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    The document below is the text of the comet-naming guidelines as adopted in 2003 March by the International Astronomical Union's Committee on Small Body Nomenclature (CSBN).

    Since this was adopted, the following changes have occurred:

    • The CSBN was renamed as the Working Group on Small Body Nomenclature (WGSBN);
    • The WGSBN is now under IAU Division F;
    • CBAT is no longer an IAU center.
    The original version of this document has been updated below to reflect these changes.

      Working Group on Small Bodies Nomenclature (IAU Division F) = WGSBN
        [in the following, the WGSBN means also any other appropriate IAU
        committee that may replace the WGSBN in the future for the purposes
        of deciding comet-nomenclature issues]
      Minor Planet Center = MPC
         Comets did not become routinely named for their discoverers until
     the 20th century.  In the 19th century, names were generally used for
     short-period comets only after their second apparition;  single-apparition
     short-period comets and long-period comets were generally referred to by
     designations (with names sometimes, though not with much consistency,
     given parenthetically).
         In recent years, the comet-naming process has been impacted by
     several wide-field CCD surveys conducted by professional teams.  It is
     therefore appropriate to write down guidelines for the naming of comets to
     make the process as simple and fair as possible.  Though guidelines have
     been drafted previously by IAU Commission 20 members in recent years, this
     aims to replace those guidelines by starting anew, by creating guidelines
     that are even simpler and more fair.  These guidelines may need to be
     revised by the WGSBN, as special circumstances warrant.
          The MPC receives astrometry, makes identifications and computes comet
     orbits, and makes collections of observations and orbits available to the
     community.  In recent practice, comet names are announced on Minor Planet
     Electronic Circulars after a reasonable orbit has been determined, in an
     effort to prevent re-naming of lost comets.  The MPC consults with the
     WGSBN on non-routine naming matters, in which some interpretation of the
     following guidelines is deemed appropriate.
    Guideline 1:  Regarding proper reporting of discoveries.
        1.1  Comets normally receive their names on the basis of information
           available to the MPC at the time of first official announcement
           of the discovery.  The discovery observation (and thus the
           discoverer) is taken to be that which permits the MPC to issue
           reasonable requests for confirming observations (usually via
           the MPC's NEO Confirmation Page.
        1.2  Comets are generally considered no longer available for additional
           recognized discovery claims once the call for confirmation has been
           widely issued (e.g., e-mail or World Wide Web posting) by the MPC.
        1.3  Independent discoveries of a comet that are reported to the MPC
           after the issuance of the announcement MPEC are usually not
           considered in the naming process, unless:
             (a) it can be shown unambiguously that the discovery claim
                 in question was made before any outside knowledge could
                 have been available to the claimant; and
             (b) that the comet has not yet been named; and
             (c) there are not already more than two names to be given
                 to the comet in question.
        1.4  The time of comet discovery is taken to be the time of the first
           detection visually or the time that the image was taken upon which
           the discovery was made.
    Guideline 2:  Regarding discoverers.
        2.1  Comets are to be named for their individual discoverer(s) if at all
           possible.  This means using the last (family) name of the
        2.2  Sometimes, however, team names are more appropriate.
             (a) A discoverer is defined here as the person(s) who first detect(s)
                 the comet (visually, or on a photograph or electronic image).
                 He or she is responsible for obtaining and communicating to the
                 MPC (possibly via a responsible third party) accurate information
                 on the comet's positions and physical appearance.
             (b) Although past comets have borne the names of three (and, on rare
                 occasions, more) discoverers, it is preferable to keep the limit
                 to two names if at all possible; more than three names are to be
                 avoided except in rare cases where named lost comets are
                 identified with a rediscovery that has already received a new
             (c) When there are two (or more) independent discoveries of a comet,
                    (1) the discoverers' (or their teams') names are to be listed
                        in the chronological order in which each discoverer
                        (or team) found the comet,
                    (2) each individual name is to be separated by a hyphen
                        (but family surnames with two or more words separated
                        by either spaces or hyphens are to be distinguished
                        in comet names by single spaces only between each surname
                        word -- although, for simplicity, the discoverer shall
                        in such cases also be given the option to choose one
                        main word from his or her name to represent the surname
                        on the comet, with such choosing strongly encouraged),
                    (3) there is to be no more than one name on that comet
                        from a single observing location or program (excepting
                        the possibility of lost comets being rediscovered,
                        as noted in Guideline 5, below).
             (d) Observers and observing programs (or their representatives)
                 cannot require the IAU to use any specific name.  The final
                 naming process is the sole discretion of the MPC and the WGSBN
                 in accordance with these guidelines.  For observing programs
                 consisting of more than two people, the established
                 team/program name will generally be used for the comet name
                 unless Guideline 3.4(a)(2), below, is satisfied.
        2.3  Occasionally a very bright comet (usually near the sun) suddenly
           becomes visible to many observers worldwide nearly simultaneously
           as a naked-eye object.  In some of these situations, comets do not
           receive the name(s) of any discoverer(s) but rather a "generic" name
           such as "Great Comet" or "Eclipse Comet".
     [Examples:  C/1997 J2 (Meunier-Dupouy), 57P/du Toit-Neujmin-Delporte,
                 76P/West-Kohoutek-Ikemura, 105P/Singer Brewster,
                 C/1882 R1 (Great September Comet), C/1910 A1 (Great January
                 Comet), C/1947 X1 (Southern Comet), C/1948 V1 (Eclipse Comet)]
    Guideline 3:  Regarding teams of discoverers.
        3.1  Nowadays, there are very frequently teams of professional, and even
           amateur, astronomers (as opposed to individuals) who find comets in
           the course of their observing.  It is required and presumed that
           full and truthful details concerning discovery circumstances from
           teams of discoverers will be given in the initial discovery report.
        3.2  Since most discoveries involve teamwork (in the broad sense that
           confirmation and necessary orbit work is generally done by people not
           even at the same location as the discoverer), a team is here more
           narrowly defined as a group of astronomers who are formally organized
           with certain instrumentation to seek and find celestial objects
           including comets.
        3.3  If an acceptable one-word team name (including an acronym for a
           longer team name that is acceptable to the WGSBN) is submitted for the
           observing program, this name can be used for the comet.
        3.4  If there is no team name, either the comet shall be named for the
           person who actually found the comet or the comet may receive no
           name at all.
             (a) Individual names of team members.
                    (1) In no case shall a comet contain the name of more than
                        two people from the same observing program.  If there is
                        no other independent discovery, it is acceptable to have
                        the names of two people from the same program on a comet,
                        if and only if:
                          (A) there are only two team members,
                          (B) both were directly involved in the discovery (that
                             is, involved in making the discovery observation
                             and/or first identifying the comet's image), and
                          (C) their last (family) names are not identical.
                    (2) If a team (with more than two members) supplies
                        satisfactory written testimony that a single team
                        observer did the work to find the comet and note its
                        cometary activity, measure its position and magnitude
                        (or monitor an automatic computer program that does so),
                        and report this information, then it is acceptable for
                        a comet so discovered by a team program to have that
                        single individual's name on the comet instead of the
                        program name.
                    (3) The same name is not to be used twice on the same
                        comet, even if two discoverers share the same last name.
             (b) Comets that are discovered from data or images made public
                 through printed publication or electronic posting (e.g.,
                 World Wide Web) are not eligible for individual names of
                 people and generally will not be named unless there is
                 an established program name for the origin of the images.
                 Such discoverers are considered members of the "team".
     [Examples:  C/1977 V1 (Tsuchinshan), C/1997 B3 (SOHO), C/1999 S4 (LINEAR),
                 C/1999 T1 (McNaught-Hartley), P/2000 C1 (Hergenrother),
                 P/2000 Y3 (Scotti), C/1992 U1 (Shoemaker)]
    Guideline 4:  Regarding cometary nature that is not immediately noticed.
        4.1  It frequently happens that a comet is found by (a) discoverer(s)
           --- whether a single individual, two individuals working together,
           or a team --- who cannot detect cometary activity with the equipment
           that he/she/they possess.  Such an object may therefore be assumed
           to be a minor planet and so designated when two or more nights'
           worth of observations are available to the MPC (or posted, for example
           -- prior to being designated -- on the MPC's NEO Confirmation webpage).
        4.2  If an observer (whether an individual or a team) who is not the
           original discoverer of the "minor planet" finds that an "asteroidal"
           object has a cometary appearance, and if such cometary appearance is
           confirmed, both the original discoverer of the "minor planet" and the
           identifier of the cometary nature may be credited in the name of the
           comet, subject to the following prerequisites:
             (a)  This dual recognition in the name will occur only when
                there has been no prior suspicion of the unusual nature of the
                object; if the object was listed on the "NEO Confirmation Page"
                or had an unusual orbit published prior to identification of
                cometary appearance, the identifier of the cometary nature will
                not be eligible for inclusion in the name.
             (b)  If no prior suspicion of unusual nature is suspected, the
                name of the newly recognized comet can consist of two parts:
                one part derived from the name of the original discoverer of the
                "minor planet", and the other part derived from the name of the
                discoverer of the cometary nature.  EACH PART of the name
                would, however, be subject to the following conditions:
                     (1) Only one name (either individual or team) is
                       permitted.  If the "minor planet" was credited jointly
                       to two individuals, only one of these names can be used.
                     (2) If the original discoverer of the "minor planet" is a
                       team, the team cannot suggest that an individual
                       team-member's name be used.
        4.3  If follow-up observations performed by (an) observer(s) other
           than the original discoverer of a reportedly "asteroidal" object show
           the object to be a comet (that is, showing a coma and/or tail),
           -- and the provisos of 4.2 do not apply -- the comet may
           receive a single name of the original discoverer (individual or team).
        4.4  If the minor-planet designation was published before the realization
           is made that the object is a comet, the comet will retain the
           minor-planet designation.  Otherwise, a new comet designation will
           be assigned.
        4.5  If the object receives a permanent minor-planet number prior to its
           recognition as a comet, it shall be accorded "dual status".  As such,
           it both retains the permanent minor-planet number and receives a new
           periodic-comet number.
             (a) If the numbered "minor planet" has already received a name, the
               comet should inherit this name.
             (b) If the "minor planet" has not yet received a name, a new name for
               the comet will be assigned according to these guidelines.  The same
               new name will also be used for the "minor-planet" numbering, noting
               that minor-planet names must be unique.
     [Examples:  P/1997 B1 (Kobayashi), P/1999 DN3 (Korlevic-Juric),
                 C/2000 WM1 (LINEAR); 95P = (2060) Chiron,
                 107P = (4015) Wilson-Harrington, 133P = (7968) Elst-Pizarro;
                 P/2001 BB50 (LINEAR-NEAT)]
    Guideline 5:  Regarding changes in comet names.
        5.1  The MPC/WGSBN has the option occasionally, in the interest
           of fairness and/or simplicity, to change the name of a rediscovered
           lost comet or in other complicated cases involving comet names (such
           as names found later to be spelled incorrectly or be missing
           diacritical marks, etc.).  However, such changes will be made only
        5.2  Numerous one- or multi-apparition short-period comets remain lost
           due to highly uncertain orbital elements (from poor sets of
           observations).  Sometimes such "lost" comets are rediscovered, and
           occasionally the identification of the past apparition(s) is not made
           until after a new name is assigned; though efforts are made to search
           for identifications before naming of a new comet is made, this is
           not always immediately possible, in practice.
             (a) Comet names are generally announced on Minor Planet Electronic
               Circulars by the MPC at the time of publication of a first set of
               orbital elements.  The hope is to maintain stability by preventing
               previously observed comets (particularly lost comets) from getting
               new names.
             (b) Occasionally this is not possible, and when a lost comet has been
               given a new name(s) before it is shown to be the same comet, the
               new name(s) is (are) to be added to the original name(s).
        5.3  New comets later identified with observations of "asteroidal"
           objects (or previously unidentified cometary images) in previous
           months or years do not get names added due to such findings after
           the initial comet name is published.
        5.4  Prior to the publication of a name for a new comet, if the comet
           can be identified with an object reported as asteroidal at the same
           apparition on two or more nights by a single or team discoverer,
           so that a minor-planet designation has already been given, it can
           also have a name for that individual or team discoverer added,
           provided that there is only one other name for the comet (for a
           total of two names).
        5.5  Also in the stated interest of simplicity, comet names will not
           be changed by adding numerals after names (where multiple comets
           carry the same discoverers' names), as was done during much
           of the twentieth century, as this merely complicates matters.
           Officially, there is no need to retain numerals on short-period
           comets that have routinely carried them in the past, because the
           robust designation system obviates their necessity and because
           the historical facts belie any logic associated with using numerals
           (different numerals were used in different places, and there are
           gaps in the numerals used even recently).
     [Examples:  C/1955 N1 (Bakharev-Macfarlane-Krienke),
                 C/1980 O1 (Cernis-Petrauskas), C/1997 L1 (Zhu-Balam),
                 2P/Encke, 27P/Crommelin, 97P/Metcalf-Brewington,
    Guideline 6:  Regarding unnamed comets.
        6.1  The WGSBN and MPC reserve the right to delay naming, possibly
           indefinitely.  Reasons for such delay may include:
             (a) A comet is found months or years after observation and
                 is no longer observable.  Exceptions have been made in
                 connection with team names for sungrazing comets observed by
                 space-based coronagraphs.
             (b) A comet's orbit is not determinable due to poor observations
                 or short arc of observation; in such cases, an object will
                 usually be given an "X/" designation.
             (c) There is no agreement among team members for (an) observing
                 program(s) claiming the discovery.
     [Examples:  C/1931 AN, C/1996 R3, C/1997 K2,
                 P/1997 T3 (Lagerkvist-Carsenty), C/2001 HT_50 (LINEAR-NEAT)]