The Asteroid Florence3122

By Mohammad Hassan

BACKGROUND

• Asteroid 3122 Florence is a stony trinary asteroid of the Amor group.• It was discovered on March 2nd 1981 by Astronomer Schelte J. ”Bobby” Bus at Siding Spring

Observatory. It was named in honor of Florence Nightingdale, the founder of modern nursing.• It has an approximate diameter of 5 kilometers. It also orbits the Sun at a distance of 1.0-2.5

astronomical unit once every 2 years and 4 months (859 days).• Florence rotates once every 2.4 hours, a result that was determined previously from optical

measurements of the asteroid’s brightness variations.• THE MOST FASINATING THING IS THAT IT HAS TWO MOONS, HENCE WHY IT IS A PART OF THE

AMOR GROUP.• The reason why this Asteroid 3122 Florence is important is because it is a near-earth object

with the potential of hitting the earth in the future time.

Concerns?• Florence 3122 was classified as a potentially hazardous object because of its minimum orbit

intersection distance (less than 0.05 AU). This means that Florence 3122 has the potential to make close approaches to the Earth. • Another thing to keep in mind was that Florence 3122 minimum distance from us was 7 millions of km,

about 20 times farthest than our moon.

What actually happened?• On September 1st, 2017, Florence passed

0.047237 AU from Earth. That is about 7,000 km or 4,400 miles.

• From Earth’s perspective, it brightened to apparent magnitude 8.5. It was also visible in small telescopes for several nights as it moved from south to north through the constellations.

• This asteroids most recent flyby was on August 29, 1930, with a distance of 0.05239 AU. The next one will be on September 2, 2057, at a distance of 0.049952 Au’s.

TWO MOONS??!!??• During the flyby, radar

observations showed that Florence has two moons. There is an inner and outer moon.

• The inner moon has an estimated diameter of 180 to 240 meters. The outer moon is somewhere between 300 to 360 meters.

• The inner moon has a period of approximately 7 hours, on the other hand, the outer moon has a period of about 21-23 hours.

• Each moon is elongated and tidally locked to the main body, aka Florence.

 Image via NASA/JPL Center for Near-Earth Object Studies.

Why TWO MOONS (satellites)??

• There is no definite answer to this question, but there is an idea.

• The two moons probably formed as a loose material spun away from the main body as its rotation accelerated due to the YORP effect.

• YORP effect is the change in the rotation state (spin period) of an asteroid in heliocentric orbit due to the scattering of solar radiation off the surface of the body and emission of the body’s own thermal radiation.

Videos and Images of Asteroid 3122 Florence• The labeled dates on this chart mark the

asteroid’s location at 11 pm. (Eastern Daylight Time)

http://earthsky.org/todays-image/photos-asteroid-3122-florence-aug-sep-2017

https://www.virtualtelescope.eu/2017/09/04/potentially-hazardous-asteroid-3122-florence-online-event-an-epic-success/

Diagram via SkyandTelescope.com.

Recent asteroids near Earth• This chart shows the cumulative

number of known Near- Earth asteroids versus time. These asteroids are larger than 140 m in size. It is estimated that about 93% of these are bigger than 1 km.

ASTEROID DEFENSE?

• NASA has build an office in 2016: The planetary Defense Coordination Office. It is tasked with helping find dangerous asteroids and comets, and its leading US government efforts to develop a plan to respond to an actual impact threat.

• Some advancements made to deal with asteroids are one a kinetic impactor, which is, a spacecraft that slams into the asteroid to move its orbit. The second thing is a gravity tractor, which is, a spacecraft gravity pulling the asteroid. Third is laser ablation, vaporizing rock to create jets that push the asteroid, and the last thing, final resort, is nuclear disruption, rapid vaporizing of rocks on one part of an asteroid.

Work Cited

• https://www.virtualtelescope.eu/2017/09/04/potentially-hazardous-asteroid-3122-florence-online-event-an-epic-success/

• http://www.cnn.com/2017/08/31/us/asteroid-florence-earth-fly-by-trnd/index.html• http://earthsky.org/todays-image/photos-asteroid-3122-florence-aug-sep-2017• http://earthsky.org/astronomy-essentials/asteroid-1981-et3-3122-florence-pass-earth-2017-binoculars• http://www.skyandtelescope.com/observing/see-asteroid-florence-fly-by-earth-this-week/• https://en.wikipedia.org/wiki/3122_Florence• https://www.space.com/51-asteroids-formation-discovery-and-exploration.html

ANY QUESTIONS AND OR COMMENTS?