The classical albedo features of Mars are the light and dark features that can be seen on the planet Mars through an Earth-based telescope. Before the age of space probes, several astronomers created maps of Mars on which they gave names to the features they could see. The most popular system of nomenclature was devised by Giovanni Schiaparelli, who used names from classical antiquity. Today, the improved understanding of Mars enabled by space probes has rendered many of the classical names obsolete for the purposes of cartography; however, some of the old names are still used to describe geographical features on the planet.
History Observing albedo features
Early telescopic astronomers, observing Mars from a great distance through primitive instruments (though they were advanced for their day), were limited to studying albedo contrasts on the surface of the planet. These lighter and darker patches rarely correspond to topographic features and in many cases obscure them. The origins of the albedo contrasts were a mystery. The lighter patches at the poles were correctly believed to be a frozen substance, either water or carbon dioxide, but the nature of the dark patches seen against the general reddish tint of Mars was uncertain for centuries. When Giovanni Schiaparelli began observing Mars in 1877, he believed that the darker features were seas, lakes, and swamps and named them accordingly in Latin (mare, lacus, palus etc.). Within a few decades, however, most astronomers came to agree that Mars lacks large bodies of surface water. The dark features were then thought by some to be indications of Martian vegetation, since they changed shape and intensity over the course of the Martian year. They are now known to be areas where the wind has swept away the paler dust, exposing a darker surface, often basaltic rock; so their borders change in response to windstorms on the Martian surface that move the dust around, widening or narrowing the features.
The dust-storms themselves also appear as light patches, can cover vast areas and sometimes last for many weeks; when Mariner 9 arrived in Martian orbit in November 1971 the entire planet was covered by a single enormous dust-storm, with only the peaks of the four or five highest mountains showing above it. This variability may explain many of the differences between telescopic observations over the years.
Early non-classical names
The first map of Martian albedo features was published in 1840 by Johann Heinrich Mädler and Wilhelm Beer, but they simply labelled the features a, b, c ... without giving them names. Over the next two decades the most prominent features picked up various informal names (such as the Hourglass Sea for what is now Syrtis Major Planum) but there was no overall system.
The first astronomer to name Martian albedo features systematically was Richard A. Proctor, who in 1867 created a map (based in part on the observations of William Rutter Dawes) in which several features were given the names of astronomers who had been involved in mapping Mars. In some cases, the same names were used for multiple features. Proctor's names remained in use for several decades, notably in several early maps drawn by Camille Flammarion in 1876 and Nathaniel Green in 1877.
Schiaparelli's classical names
However, within a few decades Proctor's names were superseded by a new scheme devised by Giovanni Schiaparelli, whose observations differed from Proctor's, and who used this difference to justify drawing up an entirely new system of nomenclature. Schiaparelli was an expert on ancient astronomy and geography, and used Latin names, drawn from the myths, history and geography of classical antiquity; dark features were named after ancient seas and rivers, light areas after islands and legendary lands.
When E. M. Antoniadi took over as the leading telescopic observer of Mars in the early 20th century, he followed Schiaparelli's names rather than Proctor's, and the Proctorian names quickly became obsolete. In his encyclopedic work La Planète Mars (1930) Antoniadi used all Schiaparelli's names and added more of his own from the same classical sources. However, there was still no 'official' system of names for Martian features.
In 1958, the International Astronomical Union set up an ad hoc committee under Audouin Dollfus, which settled on a list of 128 officially recognised albedo features. Of these, 105 came from Schiaparelli, 2 from Flammarion, 2 from Percival Lowell, and 16 from Antoniadi, with an additional 3 from the committee itself. This involved a considerable amount of pruning; Antoniadi's La Planète Mars had mentioned 558 named features.United States Geological Survey Astrogeology Program, "Mars Nomenclature: Albedo Feature", Gazetteer of Planetary Nomenclature.
The pictures returned by interplanetary spacecraft, notably the observations made from Martian orbit by Mariner 9 over the course of 1972, have revolutionized the scientific understanding of Mars, and some of the classical albedo features have become obsolete as they do not correspond clearly with the detailed images provided by the spacecraft. However, many of the names used for topographic features on Mars are still based on the classical nomenclature for the feature's location; for instance, the albedo feature 'Ascraeus Lacus' provides the basis of the name of the volcano Ascraeus Mons in roughly the same position.
In addition, since most Earth-based amateur telescopes are not powerful enough to resolve the topographic surface features of Mars, amateur astronomers still use many of the old feature-names to orient themselves and record their observations.
Common feature names
Several Latin words involved here are common nouns. These are generally, but not always, second in the name, but are usually ignored in alphabetizing below:
Campi () – fields Cherso () – peninsula Cornu () – horn, peninsula Depressio () – lowland Fastigium () – summit Fons () – fountain Fretum () – strait Insula () – island Lacus () – lake Lucus () – grove Mare () – sea Nix () – snow Palus () – marsh Pons () – bridge Promontorium () – cape Regio () – region Silva () – wood Sinus () – bay
List of albedo features Not listed here are the "canals" also observed and named by Schiaparelli, for which see the articles Martian canals and List of Martian canals.
Note that the pronunciation refers to English pronunciation, not Latin or Italian.
A
NamePronunciationMeaningModern name(s) Abalos A no-longer existent island in the North Sea, east of Heligoland Abalos Colles, Abalos Mensa, Abalos Scopuli, Abalos Undae Achæorum Portus "Harbor of the Achaeans" Acherusia Palus "Marsh of Acherusia", named after the legendary swamps in Greek mythology Achillis Pons "Bridge of Achilles" Mare Acidalium "Sea of Acidalia", named for the fountain Acidalia where the Graces bathed Acidalia Colles, Acidalia Mensa, Acidalia Planitia Æolis a modification of Aeolia, the name of the floating western island of Aiolos, the ruler of the winds Aeolis Mensae, Aeolis Planum Aëria From a poetic name for Egypt Aeria, IAU recognized albedo feature Ætheria – the land of the living, as referred to in Virgil's Aeneid Aetheria, IAU recognized albedo feature Æthiopis Land of the Ethiopians Aethiopis, IAU recognized albedo feature Aganippe Fons "Aganippe's Fountain", legendary home of a Greek naiad Aganippe Fossa Alcyonia Land of kingfishers. Amazonis "Land of the Amazon", legendary warrior women Amazonis Mensa, Amazonis Planitia, Amazonis Sulci Amenthes Alternate name for Duat, the Egyptian land of the dead Amenthes Cavi, Amenthes Fossae, Amenthes Planum, Amenthes Rupes Ammonium Ancient name for the Siwa Oasis Mare Amphitrites "Sea of Amphitrite", a Greek sea-goddess Amphitrites Patera Lucus Angitiæ "Grove of Angitia", named after the snake goddess Depressiones Aoniæ "Lowlands of the Muses", who came from Helicon in Aonia Aonius Sinus "Bay of the Muses" Aonia Mons, Aonia Planum, Aonia Terra, Aonia Tholus Aponi Fons Roman name for the Bagni d'Abano, warm-water baths near Padua Aquæ Apollinares "Apollo's Waters"; Roman name for the Bagni di Stigliano baths in Canale Monterano, Tuscany Aquæ Calidæ "Hot spring" Aquarii Depressio "Lowland of Aquarius" Arabia Arabian Peninsula Arabia Terra Arachoti Fons "Fountain of Arachotus", a river in Afghanistan Aram Aram, Biblical land of the Aramaeans Aram Chaos Arcadia From Arcadia, a region of the central Peloponnesus Arcadia Chaos, Arcadia Dorsa, Arcadia Planitia Arduenna Latin names for the Ardennes forests Arethusa Fons "Arethusa's Fountain", after the Greek nymph Argyre I One of a pair of legendary islands, Chryse and Argyre, located in the Indian Ocean and said to be made of gold and silver Argyre Cavi, Argyre Planitia, Argyre Rupes, Argyre quadrangle Argyre II "Second Silver Land" (see above) Argyroporos "Silver Strait" Ariadnes Depressio "Lowland of Ariadne", a Greek heroine Ariadnes Colles Aromatum Promontorium "Cape of Fragrant Spices" Aromatum Chaos Arsia Silva Arsia Silva, forest northwest of Rome where the Tarquinii were defeated Arsia Chasmata, Arsia Mons, Arsia Sulci Arsinoës Depressio Lowland of Arsinoë, the name of various Greek and Egyptian figures Arsinoes Chaos Artynia Fons "Artynia's Fountain", referring to Lake Artynia in Asia Minor Artynia Catena Aryn Promontorium "Cape of Aryn" Fastigium Aryn "Summit of Aryn" Ascræus Lacus "Ascraeus Lake", a poetic paraphrase of "heliconian" or "rural" Ascraeus Chasmata, Ascraeus Mons, Ascraeus Sulci Astræ Lacus "Lake of the Astra", Greek star-gods Atalantes Depressio Lowland of Atalanta, Greek heroine Nix Atlantica "Snows of Atlas", a Titan in Greek mythology Atlantidum Sinus "Bay of the Atlantises" (just south of Atlantis I and II, see below) Atlantis I "First Atlantis", mythical drowned land Atlantis Chaos Atlantis II "Second Atlantis" (see above) Atlantis Chaos Augila Awjila, a city in Cyrenaica Aurea Cherso "Golden Peninsula", ancient name for the Malay Peninsula Aureum Cornu "Golden Horn", inlet dividing Constantinople Aureum Chaos Auroræ Sinus "Bay of the Dawn" Aurorae Planum, Aurorae Chaos Ausonia From a poetic name for Italy Ausonia Cavus, Ausonia Mensa, Ausonia Montes Mare Australe "Southern Sea" Chasma Australe, Australe Lingula, Australe Mensa, Australe Montes, Planum Australe, Australe Scopuli, Australe Sulci, Mare Australe quadrangle
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