| Discovery[1] | |
|---|---|
| Discovered by | N. Chernykh |
| Discovery site | Crimean Astrophysical Obs. |
| Discovery date | 16 May 1966 |
| Designations | |
| (1796) Riga | |
Named after | Riga(capital city)[2] |
| 1966 KB · 1935 GE 1941 FC1 · 1947 GA 1950 TF2 · 1953 GW 1960 JA · A907 TG A907 UD | |
| main-belt · (outer)[1] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 66.06 yr (24,129 days) |
| Aphelion | 3.5474AU |
| Perihelion | 3.1668 AU |
| 3.3571 AU | |
| Eccentricity | 0.0567 |
| 6.15yr (2,247 days) | |
| 142.11° | |
| 0° 9m 36.72s / day | |
| Inclination | 22.585° |
| 186.73° | |
| 9 August 2027[3] | |
| 25.620° | |
| Physical characteristics | |
| Dimensions | 66.2±6.6 km[4] 68.089±1.037 km[5] 68.167±0.298 km[6] 71±7 km[7] 73.83±1.8 km[8] 85.79±1.57 km[9] |
| 10.608±0.002h[10][a] 11.0±0.01 h[11] 16 h[12] 22.226±0.001 h[13] | |
| 0.028±0.001[9] 0.0376±0.002[8] 0.04±0.01[7] 0.044±0.005[6] 0.0442±0.0082[5] 0.05±0.01[4] | |
| XFCU(Tholen)[1] Cb(SMASS)[1] P[5] · C[14][15] B–V = 0.676[1] U–B = 0.289[1] | |
| 14.3[16] to 16.4 | |
| 9.59±0.40[15] · 9.84(IRAS:12)[1][8] · 9.84[4][5][7][9][14] | |
1796 Riga, provisional designation1966 KB, is a darkasteroid from the outer region of theasteroid belt, approximately 70 kilometers in diameter. It was discovered on 16 May 1966, by Russian astronomerNikolai Chernykh at theCrimean Astrophysical Observatory in Nauchnyj, on the Crimean peninsula.[17] It is named after the Latvian capitalRiga.[2] It came toopposition on 21 January 2026 atapparent magnitude 15.1 in the constellation ofMonoceros.[18]
The asteroid orbits the Sun in theouter main-belt at a distance of 3.2–3.5 AU once every 6 years and 2 months (2,247 days). Its orbit has aneccentricity of 0.06 and aninclination of 23° with respect to theecliptic.[1] The body was first identified as "1907 TG" at the U.S Taunton Observatory (803) in 1907, and its first usedprecovery was taken at theGoethe Link Observatory in 1953, extending the asteroid'sobservation arc by 13 years prior to its official discovery observation.[17] It is a member of theCybele group of asteroids.[19]
The carbonaceousC-type asteroid is also classified as a very dark and featureless reddishP-type body by theNEOWISE survey of theWide-field Infrared Survey Explorer (WISE).[5][14][15] In theTholen andSMASS taxonomy, it has a XFCU and Cb subtype, respectively.[1]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite and NASA's WISE/NEOWISE mission, the asteroid measures between 66.2 and 85.7 kilometers in diameter and its surface has analbedo between 0.028 and 0.05.[4][5][6][7][8][9] TheCollaborative Asteroid Lightcurve Link (CALL) agrees with the results obtained by IRAS, adopting a diameter of 73.83 kilometers with an albedo of 0.0376, based on an absolutemagnitude of 9.84.[14]
Several rotationallightcurve for this asteroid were obtained from photometric observations since 1997. They gave a variety ofrotation periods from 10.608 to 22.226 hours with inconsistent brightness variations in the range of 0.05 to 0.40 magnitude (U=2/2-/n.a./2).[10][11][12][13][a] CALL adopts the results of the most observations made by astronomer Julian Oey at the Australian Blue Mountains Observatory(Q68) in March 2014, which gave a period of22.226±0.001 hours and an amplitude of0.40±0.05 magnitude (U=2).[13][14]
The minor planet was named afterRiga, the capital of Latvia and location of the Astronomical Observatory of theUniversity of Latvia. The name was proposed by Matiss A. Dirikis, who was a member of the observatory at the Latvian State University, and after whom the asteroid1805 Dirikis is named.[2] The officialnaming citation was published by theMinor Planet Center on 25 September 1971 (M.P.C. 3185).[20]
