| Discovery[1] | |
|---|---|
| Discovered by | M. F. Wolf |
| Discovery site | Heidelberg Obs. |
| Discovery date | 5 October 1931 |
| Designations | |
| (1203) Nanna | |
Named after | Anna Risi (model of painter) Anselm Feuerbach[2] |
| 1931 TA · 1926 RH 1978 AD | |
| main-belt · (outer)[3] | |
| Orbital characteristics[1] | |
| Epoch 16 February 2017 (JD 2457800.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 90.24 yr (32,960 days) |
| Aphelion | 3.6055AU |
| Perihelion | 2.1795 AU |
| 2.8925 AU | |
| Eccentricity | 0.2465 |
| 4.92yr (1,797 days) | |
| 137.21° | |
| 0° 12m 1.44s / day | |
| Inclination | 5.9706° |
| 224.58° | |
| 176.38° | |
| Physical characteristics | |
| Dimensions | 31.80±1.22 km[4] 32.59±0.87 km[5] 35.06 km(derived)[3] 35.18±3.9 km(IRAS:2)[6] 35.92±15.13 km[7] 37.91±12.03 km[8] |
| 15.6±0.1h(dated)[9] 18.54±0.01 h[10] 25.80±0.05 h[11] | |
| 0.028±0.017[7] 0.03±0.01[8] 0.03(derived)[3] 0.04±0.00[4] 0.0473±0.012(IRAS:2)[6] 0.056±0.004[5] | |
| C[3] | |
| 11.20[5][6] · 11.60[8] · 11.63±0.24[12] · 11.7[1][3] · 11.71[4][7] | |
1203 Nanna (provisional designation1931 TA) is a carbonaceousasteroid from the outer region of theasteroid belt, about 35 kilometers in diameter. It was discovered on 5 October 1931, by German astronomerMax Wolf atHeidelberg Observatory in southwest Germany,[13] and named afterAnna Risi, a model and mistress of painterAnselm Feuerbach.[2]
Nanna is a darkC-type asteroid. It orbits the Sun at a distance of 2.2–3.6 AU once every 4 years and 11 months (1,797 days). Its orbit has aneccentricity of 0.25 and aninclination of 6° with respect to theecliptic.[1] In 1926, it was first identified as1926 RH, extending the body'sobservation arc by 5 years prior to its official discovery observation.[13]
In September 2009, two rotationallightcurves of Nanna were obtained by American astronomerBrian Warner from photometric observations at his Palmer Divided Observatory in Colorado. The first lightcurve analysis gave arotation period of 18.54 hours with a brightness variation of 0.12magnitude (U=2), while the second lightcurve was ambiguous giving a period of 25.80 and 12.90 hours, respectively, and an amplitude of 0.15 (U=2).[10] These results supersede a fragmentary lightcurve taken by French amateur astronomers Federico Manzini,Laurent Bernasconi andRené Roy from August 2004, which gave a period of 15.6 hours (U=1).[9]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite, and NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission, Nanna measures between 31.80 and 37.91 kilometers in diameter and its surface has analbedo of 0.028 and 0.056.[4][5][6][7][8] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.03 and a diameter of 35.06 kilometers with anabsolute magnitude of 11.7.[3]
Thisminor planet was named afterAnna Risi, a model in several paintings by German classicist painterAnselm Feuerbach.[2] The official naming citation was published byPaul Herget inThe Names of the Minor Planets in 1955 (H 112).[2]
