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5171 Augustesen, provisional designation 1987 SQ3, is a background asteroid and slow rotator from the inner regions of the asteroid belt, approximately 8 kilometers (5 miles) in diameter. It was discovered on 25 September 1987, by Danish astronomer Poul Jensen at the Brorfelde Observatory in Denmark.[1] The suspected tumbler and presumed Vestian asteroid has an exceptionally slow rotation period of 480 hours and possibly an elongated shape.[3] It was named after Danish astronomer Karl Augustesen.[1]

5171 Augustesen
Discovery [1]
Discovered byP. Jensen
Discovery siteBrorfelde Obs.
Discovery date25 September 1987
MPC designation(5171) Augustesen
Named after
Karl Augustesen[1]
(Danish astronomer)
1987 SQ3 · 1953 RP
1953 RP1 · 1989 CH8
main-belt · (inner)
background [2] · Vestian[3]
Orbital characteristics[4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc64.15 yr (23,430 d)
Aphelion2.7460 AU
Perihelion2.1036 AU
2.4248 AU
3.78 yr (1,379 d)
0° 15m 39.6s / day
Physical characteristics
Mean diameter
6.445±0.074 km[5]
6.81 km (calculated)[3]
9.02±2.21 km[6]
9.41±0.33 km[7]
9.73±2.59 km[8]
19.2±0.1 h (poor)[9]
480±10 h[10][a]
0.20 (assumed)[3]
X[11] · S[3]
13.10[5][8] · 13.20[3][7]
13.3[4] · 13.52[6]


Orbit and classificationEdit

Augustesen is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.[2] Based on osculating Keplerian orbital elements, the asteroid has also been classified as a member of the Vesta family (401), one of the main belt's largest asteroid families named after 4 Vesta, the family's parent body.[3]

It orbits the Sun in the inner main-belt at a distance of 2.1–2.7 AU once every 3 years and 9 months (1,379 days; semi-major axis of 2.42 AU). Its orbit has an eccentricity of 0.13 and an inclination of 7° with respect to the ecliptic.[4] The asteroid was first observed as 1953 RP and 1953 RP1 at Heidelberg and Goethe Link Observatory, where the body's observation arc begins in September 1953, or 34 years prior to its official discovery observation at Brorfelde.[1]

Physical characteristicsEdit

Augustesen has been characterized as an X-type asteroid by Pan-STARRS' photometric survey.[11] It is also an assumed S-type asteroid.[3]

Rotation periodEdit

In October 2006, a rotational lightcurve of Augustesen was obtained from photometric observations by Slovak astronomer Adrián Galád at Modra Observatory. Lightcurve analysis gave a long rotation period of 480 hours with a high brightness amplitude of 0.8 magnitude, indicative for a non-spherical shape (U=3).[10][a] The asteroid is a slow rotator with a period much longer than the typical 2 to 20 hours measured for most observed asteroids. Augustesen is also a suspected tumbler with a non-principal axis rotation, also known as "tumbling".[3]

An alternative measurement by Laurent Bernasconi gave a much shorter period based on a fragmentary (poor) lightcurve (U=1).[9]

Diameter and albedoEdit

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Augustesen measures between 6.445 and 9.73 kilometers in diameter and its surface has an albedo between 0.08 and 0.245.[5][6][7][8]

The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 6.81 kilometers based on an absolute magnitude of 13.2.[3]


This minor planet was named after Karl Augustesen (born 1945), a Danish astronomer and co-discoverer of minor planets. For several decades he had been an observer using the Schmidt telescope at the discovering Brorfelde Observatory in Denmark, after which the asteroid 3309 Brorfelde was named.[1]

The corrected official naming citation was published by the Minor Planet Center on 22 June 2005 (M.P.C. 54279).[12] In its preceding publication on 23 May 2005, the MPC erroneously named asteroid (6002) 1988 RO, which was discovered by Poul Jensen on 8 September 1988, as "6002 Augustesen" (M.P.C. 54173). As of 2018, the JPL SBDB still shows the (incorrect) discovery date of that other asteroid.[12]


  1. ^ a b Lightcurve plot of (5171) Augustesen (2006) Pravec/Galad. Rotation period 480 hours with a brightness amplitude of 0.8 mag. Quality code of 3. Summary figures at the LCDB and the Ondrejov Asteroid Photometry Project (data sheet).


  1. ^ a b c d e f "5171 Augustesen (1987 SQ3)". Minor Planet Center. Retrieved 26 March 2018.
  2. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 26 March 2018.
  3. ^ a b c d e f g h i j "LCDB Data for (5171) Augustesen". Asteroid Lightcurve Database (LCDB). Retrieved 26 March 2018.
  4. ^ a b c "JPL Small-Body Database Browser: 5171 Augustesen (1987 SQ3)" (2017-10-29 last obs.). Jet Propulsion Laboratory. Retrieved 26 March 2018.
  5. ^ a b c d Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 26 March 2018.
  6. ^ a b c d 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. Retrieved 26 March 2018.
  7. ^ a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 26 March 2018. Online catalog
  8. ^ a b c d 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. Retrieved 26 March 2018.
  9. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (5171) Augustesen". Geneva Observatory. Retrieved 26 March 2018.
  10. ^ a b Galád, Adrián; Pravec, Petr; Gajdos, Stefan; Kornos, Leonard; Világi, Jozef (October 2007). "Seven Asteroids Studied from Modra Observatory in the Course of Binary Asteroid Photometric Campaign". Earth. 101 (1–2): 17–25. Bibcode:2007EM&P..101...17G. doi:10.1007/s11038-007-9146-6. Retrieved 26 March 2018.
  11. ^ a b c 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. Retrieved 26 March 2018.
  12. ^ a b "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 26 March 2018.

External linksEdit