CARUS 29, 155-157 (1976)

Topographic Nomenclature on Planetary Bodies

PETER lVI. MILLlVIAN

Notional Research Council of Canada,Ottawa, Canada

Received February 27, 1976; revised March 6, 1976

General guidlines are presented for International Astronomical Union decisions onnomenclature for surface features on the planets and their satellites.

This note is written to inform planetaryscientists of the system set up by the Inter-national Astronomical Union (IAU) in 1973 todeal with the current requirements for nomen-clature on the surfaces of the planets and theirsatellites, and to survey the types of problems wehave had to contend with. As President of thelA U Working Group for Planetary SystemNomenclature (vVGPSN), I am not personallycommitted to anyone viewpoint, but I am veryanxious to see action taken to provide a usefulnomenclature that is internationally approvedand that satisfies the majority of those who haveneed to refer to planetary detail.

Before the days of interplanetary spacecraftthe problems of extraterrestrial topographicnomenclature were confined primarily to thelarge amount of detail charted on the near sideof the Moon and to the albedo features on Marsthat had been identified with Earth-based tele-scopes. Prior to 1973 a Working Group for Lunar>~crnenclature reported to the lA U through',. '!:'.mission 17, and a Working Group onMal'tian Nomenclature operated within Commis-sion 16. These groups, among other activities,established successfully over 500 new names forfeatures on the far side of the Moon (Menzelet al., 1971),and named some 180large craters onMars, Phobos, and Deimos, as photographed byMal'iner spacecraft (de Vaucouleurs et al., 1975).

By the time of the Sydney IAU General Assem-bly in 197:3 it had become evident that topo-gTaphic nomenclature would be required withinrhe next few decades-for a considerable numberof planetary bodies in the solar system. It isobvious that the nomenclature established forthe various planets and satellites should becoordinated in some way. It is also desirable tohave early decisions on the nornericlat.ure of anewly investigated body, and this may requireCopyright IQ 1976 by Academic Press, Inc. 155A 11fights of reproduction in any form reserved.Pr in ted in Great Britain

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rapid action. For example, various governmentagencies in the United States are now involved inthe production of new map series for the Moon,Mars, and Mercury, and it is necessary to providenomenclature data on a fairly short time scale sothat printing schedules can be met.

To provide a more comprehensive system fordealing with planetary nomenclature, the lAU inSydney established five nomenclature TaskGroups, with responsibility for developing therequired nomenclature for the surface featuresof the Moon, Mercury, Venus, Mars, and theouter solar system. These five Task Groupsreport, through their chairmen, to the v\TGPSN,which in turn reports directly to the ExecutiveCommittee of the IAU (Pettengill, 19i4). Suchan organization enables action on nomenclatureto be taken in between General Assemblies,leaving only the formal ratification to beeffected at the next following General Assemblyof the IAU.

The following terms are convenient forindicating the four levels of action with thesequence outlined above:

Recommendations that have passed a TaskGroup are proposed names which can then becertified by the Working Group and, when passedby the Executive Committee become prouisionainames. Formal approval is given by the GeneralAssembly and the names are then ap prooed byIAU.

The Task Groups and the Working Groupdeal with all extraterrestrial topographic nomen-clature on the solid surfaces of bodies in the solarsystem and also, when needed, with the namingof unnamed natural satellites. They are notconcerned with the naming of asteroids, comets,and meteor streams, as well-established systemsof nomenclature already exist in these cases.

Members of nomenclature groups today must

156 PETER IV1.l\lILLi\IAN

work with a muG.!lbroader philosophy than theyworked with in the past. Before the end of the20th century up to 40 planetary bodies in thesolar system alone may require topographicnomenclature. Disciplines other than astronomyare now directly involved-for example, geology,geophysics, and engineering. to mention onlythree of the more obv ious. The United Xationshas an active body, the "Group of Experts onGeographical Names," which coordinates andapproves, on an international basis, the namesfor terrest.rial topographic features. This Groupof Exp srts has set up a Working Group on theNames of Extraterrestrial Topographic Features.The IAU/WGPS,N has established lines ofcommunication with this UN 'Working Groupand with the UN Group of Experts. In this waywe can assess the reaction of the nonscientistto nomenclature policy over a broad inter,national spectrum, since the United ).rationsincludes almost three times the number ofnat.ions represented in the IAU. United Nat.ions'delegates from countries that do not adhere tothe IAU can assist us greatly by providing forfuture use lists of suitable names for planetarybodies.

It is evident that people often become erno-tionally involved in nomenclature decisions.With a large number of individuals from variousdisciplines actively engaged in this field, it isclear that no one person can hope to see all hissuggestions adopted, Compromise will inevitablybe necessary in most cases. It is easy to findthose who are ready to criticize what has alreadybeen done; it is much more difficult to find thosewho are prepared to devote many man-hoursto working objectively on the solution of anomenclature problem.

At its first meeting, held in Ottawa, Ontario,on June 27-28, 1974, the IAU/vYGPS).[ listedthe following seven basic principles for planetarysystem nomenclature, and these were laterapproved by the Executive Committee of theIAU.

1. Nomenc!ature is a tool and the firstconsideration shall be to make it simple, clear.and unambigious.

2. The number of names chosen for each bodyshould be kept to a minimum, and governed bythe anticipated requirements of the scientificcommunity.

3. Although there will be exceptions. dupli-cation of the same name on two or more bodiesshould be avoided.

4. In general, individual names chosen shouldbe single words, and expressed in the language oforigin. Transliteration and pronunciation forvarious alphabets should be given, but there

will be no translation from one language toanother.

5. Where possible, consideration should alsobe given to the traditional aspects of anynomenclature system, provided that this doesnot cause confusion.

6. Solar system nomenclature shall be inter,national in its choice of names. Recommenda-tions submitted by IAu National Committeeswill be considered. Final approval of allYselection is the responsibility of the InternationalAstronomical Union

i. "Ye must look to the future in general dis-cussions of solar system nomenclature andattempt to lay the groundwork for futurerequirements that will result from the develop-ment of the space program.

One of the oft, recurring discussions in the fieldof nomenclature is whet.her to use letters andnumbers for reference to a given feature or toassign a name. For accurate reference to a specificpoint we can always use an established eo-ordinate system such as latitute and longitude.But where a feature is, or may be. frequentlyreferred to, the majority opinion seems to favora distinctive name. On Earth we travel on landfrom place to place by name rather than bynumber. During "'orld War n, I served 6 yearsin the Royal Canadian Air Force as navigator,navigation instructor, and operational researchofficer. We lived with maps, day and night, ancloften our lives depended on them. Maps neededon a mission were selected by sheet name, eventhough they all were numbered as well, Mypractical experience would indicate that it iswise to have a dist.inctive name for each sheetin a given map series. For large-scale map series,however, it is not always necessary to assignsheet names until there is some prospect of thesheets in question being printed.

In special cases it may be advisable to have adouble system of names for the sheets in a small,scale series, This has already happened in thecases of Mars and Mercury where the albedofeatures mapped from Earth-based observationshave retained their classical names, while thelargely independent craters and scarps photo-graphed from Mar-inerspacecraft are given namesfrom a different category.

Another area of discussion is whether to namefeatures after people, living things. inanimateobjects, or even abstract nouns. Up to now therehas been a preference for naming distinctivesurface markings. such as craters. on theterrestrial planets and the Moon after men andwomen of note. Except for a very few specialexceptions the individuals commemorated mustbe deceased. It has also been agreed to prohibit

the assignment of the names of individuals"kno\vn primarily as religious leaders, 01' asrni lit.ary leaders, political leaders, and philo-sophers, of the 19th and 20th centuries."

For very-largescale maps of unique andspecific areas, such as landing sites on the Moonor Mars, names can be chosen without restrictingtheir possible use on other map sheets. Examplesof name banks of this type. already chosen on aninternational basis, are the first names of menand women for use on the }lIoon, and the namesof small terrestrial villages for use on Mars.

It may be objected that, in choosing names, thepopular emphasis of today will be reflected inthe nomenclature selected for-any given planetor satellite. This is very true and is unavoidable.However, strict adherence to Basic PrincipleNo. 2 will leave plenty of room for futureadditions; and it is quite appropriate to have aflavor of the early decades of the space ageretained in our planetary nomenclature.

There has been a desire, particulariy among thenonscientists in the United Nations' groups, tolayout a very detailed plan of nomenclatureat the present time for the entire solar system.Since, for example, we do not know in advancethe types of surface features that may bediscovered on the satellites of Jupiter andSaturn, it would be unwise to formulate detailedrules too hastily. The IAUjWGPSN will attemptto foresee the future needs for nomenclatureas the program of interplanetary flights develops.Banks of names will be prepared in advance sothat suitable nomenclature of a general basicsystem may be given to the cartographerswit hout delay. We have already suggested auniform set of descriptive Latin terms for typesof topographic features. For any given planetarybody, selections may be made from this set,tu use with the assigned nomenclature. NewLa till terms can be added as required.

In conclusion, I wish to emphasize that it isimportant for our nomenclature groups to receivesuggestions and opinions from a wide rangeof individuals and nations. In particular weshould like to hear the views of those who willbe using planetary nomenclature m theirscientific publications.

ApPENDIX

Working Group for Planetary System Nomen-clature. P. :'vI.Millrnan, Ottawa, Ontario, Canada(President); B. .Iu. Levin, Moscow, U.S.S.R.;C. H. lVIa:yer, Washington, n.c., U.S.A.;D. D. Morrison. Honolulu, Hawaii, U.S.A.;T. C. Owen, Stony Brook. N.Y., U.S.A.; G. H.

Pettengill, Cambridge, Massachusetts, D.S.A.;S. K. Runcorn, Newcastle-upon-Tyne, U.K.;B. A. Smith, Tucson, Arizona, U.S.A.

Task Group for Lunar Nomenclature. P. M.Millman, Ottawa, Ontario, Canada (ActingChairman); A. Dollfns, Paris, France; F. EI-Baz,Wash irigt.on , D.C., D.S.A.; K. P. F'lorenskij ,Moscow, U.S.S.R.: H. Masursky , Flagstaff,Arizona, U.S.A.; D. H. Menzel, Cambridge,Massachusetts. U.S.A.; S. K' Runcorn, New-castle-upon-Tyne, -C.K.; V. V. Shevcheriko,Moscow, D.S.S.H.

T'aslc Group for JIereury Xomen dature. D. D.Morrison , Honolulu. Ha.wa.ii, U.S.A. (Chairman);M. E. Davies, Santa Monica, California, U.S.A.;A. Dollfus, Paris, France; O. J. Gingerich.Cambridge, Massachusetts, D.S.A.; R. IVI.Goldstein, Pasadena, California, D.S.A.; J. E.Guest, London, U.K.; Yn. N. Lipskij, Moscow,D.S.S.R.; B. A. Smith, Tucson, Arizona, U.S.A.

Task Group for renus Nomenclature. G. H.Pettengill, Cambridge, Massachusetts, U.S.A.(Chairman); R. M. Golclstein, Pasadena, Cali-fornia, U.S.A.; M. Ya.Marov, Moscow, U.S.S.R.;H. Masurs'ky, Flagstaff, Arizona, U.S.A.

Task Grourp for J1ars Nomenclature. B. A.Smith, Tueson, Arizona, U.S.A. (Chairman);A. Dollfus, Paris, France; IVI.Ya. Marov, Moscow,U.S.S.R.; H. Masursky, Flagstaff, Arizona,U.S.A.; S. Miyamot.o, Kyoto, Japan; A. V.Morozhenko, Kiev, Ukraine, U.S.S.R.; C. Sagan,It.haca, New York, "C.S.A.

Task G7'O'Upfor Outer Solar System Nomen-clature. T. C. Owen. Stony Brook, N.Y., U.S.A.(Chairman); K. Aksnes, Cambridge, Massa-chusetts, D.S.A.; ::VI. S. Bobrov , Moscow,U.S.S.R.; M. E. Davies, Santa Monica, Cali-fornia. U.S.A.; D. Gantier, Paris, France;B. A. Smith, Tueson, Arizona, U.S.A.; V. G.Tejfel'. Alma-Ata, Kazakh S.S.H., U.S.S.H.

REFERE~CES

DE VAL"COGLEvRS,G., BLL"NCK,J., D.-\VIES,M.,DOLLFUS, A., KOYAL, 1. K., K1JIPER, G. P ..lVL-\sGRSKY,H., MIYAlVIOTO,S., MOROZ,V. 1..SAG_-\N,C., AND S:.1ITH, B. (1975). The newMartian nomenclature of the InternationalAstronomical Union. Lcarus 26, 85-98.

MENZEL, D. H., :'IImNAERT, lVI., LEVIN, B.,DOLLFvS, A., ANDBELL. B. (1971). Report onlunar nomenclature by the Wor-king Group ofCommission 17 of the 1.A.U. Space Sei. Rev.12, 136-186

PETTENGILL, G. H. (1974). Commission 16:Physical study of planets and satellites.T'rans, Int. Astroll. ['nion B 15, 105-108.