| Discovery[1] | |
|---|---|
| Discovered by | C. J. van Houten I. van Houten-G. T. Gehrels |
| Discovery site | Palomar Obs. |
| Discovery date | 17 October 1960 |
| Designations | |
| (6615) Plutarchos | |
| Pronunciation | /pluːˈtɑːrkəs/[2] |
Named after | Plutarch (Greek philosopher)[3] |
| 9512 P-L · 1991 EW | |
| main-belt · Flora[4] | |
| Adjectives | Plutarchian/pluːˈtɑːrkiən/[5] |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 55.42 yr (20,242 days) |
| Aphelion | 2.4440AU |
| Perihelion | 1.8951 AU |
| 2.1695 AU | |
| Eccentricity | 0.1265 |
| 3.20yr (1,167 days) | |
| 73.475° | |
| 0° 18m 30.24s / day | |
| Inclination | 1.7970° |
| 129.37° | |
| 81.057° | |
| Knownsatellites | 1(period 40.02 h)[6] |
| Physical characteristics | |
| Dimensions | 3.11 km(calculated)[4] 3.139±0.045 km[7][8] |
| 2.3247±0.0001h[6] | |
| 0.24(assumed)[4] 0.412±0.066[7][8] | |
| S[4] | |
| 14.0[7] · 14.7[1][4] · 14.71±0.22[9] | |
6615 Plutarchos, provisional designation9512 P-L, is a Florianasteroid and suspectedbinary from the inner regions of theasteroid belt, approximately 3.1 kilometers in diameter. Discovered during thePalomar–Leiden survey in 1960, the asteroid was later named after the Greek philosopherPlutarch.[3] Itsminor-planet moon was discovered in 2007.
Plutarchos was discovered on 17 October 1960, by Dutch astronomer coupleIngrid andCornelis van Houten at Leiden, on photographic plates exposed by Dutch–American astronomerTom Gehrels atPalomar Observatory in California, United States.[10]
Thesurvey designation "P-L" stands forPalomar–Leiden, named after Palomar Observatory andLeiden Observatory, which collaborated on the fruitfulPalomar–Leiden survey in the 1960s. Gehrels used Palomar'sSamuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped thephotographic plates to Ingrid and Cornelis van Houten at Leiden Observatory whereastrometry was carried out. The trio are credited with the discovery of several thousand minor planets.[11]
TheS-type asteroid is a member of theFlora family, one of the largest groups of stony asteroids in the main-belt. It orbit has aneccentricity of 0.13 and aninclination of 2° with respect to theecliptic.[1] As noprecovery were taken, and no prior identifications were made, the body'sobservation arc begins with its official discovery observation at Palomar in 1960.[10]
A rotationallightcurve ofPlutarchos was obtained from photometric observations taken by astronomers Julian Oey,Donald Pray andPetr Pravec in April 2007. Lightcurve analysis gave a well-definedrotation period of 2.3247 hours with a brightness variation of 0.06 inmagnitude, indicating a nearly spheroidal shape (U=3).[6] For an asteroid of its size,Plutarchos rotates rapidly, close to the 2.2-hour threshold spin rate forfast rotators.
During the photometric observations in 2007, mutual eclipse/occultation events suggested thatPlutarchos is a synchronousbinary asteroid with aminor-planet moon orbiting it every 40.02 hours. However, neither a diameter estimate for the suspected satellite, nor any follow-up observations have been published since 2007.[4][6]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Plutarchos measures 3.139 kilometers in diameter, and its surface has a very highalbedo of 0.412,[7][8] while theCollaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from8 Flora, the family's largest member and namesake – and calculates a diameter of 3.11 kilometers, based on anabsolute magnitude of 14.7.[4]
Thisminor planet was named for the Greek writer and Platonic philosopherPlutarch (c. AD 45–125), known for hisParallel Lives andMoralia a collection of biographies and essays, respectively. Plutarch studied mathematics and philosophy at the Academy of Athens. It is estimated that about half of his philosophical work has survived.[3] The approved naming citation was published by theMinor Planet Center on 4 April 1996 (M.P.C. 26932).[12]
