Asteroid 2018 BF3 flew past Earth at 0.63 LD, 6th in 4 days

A sixth known near-Earth asteroid in just 4 days flew past Earth within 1 lunar distance on January 19, 2018. The latest asteroid was designated 2018 BF3 and it flew past Earth at a distance of 0.63 LD / 0.00162 AU (~242 348 km / 150 588 miles) at 03:00 UTC. This was also the third known asteroid to flyby Earth within 1 lunar distance on January 19. 

Asteroid 2018 BF3 belongs to the Apollo group of asteroids. It was first observed at Catalina Sky Survey on January 20, a day after its closest approach.

This asteroid has an estimated diameter between 18 and 40 m (59 – 131 feet) and it flew past Earth at a speed (relative to the Earth) of 13.47 km/s.

[ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Close-Approach Data ]

This is the 6^th and largest asteroid to flyby Earth within 1 lunar distance in just 4 days and the 3^rd in just 1 day. There were only 2 occasions in 2017 when 3 known asteroids flew past Earth within 1 LD; it happened on March 20 and September 20.

Size comparison: Asteroid that exploded some 29.7 km (18.5 miles) above Russian city of Chelyabinsk at 09:20 YEKT (03:20 UTC) on February 15, 2013, damaging over 3 000 buildings and injuring over 1 500 people (mostly by broken window glass), had an estimated size of approximately 20 m (65 feet). Its light was brighter than the Sun, visible up to 100 km (62 miles) away.

Chelyabinsk asteroid, officially named Chelyabinsk meteorite, was undetected before its atmospheric entry, in part because its radiant was close to the Sun.

Check your speakers. Loud asteroid explosion on video. 

In the hours following the visual meteor sighting, a 6-meter (20 feet) wide hole was discovered on Lake Chebarkul's frozen surface and scientists from the Ural Federal University collected 53 samples from around the hole the same day it was discovered.

A large number of small meteorites fell on areas west of Chelyabinsk and local residents and schoolchildren located and picked up some of them, many located in snowdrifts, by following a visible hole that had been left in the outer surface of the snow. 

Since the start of the year, we've discovered a total of 7 asteroids that flew past Earth within 1 lunar distance. Since January 1, 2017, that number now stands at 60.

<1 lunar distance asteroid flybys since the start of the year:

2018 BX – January 19 @ 23:00 UTC. Distance: 0.73 LD | 0.00188 AU. Size: 4.3 – 9.5 m

2018 BC – January 19 @ 20:23 UTC. Distance: 0.73 LD | 0.00189 AU. Size: 3.5 – 7.9 m

2018 BF3 – January 19 @ 03:00 UTC. Distance: 0.63 LD | 0.00162 AU. Size: 18 – 40 m

2018 BD – January 18 @ 15:43 UTC. Distance: 0.10 LD | 0.00026 AU. Size: 2.5 – 5.5 m. Note: closest

2018 BR1 – January 16 @ 13:22 UTC. Distance: 0.34 LD | 0.00088 AU. Size: 3.3  – 7.5 m

2018 BW – January 15 @ 15:13 UTC. Distance: 0.43 LD | 0.00112 AU. Size: 6.5  – 14 m

2018 AH – January 2 @ 04:25 UTC. Distance: 0.77 LD | 0.00199 AU. Size:  85 – 190 m. Note: Largest

Reference:

Asteroid 2018 BF3 at Minor Planet Center; at CNEOS

Featured image: Featured image: The green line indicates the object's apparent motion relative to the Earth, and the bright green marks are the object's location at approximately one-hour intervals. The Moon's orbit is grey. The blue arrow points in the direction of Earth's motion and the yellow arrow points toward the Sun. Credit: Minor Planet Center.