| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin E. Shoemaker |
| Discovery site | Palomar Obs. |
| Discovery date | 11 October 1982 |
| Designations | |
| (4197) Morpheus | |
| Pronunciation | /ˈmɔːrfiːəs/[2] |
Named after | Morpheus (mythology andmovie)[3] |
| 1982 TA | |
| Apollo · NEO Mars-crosser Venus-crosser | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 61.98 yr (22,639 days) |
| Earliestprecovery date | 3 September 1954 |
| Aphelion | 4.0690AU |
| Perihelion | 0.5246 AU |
| 2.2968 AU | |
| Eccentricity | 0.7716 |
| 3.48yr (1,271 days) | |
| 339.88° | |
| 0° 16m 59.16s / day | |
| Inclination | 12.577° |
| 7.1844° | |
| 122.40° | |
| Earth MOID | 0.0987 AU · 38.5LD |
| Physical characteristics | |
| 1.8 km(dated)[1] 2.20 km(dated)[4] 2.98 km(taken)[5] 2.981 km[6] 3.043±0.156 km[7] | |
| 3.5372h[8] 3.5380 h[9] 3.5387 h[10] 3.540±0.001 h[11] 3.560 h[12] | |
| 0.2389[5][6] 0.276±0.077[7] 0.44[4] | |
| SMASS = Sq[1] · S[5] | |
| 14.6[1][7] · 14.8[4][5][6][11] · 14.88[9] | |
4197 Morpheus, provisional designation1982 TA, is a highly eccentricasteroid andnear-Earth object of theApollo group, approximately 3 kilometers in diameter. It was discovered on 11 October 1982, by American astronomersEleanor Helin andEugene Shoemaker atPalomar Observatory in California, United States. The asteroid was later named forMorpheus from Greek mythology.[3]
Morpheus orbits the Sun at a distance of 0.5–4.1 AU once every 3 years and 6 months (1,271 days). Its orbit has aneccentricity of 0.77 and aninclination of 13° with respect to theecliptic.[1] Due to this elongated orbit, the asteroid is both, aMars-crosser and aVenus-crosser.
It has aminimum orbit intersection distance with Earth of 0.0987 AU (14,800,000 km), which corresponds to 38.5lunar distances.[1]
A firstprecovery was taken at the discovering observatory in 1954, extending the body'sobservation arc by 28 years prior to its official discovery observation.[3]
On theSMASS taxonomic scheme,Morpheus is classified as a stony Sq sub-type, which transitions from the commonS-type to the rather rareQ-type asteroids.[1]
In the 1990s,Tom Gehrels gave a first diameter estimate forMorpheus of 1.8 kilometers.[1]According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE), it measures 3.043 kilometers in diameter and its surface has analbedo of 0.276.[7] In 2012, a revision of the published WISE-data byPetr Pravec gave a diameter of 2.981 kilometers and an albedo of 0.2389.[6] TheCollaborative Asteroid Lightcurve Link adopts the revised WISE-data and takes a diameter of 2.98 kilometers with anabsolute magnitude of 14.8.[5]
In 1996, a rotationallightcurve was obtained by Czech astronomerPetr Pravec at theOndřejov Observatory during the body's close approach to Earth within 0.1 AU. It gave a well-definedrotation period of3.5380 hours with a brightness variation of 0.49magnitude (U=3).[9]
At the same time, astronomers at theGoldstone Observatory analysedMorpheus usingradar delay-Doppler imaging. The resultant images are not very clear, but they show that the body has a roughly triangular shape, and a 3-hour rotation period.[citation needed]
Seven years later, during the asteroid's next close approach in 2003,Morpheus was observed for five nights by Slovak astronomerAdrián Galád at theModra Observatory. Lightcurve analysis showed a concurring period of3.5387 hours and an amplitude of 0.4 in magnitude (U=3).[10]
Thisminor planet was named afterMorpheus fromGreek mythology. He is a god of dreams who appears in the poemMetamorphoses written by the Roman poetOvid. He is capable to imitate any human form and to appear in dreams.
The approved naming citation was published by theMinor Planet Center on 5 January 2015 (M.P.C. 91790).[13]
