ICARUS 26,85-98 (1975) The New Martian Nomenclature of the International Astronomical 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; 3 RAN D Corporation, Santa Monica, California 90-106 ; 40bservatoire de Par is , 1\1[ eudon, France; 5M ain Astronomical Observatory, [J krainian Academy 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; 11 University of Arizona, Tucson, Arizona 85721 Received December 30, 1974 A new nomenclature for Martian regions and topographic features uncovered by Mariner 9, as officially adopted by the International Astronomical Union, is described. 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, and vastit.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 are displayed. In August 1970, a Working Group on some prominent Martian topographic fea- Martian Nomenclature was appointed by tures (with reference to the lists of names J. S. Hall, then President of Commission 16 already submitted by Commission 16 (Physics of the Planets) ofthe International members). Astronomical Union during its XIVth The initial membership of the new General Assembly at Brighton, England. Working Group included G. de Vaucou- The task assigned to this group was to leurs (Chairman), A. Dollfus, C. Sag~'m, develop concrete proposals implementing B. Smith, S. Miyamoto (members), and the following recommendations of a pre- NI. Davies (consultant). To broaden the decessor committee under the Chairman- competence and geographic representation ship of the late G. P. Kuiper (Trans. IAU, of the Working Group, G. P. Kuiper, I. K. XIVB, 1970, p. 129). Koval, and V. 1. Moroz were eo-opted as (1) Substantially define the province members in 1971; H. Masursky of the U.S. boundaries and, in the process, possibly Geological Survey (USGS) in Flagstaff and add or delete a few provinces, as may J. Blunck of Hamburg were eo-opted as appear desirable; and circulate among consultants in 1972. We received also members a map showing coordinates and valuable advice and contributions from proposed boundaries. D. Ya. Martynov of Sternberg Astro- (2) Apply the principles of topo- nomical Institute, VV. H. Picketing of the gra phic nomenclature to the regions ade- Jet Propulsion Laboratory (JPL), J. S. Hall of Lowell Observatory, D. H. Menzel quately covered by the Mariner 1969 data, " and by such 1971 data as may become of Harvard, D. VV. G. Arthur of USGS, available. B. Y. Levin of Schmidt Institute, Moscow, (3) Propose appropriate names for T. C. Duxbury of JPL, and S. Soter and t Deceased. J. Veverka of Cornell. Copyright © 1975 by Academic Press, Inc. 85 All rights of reproduction in any form reserved. Printed in Great Britain 86 G. DE VAUCOULEURS ET AL. Between August 1970and July 1973,the the original concept of "provinces" defined Working Group held seven formal meetings by classical albedo features which some- supplemented by extensive correspondence times proved unworkable in practice which was also used to obtain votes when because of the variability of many of these required. Two final meetings were held in markings and the indefiniteness of their August 1973 during the XVth General boundaries, the surface of the planet was Assembly of the LA.U. in Sydney, divided into 30 geometric areas shown in Australia. All discussions and notes were Fig. 1. These "quadrangles" correspond to summarized in 10 circulars which were the individual charts of the 1: 5 million transmitted to the President of Commission scale atlases of topographic and albedo 16, G. H. Pettengill, as supporting docu- maps which are being produced at the D.S. mentation for the recommendations pre- Geological Survey and at The University of Texas from the Mariner 9 data. The sented to the Commission. 0 0 The report of the Working Group and its equatorial areas between +30 and -30 latitude are covered by 16maps in Mercator specific recommendations were endorsed 0 by the membership of the Commission and projection measuring 45 in longitude by subsequently accepted by formal vote of 30° in latitude. The intermediate latitudes the General Assembly, thereby becoming between ±30° and : 65° are covered by 12 the official IAU Nomenclature for the maps in Lambert conformal projection major surface albedo and topographic each measuring 60° in longitude by 35° in features of Mars (Trans. IAU, XVB, 1973). latitude; the polar regions between ±65° This scheme is described in the following and ±900 are covered by two maps in polar stereographic projection. The coordinates sections. 1. Designation of p?·ovinces. Instead of of the boundaries shown in Fig. 1 are 0 0 0 0 0 240 180 30 0 0 0 300 1800 120 60 Lunoe Oxia Sydis Arabia Amenthes Elysium Amozonis Thnr sls Palus Palus Major ELY 15 11 ARA 12 SYR 13 AME 14 LUN 10 OXl 0 AMA 8 THR 9 0 0 0 0 180 0 0 0 270 225 0 0 315 1800 135 90° 45 Mare Phoenicis Margaritifer Sabaeus lapygia Aeolis Memnonia Coprates Tyrthenum Lacus Sinus Sinus AEO 23 MAR 19 SAB 20 lAP 21 TYR 22 MEM 16 PHE 17 COP 18 0 2400 180" -30 0 300" 1800 1200 60 FIG. 1. Distribution and nomenclature of thirty designated regions or "quadrangles" comprising the Martian surface. 87 IAU MARTIAN NOME~CLATURE precisely defined by the edges of the 3. Named craters. In addition to the Mariner 9 1:5 million charts (1973 edition) letter scheme, a selection of the largest and are in close agreement with a new craters, generally larger than 100km in 'aerographic coordinate system proposed diameter, received names of prominent, at the Sydney meeting in separate reso- deceased individuals having contributed either to the scientific study of Mars, or the lutions of Commissions 4 and 16 and adopted by the IAU General Assembly lore of the planet, or to basic discoveries of significance to the exploration of Mars or (Trans. lAD, XVB, 1973). Each chart is also designated by the the interpretation of its phenomena. After name of a prominent classical albedo extensive discussion about 180names were selected:which are listed in Appendix I and feature within its confines and by a three- 1 letter abbreviation (shown on Fig. 1)which shown on Fig. 3. will be used as a prefix to the crater 4. Other topographic features. Thirteen designation scheme described in Section classes of topographic features have been designated. Of these, twelve are named for 2 below. 2. Crater designations. Within each chart nearby classical albedo features taken from all craters larger than approximately the Schiaparelli or Antoniadi maps. Usually 20km are to be assigned a two-letter following the name is the class of feature, designation from Aa to Zz in which the e.g., Olympus Mons. One class of features, first letter is in order of increasing longi- the Sinuous channels, are treated different- tude from East to West and the second in ly and named after "MARS" in various order of increasing latitude from South to largely non-Indo European languages. Names and locations are listed in Appen- North as shown in Fig. 2. A total of approximately 6000 craters dices Ha and lIb and shown on Fig. 4. have been so designated and are marked Definitions and examples are as follows. on the charts of the atlas of topographic (a) Gatena. Crater Chain. A chain or maps prepared at the D.S. Geological line of craters. There are three named, Survey, Astrogeology Branch, Flagstaff, e.g., Tithonia Catena. Arizona. In a few heavily cratered areas, the capacity of the two-letter scheme is 1 Early in 1974, on a proposal of C. Sagan, exceeded and a third letter was added to members of the (defunct) Working Group voted provide a designation for all craters larger unanimously (but without lAU authority) to than the 20km limit. It is recommended add two craters to this list in honour of G. P. that Martian craters be identified by the Kuiper (157°,-57°) and W. Vishniac (276°-77°). chart prefix followed by the letter desig- We recommend this resolution to the successor lAU committee on Planetary Nomenclature. nation (e.g., SYR Aa). N z y x w E c AaO ~ z y .x..·· .... c 8 A S FIG. 2. Double letter crater designation scheme within each 1: 5000000 map quadrangle. IAU MARTIAN NOMENCLATURE 91 (b) Chasma. Canyon. An elongated, small mountain or hill. Eleven have been steep-sided depression, e.g. Coprates named, e.g., Albor Tholus. Chasma. Thirteen have been named. (1) Vallis (V alles). Valley. A sinuous (c) Dorsum (Dorsa). Ridge(s). Irregu- channel, many with tributaries. These are lar, elongate prominence. One has been named "Mars" in many languages, e.g., Al Qahira Vallis is derived from the Arabic named, Argyre Dorsum. 1 (d) Fossa (Fossae). Ditches. Long, word for Mars. Eleven have been named. narrow, shallow depression. They generally (m) Vastitas. Extensive plain. The vast occur in groups and are straight or curved. northern circumpolar plain is named Thirteen have been named, e.g., Claritas Vastitas Borealis. 5. Craters on satellites.