Asteroid 2017 TF5 flew past Earth at 0.73 LD, 4 days before discovery

A newly discovered asteroid designated 2017 TF5 flew past Earth at 0.73 LD (~280 320 km / 174 182 miles) at 07:40 UTC on October 10, 2017, 4 days before it was discovered. This is the 38^th known asteroid to flyby Earth within 1 lunar distance since the start of the year.

2017 TF5 belongs to the Apollo group of asteroids, those whose orbits cross the Earth's orbit similar to that of 1862 Apollo (a > 1.0 au; q < 1.017 au). It was discovered by Mt. Lemmon Survey on October 14, 2017, 4 days after its close approach to Earth.

Its estimated diameter is between 31 and 68 m (101 and 223 feet).

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

The flyby took place two days before long-awaited asteroid 2012 TC4. 

This is the 38^th known near-Earth asteroid to flyby Earth within 1 lunar distance since the start of the year, including 2012 TC4. It flew past Earth at a speed (relative to the Earth) of 22.82 km/s.

Reference:

Asteroid 2012 TF5 at Minor Planet Center; CNEOS

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 gray. The blue arrow points in the direction of Earth's motion and the yellow arrow points toward the Sun. Credit: Minor Planet Center