2062 Aten
Sub-kilometer asteroid
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2062 Aten /ˈɑːtən/,[a] provisional designation 1976 AA, is a stony sub-kilometer asteroid and namesake of the Aten asteroids, a subgroup of near-Earth objects. The asteroid was named after Aten from Egyptian mythology.
Orbit of Aten at epoch September 2013 | |
| Discovery[1][2] | |
|---|---|
| Discovered by | E. F. Helin |
| Discovery site | Palomar Obs. |
| Discovery date | 7 January 1976 |
| Designations | |
| Pronunciation | /ˈɑːtən/ |
Named after | Aten (Egyptian mythology)[3] |
| 1976 AA | |
| Aten · NEO[1][2] | |
| Symbol | .svg){kind=small} |
| Orbital characteristics[1] | |
| Epoch 31 December 2011 (JD 2455926.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 59.14 yr (21,601 days) |
| Earliest precovery date | 17 December 1955 |
| Aphelion | 1.1434 AU |
| Perihelion | 0.7901 AU |
| 0.9668 AU | |
| Eccentricity | 0.1827 |
| 0.95 yr (347 days) | |
| 172.27° | |
| 1° 2m 12.48s / day | |
| Inclination | 18.934° |
| 108.60° | |
| 148.04° | |
| Earth MOID | 0.1131 AU · 44.1 LD |
| Physical characteristics | |
| Dimensions | 0.73±0.03 km[4] 0.80±0.03 km[5] 0.91 km[6] 1.1 km[7] 1.30 km[8] |
| 40.77 h[9] | |
| 0.20[8] 0.20±0.15[10] 0.26[7] 0.28[6] 0.39±0.05[4] 0.52±0.10[5] | |
| S (Tholen)[1] · Sr (SMASS)[1] B–V = 0.930[1] U–B = 0.460[1] | |
| 16.80[1][5] · 17.01±1.40[11] · 17.12[9] · 17.20[12][6] · 17.30[4] | |
It was discovered on 7 January 1976, at the Palomar Observatory by American astronomer Eleanor Helin,[2] who was the principal scientist for the NEAT project until her retirement in 2002. The S-type asteroid measures approximately 900 meters in diameter, has a longer-than average rotation period of 44.77 hours, and approaches the orbit Earth to 44.1 lunar distances.
Orbit and classification
Aten orbits the Sun at a distance of 0.8–1.1 AU once every 11 months (347 days). Its orbit has an eccentricity of 0.18 and an inclination of 19° with respect to the ecliptic.[1] A first precovery was taken at the discovering observatory in December 1955, extending the body's observation arc by more than 20 years prior to its official discovery observation.[2]
Namesake of the Aten group
Aten was the first asteroid found to have a semi-major orbital axis of less than one astronomical unit and a period of less than one year.[3] A new category of asteroids was thus created, the Atens. As of 2017, the group consists of more than 1,200 numbered members. Other groups of near-Earth objects (NEOs) are the Apollo and Amor asteroids, which are both significantly larger than the Atens, while the Atira asteroids form the smallest NEO-group by far.[13]
Close approaches
The asteroid has an Earth minimum orbit intersection distance of 0.1131 AU (16,900,000 km) which corresponds to 44.1 lunar distances.[1]
Physical characteristics
In the Tholen classification, Aten is a common S-type asteroid. In the SMASS taxonomy it is classified as an Sr-type, a subtype which transitions to the R-type asteroids.[1]
Lightcurve
In the 1990s, Italian astronomer Stefano Mottola obtained a rotational lightcurve of Aten during the EUNEASO survey at La Silla, which was a European near-Earth object search and follow-up observation program to determine additional physical parameters. Lightcurve analysis gave a longer-than average rotation period of 40.77 hours with a brightness variation of 0.26 magnitude (U=2).[9] No additional lightcurves have been obtained since.[12]
Diameter and albedo
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Aten measures between 700 and 830 meters in diameter and its surface has a high albedo between 0.39 and 0.52.[4][5]
in 1994, Tom Gehrels published a diameter of 1.1 kilometers and an albedo of 0.26 in his book Hazards Due to Comets and Asteroids.[1][7] The Warm Spitzer NEO survey ("ExploreNEOs") gives a diameter of 1.3 kilometers with an albedo of 0.20.[8]
The Collaborative Asteroid Lightcurve Link agrees with a revised thermal model for asteroid diameters and albedos, and adopts an albedo of 0.28 with a diameter of 0.91 kilometers based on an absolute magnitude of 17.2.[6][12] However, the Minor Planet Center (MPC) classifies Aten as a larger (greater than 1 km) object.[2]
Naming
This minor planet was named from Egyptian mythology after Aten, the ancient Egyptian god of the solar disk, originally an aspect of the god Ra.[3] The official naming citation was published by the Minor Planet Center on 1 August 1978 (M.P.C. 4420).[14]
Notes
- Oxford English Dictionary