37655 Illapa

37655 Illapa (provisional designation 1994 PM) is a carbonaceous asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.5 kilometers in diameter. It was discovered, on 1 August 1994, by American astronomer couple Carolyn and Eugene Shoemaker at the Palomar Observatory in California, United States.^[1]

Illapa

Discovery[1]
Discovered by	C. S. Shoemaker E. M. Shoemaker
Discovery site	Palomar Obs.
Discovery date	1 August 1994
Designations
MPC designation	(37655) Illapa
Named after	Illapa (Inca mythology)[1]
Alternative designations	1994 PM
Minor planet category	NEO · Apollo · PHA[1]
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc	7645 days (20.93 yr)
Aphelion	2.5901 AU (387.47 Gm)
Perihelion	0.36604 AU (54.759 Gm)
Semi-major axis	1.4780 AU (221.11 Gm)
Eccentricity	0.75235
Orbital period (sidereal)	1.80 yr (656.34 d)
Mean anomaly	299.48°
Mean motion	0° 32m 54.564s / day
Inclination	18.002°
Longitude of ascending node	139.70°
Argument of perihelion	303.72°
Earth MOID	0.0235523 AU (3.52337 Gm)
Physical characteristics
Mean diameter	0.792–1.772 km (est.)[2] 1.5 km (generic at 0.057)
Synodic rotation period	2.6556 h[1]
Spectral type	C[3]
Absolute magnitude (H)	17.9[1]

Orbit and classification

On 16 August 2003, Illapa made a close approach to Earth of 0.025037 AU (3,750,000 km; 2,330,000 mi).^[4]

Physical characteristics

Illapa has an estimated diameter of 0.8 to 1.8 kilometers for an assumed geometric albedo between 0.20 and 0.04.^[2] For an assumed albedo of 0.057, which is typical for carbonaceous C-type asteroids, and an absolute magnitude of 17.9,^[1] the asteroid has a calculated mean diameter of 1.5 kilometers. The body has a short rotation period of 2.6556 hours.^[1]

Naming

This minor planet was named after Illapa (Apu Illapu), the thunder or weather god from Inca mythology.^[1]