| Discovery [1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 7 September 1934 |
| Designations | |
| (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) | |
| 126.58° | |
| 0° 10m 37.92s / day | |
| Inclination | 0.9409° |
| 18.979° | |
| 178.21° | |
| 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] | |
| 0.0354±0.0061 [8] 0.039±0.007 [5] [7] 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]
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]
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]
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]
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 on 15 December 1968 ( M.P.C. 2901). [12]