2062 Aten

2062 Aten

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
MPC designation	(2062) Aten
Pronunciation	/ˈɑːtən/
Named after	Aten (Egyptian mythology)[3]
Alternative designations	1976 AA
Minor planet category	Aten · NEO [1][2]
Symbol
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
Semi-major axis	0.9668 AU
Eccentricity	0.1827
Orbital period (sidereal)	0.95 yr (347 days)
Mean anomaly	172.27°
Mean motion	1° 2^m 12.48^s / day
Inclination	18.934°
Longitude of ascending node	108.60°
Argument of perihelion	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]
Synodic rotation period	40.77 h[9]
Geometric albedo	0.20[8] 0.20±0.15[10] 0.26[7] 0.28[6] 0.39±0.05[4] 0.52±0.10[5]
Spectral type	S (Tholen)[1] · Sr (SMASS)[1] B–V = 0.930[1] U–B = 0.460[1]
Absolute magnitude (H)	16.80[1][5] · 17.01±1.40[11] · 17.12[9] · 17.20[12][6] · 17.30[4]

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.

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 "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

1. Oxford English Dictionary

References

1. "JPL Small-Body Database Browser: 2062 Aten (1976 AA)" (2015-02-06 last obs.). Jet Propulsion Laboratory. Archived from the original on 25 January 2020. Retrieved 3 August 2017.
2. "2062 Aten (1976 AA)". Minor Planet Center. Retrieved 3 August 2017.
3. Schmadel, Lutz D. (2007). "(2062) Aten". Dictionary of Minor Planet Names – (2062) Aten. Springer Berlin Heidelberg. p. 167. doi:10.1007/978-3-540-29925-7_2063. ISBN 978-3-540-00238-3.
4. Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63.
5. 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". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. S2CID 9341381.
6. Harris, Alan W. (February 1998). "A Thermal Model for Near-Earth Asteroids". Icarus. 131 (2): 291–301. Bibcode:1998Icar..131..291H. doi:10.1006/icar.1997.5865.
7. Tom Gehrels; Mildred Shapley Matthews; A. M. Schumann (1994). Hazards Due to Comets and Asteroids. University of Arizona Press. pp. 540–543. ISBN 978-0-8165-1505-9.
8. Harris, A. W.; Mommert, M.; Hora, J. L.; Mueller, M.; Trilling, D. E.; Bhattacharya, B.; et al. (March 2011). "ExploreNEOs. II. The Accuracy of the Warm Spitzer Near-Earth Object Survey" (PDF). The Astronomical Journal. 141 (3): 10. Bibcode:2011AJ....141...75H. doi:10.1088/0004-6256/141/3/75. S2CID 14208889.
9. Mottola, S.; de Angelis, G.; di Martino, M.; Erikson, A.; Harris, A. W.; Hahn, G.; et al. (March 1995). "The EUNEASO Photometric Follow-up Program". Abstracts of the Lunar and Planetary Science Conference. 26: 1003. Bibcode:1995LPI....26.1003M.
10. Thomas, C. A.; Trilling, D. E.; Emery, J. P.; Mueller, M.; Hora, J. L.; Benner, L. A. M.; et al. (September 2011). "ExploreNEOs. V. Average Albedo by Taxonomic Complex in the Near-Earth Asteroid Population". The Astronomical Journal. 142 (3): 12. Bibcode:2011AJ....142...85T. doi:10.1088/0004-6256/142/3/85.
11. 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. S2CID 53493339.
12. "LCDB Data for (2062) Aten". Asteroid Lightcurve Database (LCDB). Retrieved 3 August 2017.
13. "Discovery Statistics". CNEOS / JPL. Retrieved 3 August 2017.
14. Schmadel, Lutz D. (2009). "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. Bibcode:2009dmpn.book.....S. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.