1669 Dagmar

1669 Dagmar
Discovery
Discovered by	K. Reinmuth
Discovery site	Heidelberg Obs.
Discovery date	7 September 1934
Designations
MPC designation	(1669) Dagmar
Named after	Generic name; (common German name)
Alternative designations	1934 RS · 1943 GE; 1950 PX · 1953 AD; 1957 WA · 1959 CV; 1962 RH
Minor planet category	main-belt · Themis
Orbital characteristics
	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
Semi-major axis	3.1395 AU
Eccentricity	0.1107
Orbital period (sidereal)	5.56 yr (2,032 days)
Mean anomaly	126.58°
Mean motion	0° 10m 37.92s / day
Inclination	0.9409°
Longitude of ascending node	18.979°
Argument of perihelion	178.21°
Physical characteristics
Dimensions	35.78±2.4 km (IRAS:17); 42.377±0.188 km; 42.99±2.86 km; 43.00±0.77 km; 45.194±0.620 km
Mass	(3.98±0.80)×1016 kg
Mean density	0.95±0.27 g/cm3
Synodic rotation period	12 h
Geometric albedo	0.0354±0.0061; 0.039±0.007; 0.0565±0.008 (IRAS:17)
Spectral type	Tholen = G: · G:; B–V = 0.730; U–B = 0.460
Absolute magnitude (H)	10.91±0.18 · 10.97 (IRAS:17) · 10.97

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

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

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

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

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]

Naming

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]

References

^ ^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.
^ ^a ^b ^c Schmadel, Lutz D. (2007). "(1669) Dagmar". Dictionary of Minor Planet Names – (1669) Dagmar. Springer Berlin Heidelberg. p. 133. doi:10.1007/978-3-540-29925-7_1670. ISBN 978-3-540-00238-3.
^ ^a ^b ^c ^d "LCDB Data for (1669) Dagmar". Asteroid Lightcurve Database (LCDB). Retrieved 23 December 2016.
^ ^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 – IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 17 October 2019.
^ ^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 23 December 2016.
^ ^a ^b ^c Carry, B. (December 2012). "Density of asteroids". Planetary and Space Science. 73 (1): 98–118. arXiv:1203.4336. Bibcode:2012P&SS...73...98C. doi:10.1016/j.pss.2012.03.009. Retrieved 23 December 2016.
^ ^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. (online, AcuA catalog p. 153)
^ ^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.
^ ^a ^b Behrend, Raoul. "Asteroids and comets rotation curves – (1669) Dagmar". Geneva Observatory. Retrieved 23 December 2016.
^ 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 23 December 2016.
^ ^a ^b "1669 Dagmar (1934 RS)". Minor Planet Center. Retrieved 23 December 2016.
^ Schmadel, Lutz D. "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.