Our next RECON event this coming Monday evening involves Centaur 12CG! A challenging component of this event is that the target will be rising low in the eastern sky. Note that this won’t give our teams a ton of time to lock on the star field.
We wanted to take this opportunity to talk for a second about the naming convention for TNOs and other minor planets. For all of our previous events, you may have noticed that objects had names like 14UT114 and 08FC76, while our event this week does not have a number at the end. Let’s break this down.
The name 12CG indicates that this object was the seventh minor planet discovered in the two week period between February 1 – February 15, 2012. The first two digits (12) represent the year of discovery and the first letter (C) indicates the half-month of discovery. The letter A is for objects discovered between January 1-15, B is for January 16-31, and C for February 1-15. Note that the letter “I” is skipped, resulting in Y representing the 24th half-month of December 16-31. The second character (G) is the order of discover, with A being the first object in that period and G being the seventh. Here again, the letter “I” is not used, so this naming convention can be used for the first 25 objects discovered in a given half-month.
So why do most TNOs end with a number while 12CG does not? After the 25 object discovered in a half month,a number is indexed at the end of the name and second alpha character cycles back through the alphabet. Thus, while the 25th discovered object between February 1 – February 15 would be 12CZ, the 26th object would be named 12CA1, and the 27th would be 12CB1.
Ready to quiz yourself? Try 14UT114:
- 14U = Object was discovered between October 16-31, 2014
- T114 = We’ve cycled 114 times through the 25 letters of the alphabet (minus the letter “I”), or 114 x 25 = 2,850 times. The letter T indicates it is the 19th object after these 2,850 prior objects. So the object is the 2,869th discovery of this half-month.
How about 08FC76? . . . yup, the 1,903rd minor discovered between March 16-31, 2008. For more information and clarification, check out the following Wikipage on provisional designation in astronomy.
Good luck to all of our teams this Monday evening!!!