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1651 Behrens, provisional designation 1936 HD, is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 10 kilometers in diameter. Discovered by Marguerite Laugier in 1936, it was named after Johann Behrens.

1651 Behrens
Discovery [1]
Discovered byM. Laugier
Discovery siteNice Obs.
Discovery date23 April 1936
MPC designation(1651) Behrens
Named after
Johann Behrens
(pastor, astronomer)[2]
1936 HD · 1939 EJ
1940 QD · 1944 YA
1947 WA · 1950 TB4
1952 FF · 1952 HB
1952 KG · 1958 BC
1961 AB · 1963 UQ
main-belt · Flora[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc81.03 yr (29,597 days)
Aphelion2.3237 AU
Perihelion2.0354 AU
2.1796 AU
3.22 yr (1,175 days)
0° 18m 22.68s / day
Physical characteristics
9.264±0.080 km[5]
10.25±2.24 km[6]
10.31 km (calculated)[3]
10.33±2.35 km[7]
34.34±0.10 h[8]
0.24 (assumed)[3]
12.1[1][3][5][6] · 12.17±0.20[9] · 12.56[7]



Behrens was discovered on 23 April 1936, by French astronomer Marguerite Laugier at Nice Observatory in southeastern France.[10] It was independently discovered by Karl Reinmuth at Heidelberg Observatory, Germany in the following month.[2]

Classification and orbitEdit

Behrens is an S-type asteroid and member of the Flora family, a large group of stony asteroids in the inner main-belt. It orbits the Sun at a distance of 2.0–2.3 AU once every 3 years and 3 months (1,175 days). Its orbit has an eccentricity of 0.07 and an inclination of 5° with respect to the ecliptic.[1] As no precoveries were taken, and no prior identifications were made, the body's observation arc begins with its official discovery observation.[10]

Physical characteristicsEdit

Rotation periodEdit

Astronomers Laurent Bernasconi and Stéphane Charbonnel obtained a rotational lightcurve of Behrens from photometric observations made in August 2001. It gave a longer than average rotation period of 34.34 hours with a brightness variation of 0.16 magnitude (U=2).[8]

Diameter and albedoEdit

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Behrens measures between 8.96 and 10.33 kilometers in diameter, and its surface has an albedo between 0.20 and 0.318.[4][5][6][7] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the largest member and namesake of this orbital family – and calculates a diameter of 10.31 kilometers with an absolute magnitude of 12.1.[3]


Based on a proposal by Otto Kippes, who verified the discovery, this minor planet was named after Johann Gerhard Behrens (1889–1978), German amateur astronomer and pastor at Detern, in lower Saxony. He was known for his orbit computations on comets and minor planets.[2] The official naming citation was published by the Minor Planet Center on 1 October 1980 (M.P.C. 5523).[11]


  1. ^ a b c d "JPL Small-Body Database Browser: 1651 Behrens (1936 HD)" (2017-05-05 last obs.). Jet Propulsion Laboratory. Retrieved 6 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1651) Behrens". Dictionary of Minor Planet Names – (1651) Behrens. Springer Berlin Heidelberg. p. 131. doi:10.1007/978-3-540-29925-7_1652. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f "LCDB Data for (1651) Behrens". Asteroid Lightcurve Database (LCDB). Retrieved 25 December 2016.
  4. ^ a b c Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 25 December 2016.
  5. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
  6. ^ 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 25 December 2016.
  7. ^ 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 25 December 2016.
  8. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1651) Behrens". Geneva Observatory. Retrieved 25 December 2016.
  9. ^ 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 25 December 2016.
  10. ^ a b "1651 Behrens (1936 HD)". Minor Planet Center. Retrieved 25 December 2016.
  11. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 25 December 2016.

External linksEdit