NEO asteroid discoveries update
reported by meteordetective
NASA reporting period "E", for 2016, concluded yesterday. As of 00:00 GMT, today, 16th March, period "F" began - but I thought it was worth delving-in to this topic and explaining, for those that do not know, how this system works...and also list the results for period "E", which just concluded.
NASA split each month into 2 time periods: 1st-15th and 16th-End Of Month (28/29/30/31). NASA use a slightly counter-intuitive and long-winded method to numerate the various discoveries (rather than an intuitive decimal system).
The basic premise is that a decimal-equivalent (1-25) cycle of A-Z (omitting "I") is used to 'count' the discovered asteroids - so that the 1st asteroid is "A", the 2nd is "B" and the 25th asteroid is "Z", and hence you may see an asteroid with the designation "2016 AA." This translates to:
Period = "A" (the first A in the ID/designation)
Asteroid count = 1 (the second A in the ID/designation).
Using this system, the next asteroid discovered would be 2016 AB, then 2016 AC and so on. If and when the asteroid discovery count exceeds 25 (which happens mostly each and every period), the number of (0-25) cycles used-up is displayed to the right.
Here's a short demonstration using an imaginary asteroid designated as "2016 AA100" - which equates to:
Period = A
Asteroid count = A (i.e. 1)
Number of (1-25) cycles used-up = 100
This translates to a decimal equivalent of object number 2,501 = (1 + (100 x 25)).
So, 2016 AA100 would be the 2,501st asteroid discovery of period "A" (the first two weeks of January), of 2016.
The next discoveries, in sequence, would be 2016 AB100 (decimal = 2,502), 2016 AC100 (decimal = 2,503) and 2016 AD100 (decimal = 2,504)...and so on until arriving at 2016 AA101 (decimal = 2,526) and beyond.
With this explanation provided, it will hopefully make sense that the latest announced discovery of 2016 period "E" was 2016 EB158 - which equates to the 3,952nd discovery of period "E".
(This may be superseded over the next few days, if there are any objects from period "E" still being processed - post observation. It is also important to note that the maximum 'range / distance' for including asteroids in this system is 0.5 AU, or 1/2 the mean distance to the Sun).
Of these 3,952 new (<0.5AU) discoveries (for the first 2 weeks of March), 33 of them came within 10 LD (Lunar Distances) of Earth.
4 of these had a close-approach of less than 1LD, 15 were in the 1-5LD range and 14 were in the 5-10LD range.
Spring / Vernal Equinox
It is worth mentioning that (Astronomical) Spring begins with the Vernal Equinox at 09:50 GMT on 20th March, when the Sun crosses the ecliptic/equator, heading North, and also crosses the so-called "First Point Of Aries" (which is actually in Pisces...due to precession). The Sun's Right Ascension will be 0 hours, 0 minutes, 0 seconds (longitudinal position) and its Declination (latitudinal position) will be 0 degrees, 0 minutes, 0 seconds.
252P/Linear makes its close-approach of 13.9LD at 13:15 GMT on the 21st March.
As you might have noticed, fireball / meteor activity has been very quiet for the preceding few days, but keep watching (not when you're driving / in charge of a vehicle etc)...just in case. March 22nd is supposedly the time of sighting for the March Geminids, so perhaps there will be something to see in the night sky.
2016 The THIRD Year of "CERTAIN Uncertainty" ™ / Meteors, Asteroids, Comets, and MORE!!