_1999_RD32.jpg)
| |
| Discovery[1][2][3] | |
|---|---|
| Discovered by | LINEAR |
| Discovery site | Lincoln Lab's ETS |
| Discovery date | 8 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 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 | |
| 1.63 km (calculatedâdated)[4] 5 km (est.âradiometric)[5] | |
| 17.08±0.03 h[6][a] 17.1±0.5 h[7] | |
| 0.04 (est.âradiometric)[5] 0.20 (assumedâdated)[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 0.6â4.7 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 5â6 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 10â15% of near-Earth asteroids larger than 200 meters are expected to be contact binary asteroids with two lobes in mutual contact.[12]
| PHA | Date | Approach distance (lunar dist.) | Abs. mag (H) |
Diameterâ(C) (m) |
Refâ(D) | ||
|---|---|---|---|---|---|---|---|
| Nomi- nal(B) |
Mini- mum |
Maxi- mum | |||||
| (33342) 1998 WT24 | 1908-12-16 | 3.542 | 3.537 | 3.547 | 17.9 | 556â1795 | data |
| (458732) 2011 MD5 | 1918-09-17 | 0.911 | 0.909 | 0.913 | 17.9 | 556â1795 | data |
| (7482) 1994 PC1 | 1933-01-17 | 2.927 | 2.927 | 2.928 | 16.8 | 749â1357 | data |
| 69230 Hermes | 1937-10-30 | 1.926 | 1.926 | 1.927 | 17.5 | 668â2158 | data |
| 69230 Hermes | 1942-04-26 | 1.651 | 1.651 | 1.651 | 17.5 | 668â2158 | data |
| (137108) 1999 AN10 | 1946-08-07 | 2.432 | 2.429 | 2.435 | 17.9 | 556â1795 | data |
| (33342) 1998 WT24 | 1956-12-16 | 3.523 | 3.523 | 3.523 | 17.9 | 556â1795 | data |
| (163243) 2002 FB3 | 1961-04-12 | 4.903 | 4.900 | 4.906 | 16.4 | 1669â1695 | data |
| (192642) 1999 RD32 | 1969-08-27 | 3.627 | 3.625 | 3.630 | 16.3 | 1161â3750 | data |
| (143651) 2003 QO104 | 1981-05-18 | 2.761 | 2.760 | 2.761 | 16.0 | 1333â4306 | data |
| 2017 CH1 | 1992-06-05 | 4.691 | 3.391 | 6.037 | 17.9 | 556â1795 | data |
| (170086) 2002 XR14 | 1995-06-24 | 4.259 | 4.259 | 4.260 | 18.0 | 531â1714 | data |
| (33342) 1998 WT24 | 2001-12-16 | 4.859 | 4.859 | 4.859 | 17.9 | 556â1795 | data |
| 4179 Toutatis | 2004-09-29 | 4.031 | 4.031 | 4.031 | 15.3 | 2440â2450 | data |
| (671294)2014 JO25 | 2017-04-19 | 4.573 | 4.573 | 4.573 | 17.8 | 582â1879 | data |
| (137108) 1999 AN10 | 2027-08-07 | 1.014 | 1.010 | 1.019 | 17.9 | 556â1795 | data |
| (35396) 1997 XF11 | 2028-10-26 | 2.417 | 2.417 | 2.418 | 16.9 | 881â2845 | data |
| (154276) 2002 SY50 | 2071-10-30 | 3.415 | 3.412 | 3.418 | 17.6 | 714â1406 | data |
| (164121) 2003 YT1 | 2073-04-29 | 4.409 | 4.409 | 4.409 | 16.2 | 1167â2267 | data |
| (385343) 2002 LV | 2076-08-04 | 4.184 | 4.183 | 4.185 | 16.6 | 1011â3266 | data |
| (52768) 1998 OR2 | 2079-04-16 | 4.611 | 4.611 | 4.612 | 15.8 | 1462â4721 | data |
| (33342) 1998 WT24 | 2099-12-18 | 4.919 | 4.919 | 4.919 | 17.9 | 556â1795 | data |
| (85182) 1991 AQ | 2130-01-27 | 4.140 | 4.139 | 4.141 | 17.1 | 1100 | data |
| 314082 Dryope | 2186-07-16 | 3.709 | 2.996 | 4.786 | 17.5 | 668â2158 | data |
| (137126) 1999 CF9 | 2192-08-21 | 4.970 | 4.967 | 4.973 | 18.0 | 531â1714 | data |
| (290772) 2005 VC | 2198-05-05 | 1.951 | 1.791 | 2.134 | 17.6 | 638â2061 | data |
| (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 radiusâ0.017 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 AUâ390 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
- 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