(53319) 1999 JM8

(53319) 1999 JM₈

Radar image of (53319) 1999 JM8 Arecibo Observatory (Lance Benner, JPL)
Discovery
Discovered by	LINEAR
Discovery date	13 May 1999
Designations
Alternative names	1990 HD1
Minor planet category	Apollo PHA Mars crosser
Orbital characteristics
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc	9442 days (25.85 yr)
Aphelion	4.4760 AU (669.60 Gm)
Perihelion	0.97524 AU (145.894 Gm)
Semi-major axis	2.7256 AU (407.74 Gm)
Eccentricity	0.64220
Orbital period	4.50 yr (1643.6 d)
Average orbital speed	16.01 km/s
Mean anomaly	247.69°
Mean motion	0° 13m 8.508s / day
Inclination	13.856°
Longitude of ascending node	133.70°
Argument of perihelion	166.76°
Earth MOID	0.0276419 AU (4.13517 Gm)
Jupiter MOID	0.842693 AU (126.0651 Gm)
Physical characteristics
Dimensions	6.4 km
Mean radius	3.5 ± 0.7 km
Rotation period	136 h (5.7 d)
Spectral type	X
Absolute magnitude (H)	15.2

(53319) 1999 JM₈ (also written (53319) 1999 JM8) is a Potentially hazardous asteroid, near-Earth asteroid and Mars-crosser asteroid discovered by LINEAR. Radar imaging by Goldstone and Arecibo has revealed the asteroid to have an effective diameter of 6.4 km. Like the asteroid 4179 Toutatis, its rotation speed is unusually slow and possibly chaotic. It is the largest Potentially hazardous object known.

It passed closer than 0.20 AU to the Earth five times in the last century (0.033 AU in 1990), but its closest approach in the 21st century will be in 2075 at 0.256 AU.