 |
| This composite image of the
primordial contact binary Kuiper Belt Object 486958 Arrokoth =2014 MU69 – featured on the cover of the May 17 issue of the journal
Science – was compiled from data obtained by NASA's New Horizons
spacecraft as it flew by the object on Jan. 1, 2019. The image combines
enhanced color data (close to what the human eye would see) with
detailed high-resolution panchromatic pictures. https://en.wikipedia.org/wiki/486958_Arrokoth#/media/File:UltimaThule_CA06_color_vertical.png |
Many times when there is a story about a small solar system body, one of the questions that come up is with its "name." Quite often, people will try to use designation and name as if they are interchangeable, which can lead to lead to confusion. Let us go into some background, from discovery to naming. Observing is done by taking several images of the night sky and looking for moving objects. When observing small solar system bodies, observations are submitted to the Minor Planet Center(MPC), the worldwide data clearinghouse. All observations must be tag with the correct designation for the object.
When observers find something new, they use an "observer-assigned temporary designation." Temporary designations are also used when observers are not taking the time to identify objects, or there is doubt. Temporary designations must be unique to each "object" each "night." MPC's computer checks to see if observations with a temporary designation belong to known objects, other new discoveries, and make identifications. After two nights of observations, a "new" object is assigned a provisional designation. The provisional designation gives the year, the half-month, and the order of discovery(i.e., 2014 AA). If an object is "new" and maybe a NEO, it becomes a NEOCP object. NEOCP objects are posted to the NEO Confirmation Page using the "observer-assigned temporary designation" for rapid worldwide followup. NEOCPs may take longer than two nights to get a provisional designation.
The assignment of a provisional designation does not mean we know we know everything about an object. An object, because it is out of range, may go unobserved for many years. It is also possible the object was observed at an earlier opposition(apparitions). As more observations are taken, the orbit improves. With the improvements in orbit, it may become possible to make links and show one object is another already known object. So, therefore, an object may have more one provisional designations(principal and alternate designations).
After at least four oppositions(for main-belt), "two or three well-observed oppositions" for NEOs, and when uncertainty is low enough, an object is given a permanent designation(a number). At this time, discovery credit is assigned. After being numbered, objects become eligible to be named. It should be noted that debases will show the object's designations(permanent, provisional, alternate).
The discoverer, as defined by MPEC 2010-U20, may suggest a name within ten years after numbering. Names must follow some rules, and discoverer writes a brief naming citation explaining the name. Names and citations voted on by the fifteen-member The Working Group for Small Bodies Nomenclature "Names become official when they are published in the Minor Planet Circulars. Note that the CSBN condemns the preannouncement of names, even if any such preannouncement indicates that a name is only a proposal." (see Guide to Minor Body Astrometry)
After an object is named, it keeps its permanent(number) and provisional designations. Objects can be searched for by name, number, or provisional designations; however, observer-assigned temporary designations are not kept. The number is used when reporting astrometry to the MPC. When observations are published, they are listed by number or provisional designation(not by name).
Names are useful; Arrokoth is more comfortable to say than (486958) 2014 MU69. If an object is named, the name can tell a reader something about the class of the object given that there naming rules for each class. Of 851,094 known small solar system bodies 541,155 have been numbered, and ~22,000 have been named. One can spend hours reading naming citations. Fact that an object is number tells you it is well observed with low uncertainty the sad thing is many times some reporters will not use the number in stories which leaves out useful information.
(486958) 2014 MU69 was set to be a New Horizons Flyby Target however it was not "named" yet so the public asked help come up with "Nickname" until "[a]fter the flyby, NASA and the New Horizons project plan to choose a formal name to submit to the International Astronomical Union, based in part on whether MU69 is found to be a single body, a binary pair, or perhaps a system of multiple objects. The chosen nickname will be used in the interim." -- Help Nickname New Horizons' Next Flyby Target (November 6, 2017) also see Introducing "Ultima Thule": NASA's Ultimate Destination in the Kuiper Belt! It was state plan was to work with International Astronomical Union on a permanent name after the flyby.
(486958) 2014 MU69 was set to be a New Horizons Flyby Target however it was not "named" yet so the public asked help come up with "Nickname" until "[a]fter the flyby, NASA and the New Horizons project plan to choose a formal name to submit to the International Astronomical Union, based in part on whether MU69 is found to be a single body, a binary pair, or perhaps a system of multiple objects. The chosen nickname will be used in the interim." -- Help Nickname New Horizons' Next Flyby Target (November 6, 2017) also see Introducing "Ultima Thule": NASA's Ultimate Destination in the Kuiper Belt! It was state plan was to work with International Astronomical Union on a permanent name after the flyby.
On 2019 November 8, Minor Planet Circulars 117229-118222 was published with a Official name and naming citation ---(486958) Arrokoth = 2014 MU69 also see New Horizons Kuiper Belt Flyby Object Officially Named 'Arrokoth' Then stories of name changes started to fly around the internet
