Astronomy:2062 Aten

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Short description: Sub-kilometer asteroid
2062 Aten 24px
Aten Sept 11 2013.png
Orbit of Aten at epoch September 2013
Discovery [1][2]
Discovered byE. F. Helin
Discovery sitePalomar Obs.
Discovery date7 January 1976
Designations
(2062) Aten
Pronunciation/ˈɑːtən/
Named afterAten (Egyptian mythology)[3]
1976 AA
Minor planet categoryAten · NEO [1][2]
Orbital characteristics [1]
Epoch 31 December 2011 (JD 2455926.5)
Uncertainty parameter 0
Observation arc59.14 yr (21,601 days)
Earliest precovery date17 December 1955
|{{{apsis}}}|helion}}1.1434 AU
|{{{apsis}}}|helion}}0.7901 AU
0.9668 AU
Eccentricity0.1827
Orbital period0.95 yr (347 days)
Mean anomaly172.27°
Mean motion1° 2m 12.48s / day
Inclination18.934°
Longitude of ascending node108.60°
148.04°
Earth MOID0.1131 AU · 44.1 LD
Physical characteristics
Dimensions0.73±0.03 km[4]
0.80±0.03 km[5]
0.91 km[6]
1.1 km[7]
1.30 km[8]
Rotation period40.77 h[9]
Geometric albedo0.20[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]
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/,[lower-alpha 1] 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 ({{{1}}}).[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. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 "JPL Small-Body Database Browser: 2062 Aten (1976 AA)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2002062. Retrieved 3 August 2017. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 "2062 Aten (1976 AA)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=2062. Retrieved 3 August 2017. 
  3. ↑ 3.0 3.1 3.2 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. ↑ 4.0 4.1 4.2 4.3 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. doi:10.3847/0004-6256/152/3/63. Bibcode: 2016AJ....152...63N. 
  5. ↑ 5.0 5.1 5.2 5.3 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. doi:10.1088/0004-637X/814/2/117. Bibcode: 2015ApJ...814..117N. 
  6. ↑ 6.0 6.1 6.2 6.3 Harris, Alan W. (February 1998). "A Thermal Model for Near-Earth Asteroids". Icarus 131 (2): 291–301. doi:10.1006/icar.1997.5865. Bibcode: 1998Icar..131..291H. 
  7. ↑ 7.0 7.1 7.2 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. https://books.google.com/books?id=zpfvAAAAMAAJ. 
  8. ↑ 8.0 8.1 8.2 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". The Astronomical Journal 141 (3): 10. doi:10.1088/0004-6256/141/3/75. Bibcode: 2011AJ....141...75H. https://authors.library.caltech.edu/22857/1/Harris2011p13012Astron_J.pdf. 
  9. ↑ 9.0 9.1 9.2 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. doi:10.1088/0004-6256/142/3/85. Bibcode: 2011AJ....142...85T. 
  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. doi:10.1016/j.icarus.2015.08.007. Bibcode: 2015Icar..261...34V. 
  12. ↑ 12.0 12.1 12.2 "LCDB Data for (2062) Aten". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=2062%7CAten. Retrieved 3 August 2017. 
  13. ↑ "Discovery Statistics". CNEOS / JPL. https://cneos.jpl.nasa.gov/stats/totals.html. 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. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7. Bibcode: 2009dmpn.book.....S. https://archive.org/details/dictionaryminorp2008schm. 

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