(153591) 2001 SN263

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(153591) 2001 SN263
Discovery [1]
Discovered by LINEAR
Discovery site Lincoln Lab's ETS
Discovery date 20 September 2001
MPC designation (153591) 2001 SN263
2001 SN263
NEO · PHA[2] · Amor[1]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 25.18 yr (9,198 days)
Aphelion 2.9368 AU
Perihelion 1.0363 AU
1.9865 AU
Eccentricity 0.4783
2.80 yr (1,023 days)
0° 21m 7.2s / day
Inclination 6.6853°
Known satellites 2[3]
Earth MOID 0.0520 AU · 20.3 LD
Physical characteristics
Dimensions 2 km[3]
2.6 km[4]
2.63±0.40 km[5]
Mean density
1.3±0.6 g/cm³[4]
3.20±0.01 h[6]
3.423±0.001 h[a]
3.42510±0.00007 h[7]
3.4256±0.0002 h[8]
5.19±0.01 h[9]
C[6] · B[b]
16.81[10] · 16.9[1]

(153591) 2001 SN263 is a carbonaceous trinary[3] asteroid, classified as near-Earth object and former potentially hazardous asteroid of the Amor group, approximately 2.6 kilometers in diameter.

It was discovered by the Lincoln Near-Earth Asteroid Research project at Lincoln Lab's Experimental Test Site in Socorro, New Mexico, on 20 September 2001.[2]

The two minor-planet moons measure approximately 770 and 430 meters and have an orbital period of 16.46 and 150 hours, respectively.[8][10]


2001 SN263, the primary object of this trinary system, is an unusual carbonaceous near-Earth asteroid that orbits the Sun at a distance of 1.0–2.9 AU once every 2 years and 10 months (1,023 days). Its orbit has an eccentricity of 0.48 and an inclination of 7° with respect to the ecliptic.[1] A first precovery was taken at Palomar Observatory during the Digitized Sky Survey in 1990, extending the body's observation arc by 11 years prior to its official discovery observation at Socorro.[2]

It has an Earth minimum orbital intersection distance (MOID) of 0.0520 AU (7,780,000 km), which translates into 20.3 lunar distances.[1] With an Earth MOID above 0.05 AU, 2001 SN263 is no longer a potentially hazardous asteroid, despite being labelled as such by the MPC.[2]

According to various observations, 2001 SN263 measures between 2 and 2.63 kilometers in diameter, and its surface has a low albedo of 0.048,[3][4][5] A rotational lightcurve obtained from Photometric observation gave a rotation period of 3.20 to 5.19 hours with a brightness variation between 0.13 and 0.26 magnitude (U=2/3/3/2/n.a.).[6][7][8][9][a]

Trinay system[edit]

In 2008, scientists using the planetary radar at Arecibo Observatory discovered that the object is orbited by two satellites, when the triple asteroid made a close approach to Earth of 0.066 AU (nearly 10 million kilometers). The largest body is called Alpha and is spheroid in shape, with principal axes of 2.8±.1 km, 2.7±.1 km, and 2.5±.2 km and a density of nearly 1.3±0.6 g/cm3,[4] and the satellites, named Beta and Gamma, are several times smaller in size. Beta is 1.1 km in diameter and Gamma 0.4 km.

The only other unambiguously identified triple asteroid in the near-Earth population is (136617) 1994 CC, which was discovered to be a triple system in 2009.

Orbital characteristics of satellites[edit]

The orbital properties of the satellites are listed in this table.[11] The orbital planes of both satellites are inclined relative to each other; the relative inclination is about 14 degrees. Such a large inclination is suggestive of past evolutionary events (e.g. close encounter with a terrestrial planet, mean-motion-resonance crossing) that may have excited their orbits from a coplanar configuration to an inclined state.

Name Mass Semi-major axis Orbital period Eccentricity
Gamma (inner) ~10×1010 kg 3.8 km 0.686 days 0.016
Beta (outer) ~24×1010 kg 16.6 km 6.225 days 0.015


As of 2017, this minor planet and its moons remain unnamed.[2]


  1. ^ a b Warner (2011) web: photometric observations from 20 February 2008: rotation period 3.423±0.001 hours with a brightness amplitude of 0.14 magnitude. Quality code: 3. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (153591)
  2. ^ Perna (2014): photometric observation from 24 June 2011: with a brightness amplitude of mag. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (153591)


  1. ^ a b c d e f "JPL Small-Body Database Browser: 153591 (2001 SN263)" (2015-12-01 last obs.). Jet Propulsion Laboratory. Retrieved 1 June 2017. 
  2. ^ a b c d e "153591 (2001 SN263)". Minor Planet Center. Retrieved 22 March 2017. 
  3. ^ a b c d Nolan, M. C.; Howell, E. S.; Benner, L. A. M.; Ostro, S. J.; Giorgini, J. D.; Busch, M. W.; et al. (February 2008). "(153591) 2001 SN_263". Central Bureau Electronic Telegrams (1254). Bibcode:2008CBET.1254....1N. Retrieved 22 March 2017. 
  4. ^ a b c d Becker, Tracy; Howell, E. S.; Nolan, M. C.; Magri, C. (September 2008). "Physical Modeling of Triple Near-Earth Asteroid 153591 (2001 SN263)". American Astronomical Society. 40: 437. Bibcode:2008DPS....40.2806B. Retrieved 22 March 2017. 
  5. ^ a b c Delbo, Marco; Walsh, Kevin; Mueller, Michael; Harris, Alan W.; Howell, Ellen S. (March 2011). "The cool surfaces of binary near-Earth asteroids". Icarus. 212 (1): 138–148. Bibcode:2011Icar..212..138D. doi:10.1016/j.icarus.2010.12.011. Retrieved 22 March 2017. 
  6. ^ a b c Betzler, Alberto Silva; Novaes, Alberto Brum; Celedon, Julian Hermogenes Quesada (October 2008). "A Study of the Trinary NEA 2001 SN263". The Minor Planet Bulletin. 35 (4): 182–184. Bibcode:2008MPBu...35..182B. ISSN 1052-8091. Retrieved 22 March 2017. 
  7. ^ a b Oey, Julian (January 2009). "Lightcurve Analysis of Asteroids from Leura and Kingsgrove Observatories in the First Half of 2008". The Minor Planet Bulletin. 36 (1): 4–6. Bibcode:2009MPBu...36....4O. ISSN 1052-8091. Retrieved 22 March 2017. 
  8. ^ a b c Becker, Tracy M.; Howell, Ellen S.; Nolan, Michael C.; Magri, Christopher; Pravec, Petr; Taylor, Patrick A.; et al. (March 2015). "Physical modeling of triple near-Earth Asteroid (153591) 2001 SN263 from radar and optical light curve observations". Icarus. 248: 499–515. Bibcode:2015Icar..248..499B. doi:10.1016/j.icarus.2014.10.048. Retrieved 22 March 2017. 
  9. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (153591)". Geneva Observatory. Retrieved 22 March 2017. 
  10. ^ a b "LCDB Data for (153591)". Asteroid Lightcurve Database (LCDB). Retrieved 22 March 2017. 
  11. ^ Fang, Julia; Margot, Jean-Luc; Brozovic, Marina; Nolan, Michael C.; Benner, Lance A. M.; Taylor, Patrick A. (May 2011). "Orbits of Near-Earth Asteroid Triples 2001 SN263 and 1994 CC: Properties, Origin, and Evolution". The Astronomical Journal. 141 (5): 15. Bibcode:2011AJ....141..154F. arXiv:1012.2154Freely accessible. doi:10.1088/0004-6256/141/5/154. Retrieved 1 June 2017. 

External links[edit]