2019 BZ3

2019 BZ₃ is a very small near-Earth asteroid of the Apollo group, approximately 6 meters (20 feet) in diameter. It was first observed by the Mount Lemmon Survey on 28 January 2019, just hours after the asteroid's sub-lunar flyby of Earth at less than 0.12 lunar distance.^[1][4]

2019 BZ₃

Orbit of 2019 BZ3, before and after 2019 flyby with 30 day motion
Discovery[1]
Discovered by	MLS
Discovery site	Mount Lemmon Obs.
Discovery date	28 January 2019 (first observed only)
Designations
MPC designation	2019 BZ3
Minor planet category	NEO · Apollo[1][2]
Orbital characteristics[2]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 7[2] · 5[1]
Observation arc	8 days
Aphelion	3.6251 AU
Perihelion	0.9591 AU
Semi-major axis	2.2921 AU
Eccentricity	0.5815
Orbital period (sidereal)	3.47 yr (1,268 d)
Mean anomaly	30.064°
Mean motion	0° 17m 2.4s / day
Inclination	10.631°
Longitude of ascending node	127.44°
Argument of perihelion	338.22°
Earth MOID	0.0004575 AU (0.18 LD)
Physical characteristics
Mean diameter	6 m (est. at 0.15)[3]
Apparent magnitude	17.9 (brightest)[1]
Absolute magnitude (H)	28.8[1] 28.719[2]

Orbit and classification

Path across sky, 30 minute motion

Hourly motion moon's orbit

2019 BZ₃ is an Apollo asteroid, the largest subgroup of near-Earth objects. It orbits the Sun at a distance of 0.96–3.6 AU once every 3 years and 6 months (1,268 days; semi-major axis of 2.29 AU). Its orbit has a high eccentricity of 0.58 and an inclination of 11° with respect to the ecliptic.^[2] The body still has a high orbital uncertainty of 5 and 7, respectively.^[1][2] Its observation arc of only 8 days begins with its official first observation at Mount Lemmon Observatory on 28 January 2019.^[1]

Close approaches

2019 BZ₃ has an Earth minimum orbital intersection distance of 0.000457 AU (68,000 km), which corresponds to 0.18 lunar distances (LD).^[2] Due to its very small size, however, 2019 BZ₃ is not a potentially hazardous asteroid, which are required to be approximately 140 meters (460 ft) in diameter, that is, to be brighter than an absolute magnitude of 22.

Flybys

On 27 January 2019 at UTC 23:29, 2019 BZ₃ passed Earth at a nominal distance of 48,130 km (0.125 LD) with a relative velocity of 11.37 km. Six hours later, it flew by the Moon at 350400 km.^[2][4] The object's next close approaches will occur on 17 December 2025 at a much greater distance of 56 LD (0.143 AU), and on 29 January 2085 at 5.5 LD (0.0142 AU).^[5]

Numbering and naming

This minor planet has not yet been numbered by the Minor Planet Center and remains unnamed.^[1]

Physical characteristics

2019 BZ₃ has an undetermined spectral type. Based on a generic magnitude-to-diameter conversion, the asteroid measures approximately 6 meter in diameter for an assumed albedo of 0.15 and absolute magnitude 28.8.^[3] The estimated diameter may vary between 5 and 10 meters depending on whether an albedo for a dark carbonaceous (0.05) or a bright stony (0.25) asteroid is assumed.^[3]

See also

• List of asteroid close approaches to Earth in 2019