| Discovery[1] | |
|---|---|
| Discovered by | M. F. Wolf |
| Discovery site | Heidelberg Obs. |
| Discovery date | 11 February 1921 |
| Designations | |
| (946) Poësia | |
| Pronunciation | /poʊˈiːsiə/[2] |
Named after | poetry (goddess of poetry)[3] |
| A921 CD · 1959 AA A911 KB · 1911 KB 1921 JC | |
| main-belt[1][4] · (outer) Themis[5][6] | |
| Orbital characteristics[4] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 98.66yr (36,034 d) |
| Aphelion | 3.5647AU |
| Perihelion | 2.6709 AU |
| 3.1178 AU | |
| Eccentricity | 0.1433 |
| 5.51 yr (2,011 d) | |
| 30.119° | |
| 0° 10m 44.4s / day | |
| Inclination | 1.4312° |
| 69.661° | |
| 37.936° | |
| Physical characteristics | |
| 108.5±0.5 h[10][11] | |
| 10.6[1][4] | |
946 Poësia/poʊˈiːsiə/ is aThemis asteroid andslow rotator, approximately 39 kilometers (24 miles) in diameter, located in the outer regions of theasteroid belt. It was discovered by German astronomerMax Wolf at theHeidelberg-Königstuhl State Observatory on 11 February 1921 and given theprovisional designationsA921 CD and1921 JC.[1] TheF-type asteroid has a longrotation period of 108.5 hours. It was named after the goddess ofpoetry.[3]
Poësia is a core member of theThemis family (602), a very largefamily of carbonaceous asteroids, named after24 Themis.[5][6][12]: 23 It orbits the Sun in theouter asteroid belt at a distance of 2.7–3.6 AU once every 5 years and 6 months (2,011 days;semi-major axis of 3.12 AU). Its orbit has aneccentricity of 0.14 and aninclination of 1° with respect to theecliptic.[4] The body'sobservation arc begins atHeidelberg Observatory on 11 May 1921, or three months after its official discovery observation.[1]
Thisminor planet was named after the goddess of poetry. The name was proposed by Russian astronomerNikolaj Komendantov (1895–1937), and thenaming was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 91).[3]
In theTholen classification,Poësia is an uncommonF-type asteroid, though with an unusual spectrum,[4] while in the Barucci taxonomy, it is a carbonaceousC0-type.[6] The overallspectral type for members of the Themistian family is that of a C-type.[12]: 23
In January 2009, a rotationallightcurve ofPoësia was obtained fromphotometric observations byRobert Stephens at the Santana Observatory (646) and Goat Mountain Astronomical Research Station (G79) in California. Lightcurve analysis gave an exceptionally longrotation period of108.5±0.5 hours with a brightness amplitude of0.32±0.05magnitude (U=2+).[11] A few weeks later, Gary A. Vander Haagen at Stonegate Observatory (H67) determined an ambiguous period of 73.5 or 102.9 hours with an amplitude of0.24±0.05 magnitude (U=2),[13] whileRené Roy measured a tentative period of 48 hours (U=1).[14] With a best-rated period of 108.5 hours,Poësia is aslow rotator. While theslowest rotators have periods above 1000 hours, the vast majority of asteroids have periods between 2.2 and 20 hours.
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE), and the Infrared Astronomical SatelliteIRAS,Poësia measures36.210±0.149,39.60±0.64 and43.75±4.6 kilometers in diameter, and its surface has a correspondingalbedo of0.097±0.008,0.079±0.003 and0.0627±0.015, respectively.[7][8][9] TheCollaborative Asteroid Lightcurve Link adopts the results from IRAS, that is, an albedo of 0.0627 and a diameter of 43.75 km based on anabsolute magnitude of 9.8.[10]
Further published mean-diameters and albedos by the WISE team include33.30±10.10 km,35.84±11.06 km,37.604±0.255 km and38.990±0.248 km with albedos of0.06±0.06,0.06±0.04,0.097±0.008 and0.0789±0.0085, respectively.[6][10]
