2017 BS₅

July 23, 2017 flyby of Earth
Discovery[1][2]
Discovered by	ATLAS (T05)
Discovery site	Haleakala Obs.
Discovery date	25 January 2017
Designations
MPC designation	2017 BS5
Minor planet category	Apollo · NEO[1]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 1
Observation arc	(190 days)
Aphelion	1.0231 AU
Perihelion	1.0078 AU
Semi-major axis	1.0154 AU
Eccentricity	0.0075
Orbital period (sidereal)	1.02 yr (374 days)
Mean anomaly	204.63°
Mean motion	0° 57m 47.52s / day
Inclination	11.232°
Longitude of ascending node	120.84°
Argument of perihelion	15.577°
Earth MOID	0.0070 AU · 2.7 LD
Physical characteristics
Dimensions	40–90 meters
Absolute magnitude (H)	24.1[1]

In the astronomy of the Solar System, 2017 BS₅ is a sub-kilometer asteroid, classified as near-Earth object that belongs to the Apollo group. It measures approximately 40–90 meters.^[3] During a close approach to Earth, it was first observed 25 January 2017, by the ATLAS survey at Haleakala Observatory, Hawaii, United States.^[2]

Orbit

2017 BS₅ has a low-eccentricity orbit with a semi-major axis only slightly larger than that of Earth. It orbits the Sun at a distance of 1.008–1.023 AU once every 1.02 years (374 days). Its orbit has an eccentricity of 0.01 and an inclination of 11° with respect to the ecliptic.^[1] It has an Earth minimum orbital intersection distance of 0.007 AU (1,050,000 km), which corresponds to 2.7 lunar distances.^[1] The body is too small to be classified as a potentially hazardous asteroid.

July 2017 flyby

On 23 July 2017, it passed by within 3.15 lunar distances.^[4] Seen from the Earth it passed straight north to south from Draco south into Scorpio. With its 1.023 year orbit it has a synodic period of 43 years with the earth, so it will flyby the Earth every 43 years or so. JPL Small-Body Database's simulator show the previous flyby in July 1973 and next one will be in July 2061.