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(85182) 1991 AQ, provisional designation 1991 AQ, is a stony asteroid on a highly eccentric orbit, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.1 kilometers (0.7 miles) in diameter. It was discovered on 14 January 1991, by American astronomer Eleanor Helin at the Palomar Observatory in California.[1] Based on its brightness variation of 0.69 magnitude, this Q-type asteroid is likely elongated.[4] It belongs to the small group of potentially hazardous asteroids larger than one kilometer.

(85182) 1991 AQ
Discovery [1]
Discovered byE. F. Helin
Discovery sitePalomar Obs.
Discovery date14 January 1991
Designations
MPC designation(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 arc26.91 yr (9,829 d)
Aphelion3.9474 AU
Perihelion0.4960 AU
2.2217 AU
Eccentricity0.7768
3.31 yr (1,210 d)
64.916°
0° 17m 51.36s / day
Inclination3.1276°
339.68°
242.96°
Earth MOID0.0165 AU (6.428 LD)
Physical characteristics
Mean diameter
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]

Contents

Orbit and classificationEdit

1991 AQ is a member of the Earth-crossing class of Apollo asteroids, the largest group of near-Earth objects with approximately 10 thousand known members.[1][2] It is also a Venus- and Mars-crosser due to its extreme perihelion 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 high eccentricity of 0.78 and an inclination of 3° with respect to the ecliptic.[2] The body's observation arc begins with its official discovery observation at Palomar in 1991.[1]

Close approachesEdit

The asteroid has currently an Earth minimum orbital intersection distance of 0.0165 AU (2,470,000 km; 1,530,000 mi), which corresponds to 6.4 lunar distances and makes it a potentially 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 to Mercury, Venus, Mars and Jupiter.[5]

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 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 15.30 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 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

Physical characteristicsEdit

In the Tholen classification, this object is an uncommon Q-type asteroid, that falls into the larger stony S-complex.[4] As of 2018, no rotational lightcurve of this asteroid has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.[2] It has a brightness variation of 0.69 magnitude, indicative for an elongated, non-spherical shape.[4]

Diameter and albedoEdit

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, this asteroid measures 1.1 kilometers in diameter and its surface has an albedo of 0.242.[3] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.18 and derives a diameter of 1.14 kilometers based on an absolute magnitude of 17.20.[4]

Numbering and namingEdit

This minor planet was numbered by the Minor Planet Center on 30 August 2004 (M.P.C. 52517).[6] As of 2018, it has not been named.[1]

ReferencesEdit

  1. ^ a b c d e f "85182 (1991 AQ)". Minor Planet Center. Retrieved 21 April 2018.
  2. ^ a b c d e f g h "JPL Small-Body Database Browser: 85182 (1991 AQ)" (2017-12-12 last obs.). Jet Propulsion Laboratory. Retrieved 21 April 2018.
  3. ^ a b c Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos" (PDF). The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. Retrieved 21 April 2018.
  4. ^ a b c d e f g h "LCDB Data for (85182)". Asteroid Lightcurve Database (LCDB). Retrieved 21 April 2018.
  5. ^ a b "JPL Small-Body Database Browser: 85182 (1991 AQ)". Jet Propulsion Laboratory. Retrieved 21 April 2018.
  6. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 21 April 2018.

External linksEdit