4486 Mithra
Eccentric asteroid and suspected contact-binary
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4486 Mithra (prov. designation: 1987 SB), is an eccentric asteroid and suspected contact-binary, classified as near-Earth object and potentially hazardous asteroid, approximately 2 kilometers in diameter. It belongs to the Apollo group of asteroids and is a relatively slow rotator.
Radar image of the Asteroid. | |
| Discovery[1] | |
|---|---|
| Discovered by | |
| Discovery site | Rozhen Obs. – Smolyan |
| Discovery date | 22 September 1987 |
| Designations | |
| (4486) Mithra | |
| Pronunciation | /ˈmɪθrə/[2] |
Named after | Mithra (proto-Indo-Iranian religion)[3] |
| |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 29.04 yr (10,607 days) |
| Aphelion | 3.6582 AU |
| Perihelion | 0.7417 AU |
| 2.2000 AU | |
| Eccentricity | 0.6629 |
| 3.26 yr (1,192 days) | |
| 91.928° | |
| 0° 18m 7.2s / day | |
| Inclination | 3.0395° |
| 82.240° | |
| 2023-May-15 | |
| 168.87° | |
| Earth MOID | 0.0463 AU (18 LD) |
| Physical characteristics | |
| S[7] | |
The asteroid was discovered on 22 September 1987, by Belgian astronomer Eric Elst and Bulgarian astronomer Vladimir Shkodrov at Rozhen Observatory, in the Smolyan Province of Bulgaria.[4] It was named after the Indo-Iranian divinity Mithra.[3]
Orbit and classification
Mithra orbits the Sun at a distance of 0.7–3.7 AU once every 3 years and 3 months (1,192 days). Its orbit has an eccentricity of 0.66 and an inclination of 3° with respect to the ecliptic.[1] In 1974, Mithra was first identified as 1974 DN1 at Crimea–Nauchnij. The body's observation arc begins 8 months prior to its official discovery observation, with a precovery taken at the Japanese Kiso Observatory in January 1987.[4]
Close approaches
As a potentially hazardous asteroid, it has a low minimum orbit intersection distance with Earth of 0.0462 AU (6,910,000 km; 18.0 LD).[1] On 14 August 2000, it passed 0.0465 AU (6,960,000 km; 18.1 LD) from Earth.[1]
Physical characteristics
Rotation period and shape
Radar imaging using a delay-Doppler technique at the Arecibo and Goldstone observatories rendered a rotation period of 67.5±6 hours.[8] Based on the radar analysis, Mithra is also a strong candidate for a contact binary, which is composed of two distinct lobes in mutual contact, held together by their weak gravitational attraction. They typically show a bifurcated, dumbbell-like shape (also see 4769 Castalia).[8][13] A large number of near-Earth objects are believed to be contact-binaries.[14]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Mithra measures 1.85 kilometers in diameter and its surface has a high albedo of 0.297, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 2.25 kilometer with an absolute magnitude of 15.6.[5][6][7]
Naming
This minor planet was named after Mithra (also see Mitra), deity in the proto-Indo-Iranian religion. The mystery religion of Mithraism was practiced in the Roman Empire between the 1st and 4th century. Considered to be a rival of early Christianity, both religions shared similar characteristics such as elevation and the ritual of baptism. In the Hellenistic world, Mithra was conflated with Apollo. The asteroid 1862 Apollo is the namesake of this asteroid's orbital group.[3] The approved naming citation was published by the Minor Planet Center on 5 September 1990 (M.P.C. 16885).[15]
