| Discovery[1] | |
|---|---|
| Discovered by | C. Shoemaker |
| Discovery site | Palomar Obs. |
| Discovery date | 4 May 1986 |
| Designations | |
| (4340) Dence | |
Named after | Michael R. Dence[1] (Canadian geologist) |
| 1986 JZ · 1982 KF4 1986 LN | |
| main-belt[1][2] · (inner) background[3] · Phocaea[4] | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 38.28yr (13,983 d) |
| Aphelion | 2.9475AU |
| Perihelion | 1.8408 AU |
| 2.3941 AU | |
| Eccentricity | 0.2311 |
| 3.70 yr (1,353 d) | |
| 212.55° | |
| 0° 15m 57.96s / day | |
| Inclination | 25.155° |
| 81.012° | |
| 175.79° | |
| Physical characteristics | |
| 8.110±0.138 km[5][6] 8.37 km(calculated)[4] | |
| 7.546±0.005 h[7] 7.558±0.0018 h[a] 7.5668±0.0018 h[a] 15.473±0.005 h(poor)[8] | |
| 0.155±0.028[5][6] 0.23(assumed)[4] | |
| SMASS =S[2][4] | |
| 12.6[2][4] 12.67±1.14[9] 13.1[6] | |
4340 Dence, provisional designation1986 JZ, is a background or Phocaeaasteroid from the inner regions of theasteroid belt, approximately 8 kilometers (5 miles) in diameter. It was discovered on 4 May 1986, by American astronomerCarolyn Shoemaker at thePalomar Observatory in California.[1] TheS-type asteroid has arotation period of 7.5 hours.[4] It was named after Canadian geologistMichael R. Dence.[1]
Dence is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[3] Based on osculating Keplerianorbital elements, the asteroid has also been classified as a member of the stonyPhocaea family (701).[4] It orbits the Sun in theinner asteroid belt at a distance of 1.8–2.9 AU once every 3 years and 8 months (1,353 days;semi-major axis of 2.39 AU). Its orbit has aneccentricity of 0.23 and aninclination of 25° with respect to theecliptic.[2] The body'sobservation arc begins with aprecovery taken at theSiding Spring Observatory in November 1979, more than six years prior to its official discovery observation at Palomar.[1]
In theSMASS classification,Dence is a common, stonyS-type asteroid.[2][4]
Since 2008, several rotationallightcurves ofDence have been obtained fromphotometric observations by Czech astronomerPetr Pravec and by Maurice Clark at the observatory of theMontgomery College in Maryland, United States (U=3-/1/2/2).[7][8][a] Analysis of the best-rated lightcurve gave arotation period of 7.546 hours with a brightness amplitude of 0.58magnitude (U=3-).[4][7]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Dence measures 8.110 kilometers in diameter and its surface has analbedo of 0.155,[5][6] while theCollaborative Asteroid Lightcurve Link assumes an albedo of 0.23 – derived from25 Phocaea, theparent body of the Phocaea family – and calculates a diameter of 8.37 kilometers based on anabsolute magnitude of 12.6.[4]
Thisminor planet was named after Canadian geologistMichael R. Dence executive director of theRoyal Society of Canada. He was a pioneer in the geologic investigation of ancientimpact craters on theCanadian Shield(also seeSudbury Basin andManicouagan Reservoir).[1] The official naming citation was published by theMinor Planet Center on 30 January 1991 (M.P.C. 17656).[10]
