1669 Dagmar

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1669 Dagmar
Discovery [1]
Discovered by K. Reinmuth
Discovery site Heidelberg Obs.
Discovery date 7 September 1934
MPC designation (1669) Dagmar
Named after
Generic name
(common German name)[2]
1934 RS · 1943 GE
1950 PX · 1953 AD
1957 WA · 1959 CV
1962 RH
main-belt · Themis[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 82.66 yr (30,190 days)
Aphelion 3.4870 AU
Perihelion 2.7920 AU
3.1395 AU
Eccentricity 0.1107
5.56 yr (2,032 days)
0° 10m 37.92s / day
Inclination 0.9409°
Physical characteristics
Dimensions 35.78±2.4 km (IRAS:17)[4]
42.377±0.188 km[5]
42.99±2.86 km[6]
43.00±0.77 km[7]
45.194±0.620 km[8]
Mass (3.98±0.80)×1016 kg[6]
Mean density
0.95±0.27 g/cm3[6]
12 h[9]
0.0565±0.008 (IRAS:17)[4]
Tholen = G:[1] · G:[3]
B–V = 0.730[1]
U–B = 0.460[1]
10.91±0.18[10] · 10.97 (IRAS:17)[1][3][4] · 10.97[7][8]

1669 Dagmar, provisional designation 1934 RS, is a rare-type Themistian asteroid from the outer region of the asteroid belt, approximately 42 kilometers in diameter. It was discovered on 7 September 1934, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany, and named after a common German feminine name.[2][11]

Classification and orbit[edit]

The asteroid is a member of the Themis family, a large group of asteroids in the outer main-belt. It orbits the Sun at a distance of 2.8–3.5 AU once every 5 years and 7 months (2,032 days). Its orbit has an eccentricity of 0.11 and an inclination of 1° with respect to the ecliptic.[1] As no precoveries were taken, and no prior identifications were made, Dagmar's observation arc begins with its official discovery observation.[11]

Physical characteristics[edit]

Dagmar has a rare spectra of a G-type asteroid (or Cg-type in the SMASS taxonomy), similar to 1 Ceres, the largest asteroid and only dwarf planet in the asteroid belt.[1]

Rotation period[edit]

Astronomer Federico Manzini obtained a provisional lightcurve of Dagmar from photometric observations in March 2004. It gave a tentative rotation period of 12 hours with a brightness variation of 0.15 magnitude (U=1).[9] As of 2017, no secure period has yet been published.[1]

Diameter and albedo[edit]

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, Dagmar measures between 35.78 and 45.194 kilometers in diameter, and its surface has an albedo between 0.035 and 0.057.[4][5][7][8] The Collaborative Asteroid Lightcurve Link adopts the results obtained by 17 observations made by IRAS, that is an albedo of 0.0565 and a diameter of 35.78 kilometers with an absolute magnitude of 10.97.[3]


This minor planet was named by the discoverer after a common German feminine name. No special meaning is assigned to this name.[2] The official naming citation was published by the Minor Planet Center before November 1977 (M.P.C. 2901).[12]


  1. ^ a b c d e f g h i "JPL Small-Body Database Browser: 1669 Dagmar (1934 RS)" (2017-05-04 last obs.). Jet Propulsion Laboratory. Retrieved 6 June 2017. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1669) Dagmar. Springer Berlin Heidelberg. p. 133. ISBN 978-3-540-00238-3. Retrieved 23 December 2016. 
  3. ^ a b c d "LCDB Data for (1669) Dagmar". Asteroid Lightcurve Database (LCDB). Retrieved 23 December 2016. 
  4. ^ 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. Bibcode:2004PDSS...12.....T. Retrieved 23 December 2016. 
  5. ^ 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:1406.6645Freely accessible. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 23 December 2016. 
  6. ^ a b c Carry, B. (December 2012). "Density of asteroids". Planetary and Space Science. 73 (1): 98–118. arXiv:1203.4336Freely accessible. Bibcode:2012P&SS...73...98C. doi:10.1016/j.pss.2012.03.009. Retrieved 23 December 2016. 
  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 23 December 2016. 
  8. ^ 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" (PDF). The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 23 December 2016. 
  9. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1669) Dagmar". Geneva Observatory. Retrieved 23 December 2016. 
  10. ^ 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:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 23 December 2016. 
  11. ^ a b "1669 Dagmar (1934 RS)". Minor Planet Center. Retrieved 23 December 2016. 
  12. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 23 December 2016. 

External links[edit]