Discovery | |
---|---|
Discovered by | John Russell Hind |
Discovery date | 24 June 1852 |
Designations | |
(18) Melpomene | |
Pronunciation | /mɛlˈpɒmɪniː/ [1] |
Named after | Melpomenē |
Main belt | |
Adjectives | Melpomenean /mɛlpɒmɪˈniːən/ [2] |
Symbol | (historical) |
Orbital characteristics [3] | |
Epoch 13 September 2023 ( JD 2453300.5) | |
Aphelion | 2.797 AU (418.4 million km) |
Perihelion | 1.794 AU (268.4 million km) |
2.296 AU (343.5 million km) | |
Eccentricity | 0.21839 |
1,270.62 d (3.48 yr) | |
0.3995° | |
Inclination | 10.132° |
150.36° | |
2023-Sep-11 | |
228.15° | |
Earth MOID | 0.81 AU (121 million km) |
Physical characteristics | |
Dimensions | 170 × 155 × 129 km
[4] (150 × 125 km) [5] (150 × 170 km) [6] |
141±2 km
[7] 139.594±2.452 km [3] | |
Flattening | 0.19 [a] |
Mass | (4.5±0.9)×1018 kg
[7] 3.0×1018 kg [4] |
Mean
density | 3.06±0.62 g/cm3
[7] 1.69±0.66 g/cm3 [4] |
0.48221 d (11.57 h) [3] [8] | |
0.221 (calculated)
[7] 0.223 [9] 0.181 ± 0.033 [3] | |
S [3] | |
7.5 [10] to 12.0 | |
6.35 [3] | |
0.23" to 0.059" | |
Melpomene ( minor planet designation: 18 Melpomene) is a large, bright main-belt asteroid that was discovered by J. R. Hind on 24 June 1852, [11] and named after Melpomenē, the Muse of tragedy in Greek mythology. Its historical symbol was a dagger over a star; it is in the pipeline for Unicode 17.0 as U+1CECB ( ). [12] [13]
Melpomene is classified as an S-type asteroid and is composed of silicates and metals. This asteroid is orbiting the Sun at a distance of 2.296 AU with a period of 3.48 years and an eccentricity (ovalness) of 0.22. The orbital plane is tilted at an angle of 10.1° to the plane of the ecliptic. [3]
Melpomene occulted the star SAO 114159 on 11 December 1978. A possible Melpomenean satellite with a diameter at least 37 km was detected. The satellite candidate received a provisional designation S/1978 (18) 1. [14] In 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty. [15] Melpomene was observed with the Hubble Space Telescope in 1993. It was able to resolve the asteroid's slightly elongated shape, but no satellites were detected. [5]
Melpomene has been studied by radar. [16] Photometric observations during 2012 provided a rotation period of 11.571±0.001 h with a brightness variation of 0.34±0.02 in magnitude, which is consistent with previous studies. [17] It has a mean diameter of 141±2 km. [7] [3]
Melpomene can reach an apparent magnitude of +7.9 at a favorable opposition near perihelion, such as occurred in September 2002 when it was 0.814 AU (121.8 million km; 317 LD) from Earth. [18]