| 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] | |
4486 Mithra (prov. designation:1987 SB), is an eccentricasteroid and suspectedcontact-binary, classified asnear-Earth object andpotentially hazardous asteroid, approximately 2 kilometers in diameter. It belongs to theApollo group of asteroids and is a relativelyslow rotator.
The asteroid was discovered on 22 September 1987, by Belgian astronomerEric Elst and Bulgarian astronomerVladimir Shkodrov atRozhen Observatory, in the Smolyan Province of Bulgaria.[4] It was named after the Indo-Iranian divinityMithra.[3]
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 aneccentricity of 0.66 and aninclination of 3° with respect to theecliptic.[1] In 1974,Mithra was first identified as1974 DN1 atCrimea–Nauchnij. The body'sobservation arc begins 8 months prior to its official discovery observation, with aprecovery taken at the JapaneseKiso Observatory in January 1987.[4]
As a potentially hazardous asteroid, it has a lowminimum 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]
| Date | JPL Horizons nominal geocentric distance (AU) | uncertainty region (3-sigma) |
|---|---|---|
| 2023-Apr-11 16:49 | 0.16267 AU (24.335 million km)[1] | ±47 km[11] |
| Date | JPL Horizons nominal geocentric distance (AU) | uncertainty region (3-sigma) |
|---|---|---|
| 2150-Nov-04 17:06 ± 00:18 | 0.01382 AU (2.067 million km)[1] | ±700 km[12] |
Radar imaging using a delay-Doppler technique at theArecibo andGoldstone observatories rendered arotation period of67.5±6 hours.[8] Based on the radar analysis,Mithra is also a strong candidate for acontact binary, which is composed of two distinct lobes in mutual contact, held together by their weak gravitational attraction. They typically show abifurcated, dumbbell-like shape(also see4769 Castalia).[8][13] A large number of near-Earth objects are believed to be contact-binaries.[14]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Mithra measures 1.85 kilometers in diameter and its surface has a highalbedo of 0.297, while theCollaborative Asteroid Lightcurve Link assumes a standard albedo forstony asteroids of 0.20 and calculates a diameter of 2.25 kilometer with anabsolute magnitude of 15.6.[5][6][7]
Thisminor planet was named afterMithra(also seeMitra), deity in theproto-Indo-Iranian religion. The mystery religion ofMithraism 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 aselevation and the ritual of baptism. In the Hellenistic world, Mithra was conflated withApollo. The asteroid1862 Apollo is the namesake of this asteroid's orbital group.[3] The approved naming citation was published by theMinor Planet Center on 5 September 1990 (M.P.C. 16885).[15]
