4486 Mithra

4486 Mithra

Discovery
Discovered by	E. W. Elst V. G. Shkodrov
Discovery site	Rozhen Obs. – Smolyan
Discovery date	22 September 1987
Designations
MPC designation	4486 Mithra
Named after	Mithra (proto-Indo-Iranian religion)
Alternative names	1987 SB · 1974 DN1
Minor planet category	Apollo · NEO · PHA
Orbital characteristics
Epoch 27 June 2015 (JD 2457200.5)
Uncertainty parameter 0
Observation arc	28.93 yr (10,567 days)
Aphelion	3.6569 AU
Perihelion	0.7414 AU
Semi-major axis	2.1991 AU
Eccentricity	0.6628
Orbital period	3.26 yr (1,191 days)
Mean anomaly	210.20°
Inclination	3.0396°
Longitude of ascending node	82.248°
Argument of perihelion	168.88°
Earth MOID	0.0462 AU
Physical characteristics
Dimensions	1.849±0.022 km 2.25 km (calculated)
Rotation period	67.5±6 h 100 h
Geometric albedo	0.297±0.056 0.20 (assumed)
Spectral type	S
Absolute magnitude (H)	15.6

4486 Mithra, provisional designation 1987 SB, is a highly eccentric asteroid, classified as a near-Earth and potentially hazardous object. The suspected contact-binary asteroid belongs to the group of Apollo asteroids and measures about 2 kilometers in diameter. It 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.

The S-type asteroid orbits the Sun at a distance of 0.7–3.7 AU once every 3 years and 3 months (1,191 days). Its orbit is tilted by 3 degrees to the plane of the ecliptic and shows an outstandingly high eccentricity of 0.66. The potentially hazardous asteroid has an Earth minimum orbit intersection distance of 0.0462 AU. On 14 August 2000, it passed 0.0465 AU (6,960,000 km) from Earth.

Radar imaging using a delay-Doppler technique at the Arecibo and Goldstone observatories rendered a rotation period of 67.5±6 hours. Based on the radar analysis, the asteroid 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). A large number of near-Earth objects are believe to be contact-binaries.

According to the survey carried out by the NEOWISE mission of the U.S. Wide-field Infrared Survey Explorer, the asteroid's surface has a high albedo of 0.30, while the Collaborative Asteroid Lightcurve Link (CALL) assumes an albedo of 0.20, which consequently leads to a larger calculated diameter of 2.25 kilometer compared to the 1.85 kilometer determined by WISE.

The minor planet was named after Mithra, god of light in the proto-Indo-Iranian religion, that led to Mithraism, one of the last oriental mystery cults to reach the west, where it became the chief rival to and opponent of Christianity. In Asia Minor around 330 B.C. Mithra was identified with the Greek god Apollo (after whom the asteroid 1862 Apollo is named). Mithraism and Christianity have much in common: a divine lord by whom man was assured of elevation, a sacramental meal and a ritual of baptism. Many ruins of Mithraic sanctuaries were found in Europe.

External links

• NeoDys
• Radar observations and a physical model of contact binary Asteroid 4486 Mithra – Science Direct
• 3D Model Rotating image of the asteroid
• Asteroid Lightcurve Database (LCDB), query form (info)
• Dictionary of Minor Planet Names, Google books
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 4486 Mithra at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters