ICARUS 26,85-98 (1975)

The New Martian Nomenclature of the InternationalAstronomical Union

IG. de VAUCOULEURS, 2J. BLUNCK, 3M.DAVIES, 4A. DOLLFUS,51. K. KOVAL, 6G. P. KUIPERt, 7H. MASURSKY, 8S. l\HYAMOTO,

9V. I. MOROZ, IOCARL SAGAN, AND IIBRADFORD SMITH

1 Department of Ast·ronomy, University of Texas, Austin, Texas 78712; 2Hamburg,Federal Republic of Germany; 3RAN D Corporation, Santa Monica, California 90-106 ;40bservatoire de Par is , 1\1[ eudon, France; 5M ain Astronomical Observatory, [JkrainianAcademy of Sciences, Kiev, U.S.S.R.; 6 University of Arizona, Tucson, A'rizona 8.ji21;

'U.S. Geological Survey, Flagstaff, Arizona 86001; 8J{tcasan Observatory,Cniversity of Kyoto, Yamashina, Kyoto, Japan; "Lnstitute jor Cosmic Research,

Moscow, V.S.S.R.; lOCornell University, Ithaca, New York 14853;11University of Arizona, Tucson, Arizona 85721

Received December 30, 1974

A new nomenclature for Martian regions and topographic features uncoveredby Mariner 9, as officially adopted by the International Astronomical Union, isdescribed. About 180 craters, generally of diameters >100km, have been named,as well as 13 classes of topographic features designated catena, chasma, dorsum,fossa, labyrinthus, mensa, mons, patera, planit.ia, planum, tholus, vallis, andvastit.as. In addition seven craters and the Kepler Dorsum are named on Phobos,and two craters on Deirnos , Coordinates and maps of each named feature aredisplayed.

In August 1970, a Working Group onMartian Nomenclature was appointed byJ. S. Hall, then President of Commission 16(Physics of the Planets) ofthe InternationalAstronomical Union during its XIVthGeneral Assembly at Brighton, England.The task assigned to this group was todevelop concrete proposals implementingthe following recommendations of a pre-decessor committee under the Chairman-ship of the late G. P. Kuiper (Trans. IAU,XIVB, 1970, p. 129).

(1) Substantially define the provinceboundaries and, in the process, possiblyadd or delete a few provinces, as mayappear desirable; and circulate amongmembers a map showing coordinates andproposed boundaries.

(2) Apply the principles of topo-gra phic nomenclature to the regions ade-quately covered by the Mariner 1969 data,and by such 1971 data as may becomeavailable.

(3) Propose appropriate names fort Deceased.

Copyright © 1975 by Academic Press, Inc.All rights of reproduction in any form reserved.Printed in Great Britain

some prominent Martian topographic fea-tures (with reference to the lists of namesalready submitted by Commission 16members).

The initial membership of the newWorking Group included G. de Vaucou-leurs (Chairman), A. Dollfus, C. Sag~'m,B. Smith, S. Miyamoto (members), andNI. Davies (consultant). To broaden thecompetence and geographic representationof the Working Group, G. P. Kuiper, I. K.Koval, and V. 1. Moroz were eo-opted asmembers in 1971; H. Masursky of the U.S.Geological Survey (USGS) in Flagstaff andJ. Blunck of Hamburg were eo-opted asconsultants in 1972. We received alsovaluable advice and contributions fromD. Ya. Martynov of Sternberg Astro-nomical Institute, VV. H. Picketing of theJet Propulsion Laboratory (JPL), J. S.Hall of Lowell Observatory, D. H. Menzel

"of Harvard, D. VV. G. Arthur of USGS,B. Y. Levin of Schmidt Institute, Moscow,T. C. Duxbury of JPL, and S. Soter andJ. Veverka of Cornell.

85

86 G. DE VAUCOULEURS ET AL.

Between August 1970and July 1973,theWorking Group held seven formal meetingssupplemented by extensive correspondencewhich was also used to obtain votes whenrequired. Two final meetings were held inAugust 1973 during the XVth GeneralAssembly of the LA.U. in Sydney,Australia. All discussions and notes weresummarized in 10 circulars which weretransmitted to the President ofCommission16, G. H. Pettengill, as supporting docu-mentation for the recommendations pre-sented to the Commission.

The report of the Working Group and itsspecific recommendations were endorsedby the membership of the Commission andsubsequently accepted by formal vote ofthe General Assembly, thereby becomingthe official IAU Nomenclature for themajor surface albedo and topographicfeatures of Mars (Trans. IAU, XVB, 1973).This scheme is described in the followingsections.

1. Designation of p?·ovinces. Instead of

the original concept of "provinces" definedby classical albedo features which some-times proved unworkable in practicebecause of the variability of many of thesemarkings and the indefiniteness of theirboundaries, the surface of the planet wasdivided into 30 geometric areas shown inFig. 1. These "quadrangles" correspond tothe individual charts of the 1: 5 millionscale atlases of topographic and albedomaps which are being produced at the D.S.Geological Survey and at The Universityof Texas from the Mariner 9 data. Theequatorial areas between +300 and -300

latitude are covered by 16maps inMercatorprojection measuring 450 in longitude by30° in latitude. The intermediate latitudesbetween ±30° and : 65° are covered by 12maps in Lambert conformal projectioneach measuring 60° in longitude by 35° inlatitude; the polar regions between ±65°and ±900 are covered by two maps in polarstereographic projection. The coordinatesof the boundaries shown in Fig. 1 are

1800 1200 600 00 3000 2400 1800 300

Amozonis Thnr slsLunoe Oxia

ArabiaSydis Elysium

Palus Palus MajorAmenthes

AMA 8 THR 9 LUN 10 OXl 11 ARA 12 SYR 13 AME 14 ELY 15

1800 1350 90° 450 00 3150 2700 2250 1800 00

MargaritiferSinus

MAR 19

PhoenicisLacus

PHE 17

1200

Memnonia Coprates

COP 18600

MEM 16

1800

MareTyrthenum

TYR 22

2400

SabaeusSinus

SAB 20

lapygia Aeolis

AEO 23

180" -300lAP 21

300"

FIG. 1. Distribution and nomenclature of thirty designated regions or "quadrangles" comprisingthe Martian surface.

IAU MARTIAN NOME~CLATURE 87

precisely defined by the edges of theMariner 9 1:5 million charts (1973 edition)and are in close agreement with a new

'aerographic coordinate system proposedat the Sydney meeting in separate reso-lutions of Commissions 4 and 16 andadopted by the IAU General Assembly(Trans. lAD, XVB, 1973).

Each chart is also designated by thename of a prominent classical albedofeature within its confines and by a three-letter abbreviation (shown on Fig. 1)whichwill be used as a prefix to the craterdesignation scheme described in Section2 below.

2. Crater designations. Within each chartall craters larger than approximately20km are to be assigned a two-letterdesignation from Aa to Zz in which thefirst letter is in order of increasing longi-tude from East to West and the second inorder of increasing latitude from South toNorth as shown in Fig. 2.

A total of approximately 6000 cratershave been so designated and are markedon the charts of the atlas of topographicmaps prepared at the D.S. GeologicalSurvey, Astrogeology Branch, Flagstaff,Arizona. In a few heavily cratered areas,the capacity of the two-letter scheme isexceeded and a third letter was added toprovide a designation for all craters largerthan the 20km limit. It is recommendedthat Martian craters be identified by thechart prefix followed by the letter desig-nation (e.g., SYR Aa).

3. Named craters. In addition to theletter scheme, a selection of the largestcraters, generally larger than 100km indiameter, received names of prominent,deceased individuals having contributedeither to the scientific study ofMars, or thelore of the planet, or to basic discoveries ofsignificance to the exploration of Mars orthe interpretation of its phenomena. Afterextensive discussion about 180names wereselected:which are listed in Appendix I andshown on Fig. 3.1

4. Other topographic features. Thirteenclasses of topographic features have beendesignated. Of these, twelve are named fornearby classical albedo features taken fromthe Schiaparelli orAntoniadi maps. Usuallyfollowing the name is the class of feature,e.g., Olympus Mons. One class of features,the Sinuous channels, are treated different-ly and named after "MARS" in variouslargely non-Indo European languages.Names and locations are listed in Appen-dices Ha and lIb and shown on Fig. 4.Definitions and examples are as follows.

(a) Gatena. Crater Chain. A chain orline of craters. There are three named,e.g., Tithonia Catena.

1 Early in 1974, on a proposal of C. Sagan,members of the (defunct) Working Group votedunanimously (but without lAU authority) toadd two craters to this list in honour of G. P.Kuiper (157°,-57°) and W. Vishniac (276°-77°).We recommend this resolution to the successorlAU committee on Planetary Nomenclature.

N

w

z y .x..··

zyx

E

cAaO ~

.... c 8 A

SFIG. 2. Double letter crater designation scheme within each 1: 5000000 map quadrangle.

IAU MARTIAN NOMENCLATURE 91

(b) Chasma. Canyon. An elongated,steep-sided depression, e.g. CopratesChasma. Thirteen have been named.

(c) Dorsum (Dorsa). Ridge(s). Irregu-lar, elongate prominence. One has beennamed, Argyre Dorsum.

(d) Fossa (Fossae). Ditches. Long,narrow, shallow depression. They generallyoccur in groups and are straight or curved.Thirteen have been named, e.g., ClaritasFossae.

(e) Labyrinthus. Valley complex.Complex, intersecting valleys, of whichthere is only one example, Noctis Laby-rinthus.

(f) Mensa (Mensae). Mesas. Flattopped prominence with cliffiike edges.Three have been named, e.g., NilosyrtisMensae.

(g) lvlons (Montes). Mountains. Alarge topographic prominence or chain ofelevations. Ten such features are desig-nated, e.g., Ascraeus Mons.

(h) Patera. Irregular crater or acomplex one with scalloped edges. Ninehave been designated, e.g., Alba Patera.

(i) Planitia. Plain. Smooth, lowareas.Ten have been designated, e.g., HellasPlanitia.

(j) Planum. Plateau. Smooth ele-vated area. Seven have been named, e.g.,Solis Planum.

(k) Tholus. Hill. Isolated domical

small mountain or hill. Eleven have beennamed, e.g., Albor Tholus.

(1) Vallis (V alles). Valley. A sinuouschannel, many with tributaries. These arenamed "Mars" in many languages, e.g., AlQahira Vallis is derived from the Arabicword for Mars. Eleven have been named. 1

(m) Vastitas. Extensive plain. The vastnorthern circumpolar plain is namedVastitas Borealis.

5. Craters on satellites. Craters on Phobosare named, by a subcommittee chaired byC. Sagan, after those involved with thediscovery, dynamics, or properties of theMartian satellites who are not alreadycommemorated onMars.Craters onDeimosare named after authors of literary orartistic allusions to the Martian satellites.Only Western Hemisphere craters onPho bos are named. The ridge emanatingfrom Crater Stickney is named KeplerDorsum. Adopted names are listed inAppendix III and locations on Phobos areshown on Fig. 5, which is a slight correctionof a map first published by Veverka et al.(1974). The two named craters on Deimosare located in the photographic atlas ofVeverka et al. (1974).

1 In addition, and with apologies to lat.inists,Valles Marineris, a name suggested by W. H.Pickering, eommemorates the Mariner spaceprobes which revealed the Martian top-ography.

ApPENDIXI: LARGECRATERNAMESONMARS

Name ,\ ep Name ,\ ep Name A rp

Adarns, W. S. 1970 +310 Bianchini, F. 970 -640 Chamberlain,

Agassiz, J. L. R. 89 -70 Bjerknes, W. 189 -43 T. C. 1240 _660

Airy, G. B. 0 - .5 Boeddicker, O. 197 -15 Charlier, C. V. L. 169 -69

Antoniadi, Bond,G.P. 36 -33 Clark, A. 134 -56

E.M. 299 +22 Bouguer, P. 333 -19 Coblentz, VV.W. 91 -55

Arago, F. 330 +10 Brashear, J. A. 120 -.54 Colurnbus, c.a 166 -29

Arrhonius, S. 237 -40 Briault, P. 270 -10 Comas Sola, J. 158 -20

Burroughs, Copernicus, N. 169 -50

Bakhuysen, E. R. 243 -72 Crommelin, 10 + 5

5. G. (van de Burton, C. E. 156 -14 Cruls, L. 197 -43

Sande) 344 -23 Curie, P. 5 +29

Baldet, F. 295 +23 Campbell,Barabashov, N. 69 +47 W. W. and Daly, R. A. 22 -66

Barnard, E. E. 298 -61 J.W. 195 -.54 Dana, J. D. 32 -73

Becquerel, H. 8 +22 Cassini, J. D. 328 +24 Darwin, G. H.

Beer, W. 8 -15 Cerul'li, V. 338 +32 and Ch. 20 -57

a Mariner IV designations; see lAD Trans. XIIIB, 99, 1967.