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1695 Walbeck, provisional designation 1941 UO, is a carbonaceous asteroid from the central region of the asteroid belt, approximately 19 kilometers in diameter. It was discovered on 15 October 1941, by Finnish astronomer Liisi Oterma at Turku Observatory in Southwest Finland, and named after Henrik Walbeck.[2][12]

1695 Walbeck
Discovery [1]
Discovered byL. Oterma
Discovery siteTurku Obs.
Discovery date15 October 1941
MPC designation(1695) Walbeck
Named after
Henrik Walbeck (geodesist)[2]
1941 UO · 1964 QA
1964 RE
main-belt · (middle)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc75.44 yr (27,554 days)
Aphelion3.5921 AU
Perihelion1.9703 AU
2.7812 AU
4.64 yr (1,694 days)
0° 12m 45s / day
Physical characteristics
Dimensions17.88±0.27 km[4]
18.953±0.258 km[5][6]
19.60 km (derived)[3]
19.62±0.8 km[7]
19.84±0.29 km[8]
5.16±0.05 h[9]
5.1607±0.0006 h[9]
5.3 h[10]
0.0460 (derived)[3]
SMASS = Cg [1] · C[3]
12.4[5][7][8] · 12.5[1][3] · 12.76±0.23[11] · 12.93[4]


Classification and orbitEdit

The asteroid orbits the Sun in the central main-belt at a distance of 2.0–3.6 AU once every 4 years and 8 months (1,694 days). Its orbit has an eccentricity of 0.29 and an inclination of 17° with respect to the ecliptic.[1] Walbeck's observation arc begins the night after its official discovery observation.[12]

Physical characteristicsEdit

In the SMASS taxonomy, the carbonaceous asteroid is characterized as a Cg-type, an intermediate between the C-type and G-type asteroids.[1]


In November 2006, a rotational lightcurve of Walbeck was obtained from photometric observations by French amateur astronomer Pierre Antonini. It gave a rotation period of 5.1607 hours with a brightness variation of 0.22 magnitude (U=3).[9] Two similar periods were obtained by David Romeuf and by a team of Hungarian astronomers (U=2/2).[9][10]

Diameter and albedoEdit

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Walbeck measures between 17.88 and 19.62 kilometers in diameter and its surface has an albedo between 0.037 and 0.051.[4][5][7][8] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.046 and a diameter of 19.60 kilometers based on an absolute magnitude of 12.5.[3]


The minor planet was named in memory of Finnish scientist Henrik Johan Walbeck (1793–1822), astronomer and geodesist at the old Academia Aboensis who used the method of least squares to derive a good value for the Earth's flattening.[2] The official naming citation was published by the Minor Planet Center on 1 April 1980 (M.P.C. 5281).[13]


  1. ^ a b c d e f "JPL Small-Body Database Browser: 1695 Walbeck (1941 UO)" (2017-03-24 last obs.). Jet Propulsion Laboratory. Retrieved 6 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1695) Walbeck". Dictionary of Minor Planet Names – (1695) Walbeck. Springer Berlin Heidelberg. p. 135. doi:10.1007/978-3-540-29925-7_1696. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f "LCDB Data for (1695) Walbeck". Asteroid Lightcurve Database (LCDB). Retrieved 17 December 2016.
  4. ^ 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 17 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 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 17 December 2016.
  7. ^ a b c d Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 17 December 2016.
  8. ^ 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 17 December 2016.
  9. ^ a b c d Behrend, Raoul. "Asteroids and comets rotation curves – (1695) Walbeck". Geneva Observatory. Retrieved 17 December 2016.
  10. ^ a b Székely, P.; Kiss, L. L.; Szabó, Gy. M.; Sárneczky, K.; Csák, B.; Váradi, M.; et al. (August 2005). "CCD photometry of 23 minor planets". Planetary and Space Science. 53 (9): 925–936. arXiv:astro-ph/0504462. Bibcode:2005P&SS...53..925S. doi:10.1016/j.pss.2005.04.006. Retrieved 17 December 2016.
  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. Retrieved 17 December 2016.
  12. ^ a b "1695 Walbeck (1941 UO)". Minor Planet Center. Retrieved 17 December 2016.
  13. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 17 December 2016.

External linksEdit