A 3-mile big asteroid Florence will pass safely by earth on September 1. The Florence is one of the largest near-Earth objects currently being tracked by NASA.
Florence is a stony asteroid of the Amor group, classified as a near-Earth object and potentially hazardous asteroid, approximately 5 kilometers in diameter. It was discovered on 2 March 1981 by American astronomer Schelte Bus at Siding Spring Observatory.
Florence orbits the Sun at a distance of 1.0–2.5 AU once every 2 years and 4 months (859 days). Its orbit has an eccentricity of 0.42 and an inclination of 22° with respect to the ecliptic.
Florence is classified as a potentially hazardous asteroid (PHA), due to both its absolute magnitude (H ≤ 22) and its minimum orbit intersection distance.
Asteroid Florence is among the largest near-Earth asteroids that are several miles in size. Measurements from NASA's Spitzer Space Telescope and Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission indicate it is about 4.4 kilometers in size.
"While many known asteroids have passed by closer to Earth than Florence will on September 1, all of those were estimated to be smaller," said Mr Paul Chodas, manager of NASA's Center for Near-Earth Object Studies (CNEOS).
"Florence is the largest asteroid to pass by our planet this close since the NASA programme to detect and track near-Earth asteroids began," Mr Chodas said.
This relatively close encounter provides an opportunity for scientists to study this asteroid up close. Florence is expected to be an excellent target for ground-based radar observations, NASA said.
The resulting radar images will show the real size of Florence and also could reveal surface details as small as about 10 meters.
Asteroid Florence was discovered by Schelte Bus at Siding Spring Observatory in Australia in March 1981. It is named in honour of Florence Nightingale, the founder of modern nursing.
This year's encounter is the closest by the asteroid since 1890 and the closest it will ever be until after 2500, according to the US space agency.
Florence will brighten to the ninth magnitude in late August and early September, when it will be visible in small telescopes for several nights as it moves through the constellations Piscis Austrinus, Capricornus, Aquarius and Delphinus.