|NEO 68350 RECOVERED|
On July 18, 2001 during a routine asteroid search in a crowded Milky Way starfield,
we inadvertently recovered a Mars-crossing NEO (Near Earth Object).|
NEO's are of particular interest to astronomers because of the possibility of collision with Earth. Several professional observatories are funded specifically to discover and track these objects. Amateur astronomers have a difficult time finding NEO's because they move so quickly, and are often lost before their orbits are determined. They can become unrecoverable within just a day or two after discovery.
|This is a composite of the 6 images that revealed 2001 MK3. The images are overlaid in alignment with the fixed stars. A typical MBO would appear as a pair of dots. This fast-mover actually shows up as a triplet within each ellipse. Also, an MBO would have moved only halfway from ellipse #1 to ellipse #2 within the elapsed hour.|
That evening, we took 3 exposures near the ecliptic at the opposition point. About an
hour later we re-imaged the same area. The next day, we digitally processed the images and
"stacked" them. To our surprise, 2 small groups of 3 dots appeared.
We had spotted an object so close to Earth that it was moving noticeably within just one (1)
We immediately turned in our sighting of this 18.2 mV object to the MPC and soon found that we had recovered 2001 MK3, an NEO that had been discovered and tracked for 9 days at the end of June, 2001. In the 3 weeks before we spotted it, the NEO had deviated 200 arcseconds from it expected position. Our recovery improved its orbit, allowing other observations to be linked. The object was then found in old data back to 1955!
This 4 km object, which is now numbered, is a Mars-crosser because it varies 1.256 AU to 2.083 AU from the Sun. With a 2.16-year orbital period, it makes almost exactly 6 revolutions every 13 years. When it reaches opposition near July 2 of any given year, it is near aphelion and reaches only magnitude 19. However, favorable (perihelic) oppositions occur in early January, when the object may brighten to magnitude 14, as at the 1955 sighting. Its oppositions usually occur in star-crowded Milky Way fields.
Its orbit is inclined a steep 29.6 degrees, which has probably kept it from discovery for so long.