 Orbit of 4001 Ptolemaeus | |
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 2 August 1949 |
| Designations | |
| (4001) Ptolemaeus | |
| Pronunciation | /tɒləˈmiːəs/ |
Named after | Ptolemy[1] (Greco-Roman astronomer) |
| 1949 PV · 1949 QD1 1982 BU9 · 1987 OE | |
| main-belt[1][2] · (inner) Flora[3] | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 67.75yr (24,744 d) |
| Aphelion | 2.6809AU |
| Perihelion | 1.8940 AU |
| 2.2874 AU | |
| Eccentricity | 0.1720 |
| 3.46 yr (1,264 d) | |
| 294.51° | |
| 0° 17m 5.64s / day | |
| Inclination | 5.4568° |
| 130.67° | |
| 204.09° | |
| Physical characteristics | |
| 4.641±0.297 km[4] 5.0 km(est. at0.24)[5] | |
| 0.392±0.056[4] | |
| SMASS =S[2] | |
| 13.7[2] | |
4001 Ptolemaeus, provisional designation1949 PV, is a Florianasteroid from the inner regions of theasteroid belt, approximately 5 kilometers (3.1 miles) in diameter. It was discovered on 2 August 1949, by German astronomerKarl Reinmuth at theHeidelberg-Königstuhl State Observatory in Heidelberg, Germany. In 1991, theInternational Astronomical Union named theS-type asteroid after Greco-Roman astronomerPtolemy.[1]
Ptolemaeus is a member of theFlora family (402),[3] a giantasteroid family and the largest family of stony asteroids in the main-belt.[6] It orbits the Sun in theinner main-belt at a distance of 1.9–2.7 AU once every 3 years and 6 months (1,264 days;semi-major axis of 2.29 AU). Its orbit has aneccentricity of 0.17 and aninclination of 5° with respect to theecliptic.[2]
The body'sobservation arc begins with its observations as1949 QD1 atLowell Observatory on 24 August 1949, or three weeks after its official discovery observation at Heidelberg.[1] On 24 April 1989,Ptolemaeus approached the asteroid6 Hebe within 5.5 million kilometers at a relative velocity of 3.7 km/s.[2]
In theSMASS classification,Ptolemaeus is a common, stonyS-type asteroid, which is in agreement with the overallspectral type for members of the Flora family.[6]: 23
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Ptolemaeus measures 4.641 kilometers in diameter and its surface has a highalbedo of 0.392.[4] Based on a generic magnitude-to-diameter conversion, assuming a Flora-type typical albedo of 0.24, the asteroid measures 5.0 kilometers for anabsolute magnitude of 13.7.[5]
As of 2018, no rotationallightcurve ofPtolemaeus has been obtained fromphotometric observations. Itsrotation period,poles and shape remain unknown.[2]
Thisminor planet was named after 2nd-century Greco-Roman astronomerPtolemy (Latin: "Ptolemaeus") byIAU'sMinor Planet Names Committee. He is best known for his influentialAlmagest, a mathematical and astronomical treatise on the apparent motions of the stars and planetary paths. Its ideas dominated astronomy for 1200 years untilCopernicus in the early Renaissance.[1] The official naming citation was published by theMinor Planet Center on 21 November 1991 (M.P.C. 19335).[7]
