| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin |
| Discovery site | Palomar Obs. |
| Discovery date | 14 January 1991 |
| Designations | |
| (85182) 1991 AQ | |
| 1991 AQ · 1994 RD | |
| Apollo · NEO · PHA[1][2] | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 26.91yr (9,829 d) |
| Aphelion | 3.9474AU |
| Perihelion | 0.4960 AU |
| 2.2217 AU | |
| Eccentricity | 0.7768 |
| 3.31 yr (1,210 d) | |
| 64.916° | |
| 0° 17m 51.36s / day | |
| Inclination | 3.1276° |
| 339.68° | |
| 242.96° | |
| Earth MOID | 0.0165 AU (6.428LD) |
| Physical characteristics | |
| 1.1 km[3] 1.14 km(derived)[4] | |
| 0.18(assumed)[4] 0.242±0.194[3] | |
| Q(Tholen)[4] | |
| 17.1[2] 17.20[4] | |
(85182) 1991 AQ (provisional designation1991 AQ) is a stonyasteroid on a highly eccentric orbit, classified asnear-Earth object andpotentially hazardous asteroid of theApollo group, approximately 1.1 kilometers (0.7 miles) in diameter. It was discovered on 14 January 1991, by American astronomerEleanor Helin at thePalomar Observatory in California.[1] Based on its brightness variation of 0.69magnitude, thisQ-type asteroid is likely elongated.[4] It belongs to the small group of potentially hazardous asteroids larger than one kilometer.
1991 AQ is a member of theEarth-crossing class ofApollo asteroids, the largest group ofnear-Earth objects with approximately 10 thousand known members.[1][2] It is also aVenus- andMars-crosser due to its extremeperihelion and aphelion, respectively.[2]
It orbits the Sun at a distance of 0.5–3.9 AU once every 3 years and 4 months (1,210 days;semi-major axis of 2.22 AU). Its orbit has a higheccentricity of 0.78 and aninclination of 3° with respect to theecliptic.[2] The body'sobservation arc begins with its official discovery observation at Palomar in 1991.[1]
The asteroid has currently an Earthminimum orbital intersection distance of 0.0165 AU (2,470,000 km; 1,530,000 mi), which corresponds to 6.4lunar distances and makes it apotentially hazardous asteroid due to its notably large size.[2] In 1991 and 1994, it approached Earth at a nominal distance of 0.054 AU (21 LD). The asteroids closest encounter with Earth is projected to occur on 27 January 2130, at a distance of 0.0106 AU (4.1 LD) only(see table).[5] It also makes close encounters toMercury,Venus,Mars andJupiter.[5]
| PHA | Date | Approach distance (lunar dist.) | Abs. mag (H) | Diameter (C) (m) | Ref (D) | ||
|---|---|---|---|---|---|---|---|
| Nomi- nal(B) | Mini- mum | Maxi- mum | |||||
| (33342) 1998 WT24 | 1908-12-16 | 3.542 | 3.537 | 3.547 | 17.9 | 556–1795 | data |
| (458732) 2011 MD5 | 1918-09-17 | 0.911 | 0.909 | 0.913 | 17.9 | 556–1795 | data |
| (7482) 1994 PC1 | 1933-01-17 | 2.927 | 2.927 | 2.928 | 16.8 | 749–1357 | data |
| 69230 Hermes | 1937-10-30 | 1.926 | 1.926 | 1.927 | 17.5 | 668–2158 | data |
| 69230 Hermes | 1942-04-26 | 1.651 | 1.651 | 1.651 | 17.5 | 668–2158 | data |
| (137108) 1999 AN10 | 1946-08-07 | 2.432 | 2.429 | 2.435 | 17.9 | 556–1795 | data |
| (33342) 1998 WT24 | 1956-12-16 | 3.523 | 3.523 | 3.523 | 17.9 | 556–1795 | data |
| (163243) 2002 FB3 | 1961-04-12 | 4.903 | 4.900 | 4.906 | 16.4 | 1669–1695 | data |
| (192642) 1999 RD32 | 1969-08-27 | 3.627 | 3.625 | 3.630 | 16.3 | 1161–3750 | data |
| (143651) 2003 QO104 | 1981-05-18 | 2.761 | 2.760 | 2.761 | 16.0 | 1333–4306 | data |
| 2017 CH1 | 1992-06-05 | 4.691 | 3.391 | 6.037 | 17.9 | 556–1795 | data |
| (170086) 2002 XR14 | 1995-06-24 | 4.259 | 4.259 | 4.260 | 18.0 | 531–1714 | data |
| (33342) 1998 WT24 | 2001-12-16 | 4.859 | 4.859 | 4.859 | 17.9 | 556–1795 | data |
| 4179 Toutatis | 2004-09-29 | 4.031 | 4.031 | 4.031 | 15.3 | 2440–2450 | data |
| 2014 JO25 | 2017-04-19 | 4.573 | 4.573 | 4.573 | 17.8 | 582–1879 | data |
| (137108) 1999 AN10 | 2027-08-07 | 1.014 | 1.010 | 1.019 | 17.9 | 556–1795 | data |
| (35396) 1997 XF11 | 2028-10-26 | 2.417 | 2.417 | 2.418 | 16.9 | 881–2845 | data |
| (154276) 2002 SY50 | 2071-10-30 | 3.415 | 3.412 | 3.418 | 17.6 | 714–1406 | data |
| (164121) 2003 YT1 | 2073-04-29 | 4.409 | 4.409 | 4.409 | 16.2 | 1167–2267 | data |
| (385343) 2002 LV | 2076-08-04 | 4.184 | 4.183 | 4.185 | 16.6 | 1011–3266 | data |
| (52768) 1998 OR2 | 2079-04-16 | 4.611 | 4.611 | 4.612 | 15.8 | 1462–4721 | data |
| (33342) 1998 WT24 | 2099-12-18 | 4.919 | 4.919 | 4.919 | 17.9 | 556–1795 | 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 | 668–2158 | data |
| (137126) 1999 CF9 | 2192-08-21 | 4.970 | 4.967 | 4.973 | 18.0 | 531–1714 | data |
| (290772) 2005 VC | 2198-05-05 | 1.951 | 1.791 | 2.134 | 17.6 | 638–2061 | data |
| (A) List includes near-Earth approaches of less than 5lunar distances (LD) of objects withH 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 onH andalbedo range between X and Y. (D) Reference: data source from theJPL SBDB, withAU converted into LD (1 AU≈390 LD) (E) Color codes: unobserved at close approach observed during close approach upcoming approaches | |||||||
In theTholen classification, this object is an uncommonQ-type asteroid, that falls into the larger stonyS-complex.[4] As of 2018, no rotationallightcurve of this asteroid has been obtained fromphotometric observations. The body'srotation period,pole and shape remain unknown.[2] It has a brightness variation of 0.69magnitude, indicative for an elongated, non-spherical shape.[4]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer, this asteroid measures 1.1 kilometers in diameter and its surface has analbedo of 0.242.[3] TheCollaborative Asteroid Lightcurve Link assumes an albedo of 0.18 and derives a diameter of 1.14 kilometers based on anabsolute magnitude of 17.20.[4]
Thisminor planet wasnumbered by theMinor Planet Center on 30 August 2004 (M.P.C. 52517).[6] As of 2018, it has not beennamed.[1]
