Classical albedo features on Mars explained

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.[1] [2] [3]

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:

List of albedo features

Not listed here are the "canals" also observed and named by Schiaparelli, for which see the article 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 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 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
Mare Amphitrites "Sea of Amphitrite", a Greek sea-goddess Amphitrites Patera
Lucus Angitiæ "Grove of Angitia", named after the snake goddess
Depressiones Aoniæ
Aonius Sinus "Bay of the Muses" Aonia Mons, Aonia Planum, Aonia Terra, Aonia Tholus
Aponi Fons
Aquæ Apollinares
Aquæ Calidæ "Hot spring"
Aquarii Depressio "Lowland of Aquarius"
Arabia Arabia Terra
Arachoti Fons
Aram Aram, Biblical land of the Aramaeans Aram Chaos
Arcadia 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 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
Aurea Cherso
Aureum Cornu Aureum Chaos
Auroræ Sinus "Bay of the Dawn" Aurorae Planum, Aurorae Chaos
Ausonia 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

B-E

NamePronunciationMeaningModern name(s)
Baltia Baltia, IAU recognized albedo feature
Bandusiæ Fons
Bathys Portus Bathys Planum, changed to Icaria Planum
Benacus Lacus "Lake Benacus" (Lago di Garda in northern Italy)
Biblis Fons Biblis Patera, Biblis Tholus
Bosporium Promontorium "Cape of the Bosphorus"
Bosporus/Bosphorus Gemmatus "Bejewelled Bosphorus" Bosporos Planum, Bosporus Regio, Bosporos Rupes
Brangæna
Capri "Isle of Capri" Capri Chasma, Capri Mensa
Casius Mt Casius in Egypt, famous in antiquity for the nearby coastal marshes in which whole armies were reputed to have drownedCasius quadrangle
Castalia Fons "Castalian Springs"
Cebrenia Land of Cebrenia near Troy Cebrenia quadrangle
Cecropia "Land of Cecrops"
Ceraunius Ceraunius Catena, Ceraunius Fossae
Chalce Chalce Montes
Charitum Promontorium "Cape of the Graces" Charitum Montes
Chironis Fretum "Strait of Chiron"
Mare Chronium Planum Chronium, Chronius Mons
Chryse One of a pair of legendary islands, Chryse and Argyre, located in the Indian Ocean and said to be made of gold and silver Chryse Chaos, Chryse Colles, Chryse Planitia
Chrysokeras
Cimmeria Insula "Cimmerian Island"
Mare Cimmerium "Cimmerian Sea", named after an ancient Thracian seafaring people Terra Cimmeria
Circaeum Promontorium "Cape of Circe"
Claritas Latin for "bright" Claritas Fossae, Claritas Rupes
Clepsydra Fons "Water-clock fountain", a well in the Athenian acropolis.
Coprates River Coprates, now called the Dez, in modern Iran Coprates Chasma
Coracis Portus "Haven of Corax"
Cyane Fons "Cyane fountain", a spring in Sicily from which the Cyane river sprang, named for a nymph. Cyane Catena, Cyane Fossae
Cydonia poetic name for Crete Cydonia, Cydonia Mensae, Cydonia Labyrinthus, Cydonia Colles
Cynia Lacus
Danaïdum Depressio "Lowland of the daughters of Danaüs"
Daphne From Daphne ("bay laurel"), a nymph pursued by Apollo.
Deucalionis Regio "Region of Deucalion"
Dia
Diacria Diacria quadrangle
Dioscuria "Land of the Dioscuri"
Eden From Eden, the biblical paradise Eden Patera
Edom
Edom Promontorium "Cape of Edom"
Electris The principal island of the "Electrides", islands said to produce amber. Electris Mons
Elysium From Elysium, the Greek land of dead heroes Elysium Planitia, Elysium Mons, Elysium Fossae, Elysium quadrangle
Eridania Eridania Mons, Eridania Planitia, Eridania quadrangle, Eridania Scopulus
Mare Erythræum "Red Sea" Erythraea Fossae

F-L

NamePronunciationMeaningModern name(s)
Famæ Depressio "Lowland of Fame"
Ferentinæ Lucus "Grove of Ferentina"
Lucus Feronia "Grove of Wild Beasts"
Flevo Lacus
Gallinaria Silva
Mare Hadriaticum "Adriatic Sea" Aka Hadriaticum Mare Hadriacus Mons, Hadriaca Patera
Hammonis Cornu "Horn of Ammon"
Hellas "Greece" Hellas Planitia, Hellas Montes, Hellas quadrangle
Heræum Promontorium "Cape of Hera"
Hercynia Silva
Herculis Columnæ "Pillars of Hercules"
Herculis Pons "Bridge of Hercules"
Hesperia"Land of the Setting Sun" Hesperia Dorsa, Hesperia Planum
Hesperidum Lacus "Lake of the Hesperides
Hibe
Hippocrene Fons "Fountain of Hippocrene", near Mount Helicon
Hipponitis Palus
Horarum Promontorium "Cape of the Hours" Horarum Mons
Hypelaus A fountain in Ephesus.
Hyperboreus Lacus Greek/Latin: Far Northern LakeHyperboreae Undae
Iapygia Iapygia quadrangle
Icaria Icaria Fossae, Icaria Planum
Mare Icarium
Ierne A name for Ireland
Isidis Regio "Region of Isis" Isidis Planitia
Ismenius Lacus The Ismenian Spring near Thebes where Cadmus slew the guardian dragon Ismenia Patera, Ismeniae Fossae Ismenius Cavus, Ismenius Lacus quadrangle
Jani Fretum "Strait of Janus" Iani Chaos
Juventæ Fons "Fountain of Youth" a.k.a. Fons Juventæ Juventae Chasma, Juventae Dorsa
Labeatis Lacus Lake of the Labeates, a people of Illyria
Lausonius Lacus
Lemuria From Lemuria, a fictional sunken land in the Pacific or Indian Ocean
Lerne
Libya "Libya" Libya Montes
Lucrinus Lacus The Lucrine Lake in Roman Italy
Lunæ Lacus "Lake of the Moon" a.k.a. Lacus Lunæ Lunae Palus quadrangle, Lunae Planum

M-N

NamePronunciationMeaningModern name(s)
Mæisia Silva
Mapharitis
Mareotis "Land about Mareota", in Lower Egypt. Mareotis Fossae
Margaritifer Sinus "Pearlbearing Bay" Margaritifer Terra, Margaritifer Sinus quadrangle
Lucus Maricæ "Grove of Maríca", a nymph of Latium. Lucus Planum
Memnonia "Land of Memnon" Memnonia Fossae, Memnonia quadrangle
Meroë Insula "Island of Meroe" Meroe Patera
Messeis Fons
Lacus Mœris Lake Moeris, a lake in the Egyptian Fayum
Mons Argenteus "Silver mountain" Dorsa Argentea, Argentea Planum
Neith Regio "Region of Neith"
Nepheles Depressio "Lowland of cloud"
Nereïdum Promontorium "Cape of the Nereids Nereidum Montes
Nerigos Name of a fictional country, supposedly in or near Scandinavia
Nessonis Lacus
Niliacus Lacus "Lake of the Nile" Colles Nili
Nilokeras "Horn of the Nile" Nilokeras Fossae, Nilokeras Mensae
Nitriæ
Nix Atlantica "Atlantic Snow"
Nix Olympica "Olympian Snow" Olympus Maculae, Olympus Mons, Olympus Patera, Olympus Rupes
Noachis "Land of Noah" Noachis quadrangle, Noachis Terra
Nodus Gordii "Gordian Knot" Gordii Dorsum
Noti Sinus "Bay of Notus"
Novissima Thyle "Newest Thule"
Nuba Lacus

O-S

NamePronunciationMeaningModern name(s)
Mare Oceanidum "Sea of the Oceanids"Oceanidum Fossa, Oceanidum Mons
Octantis Depressio "Lowland of Octans"Octantis Cavi, Octantis Mons
Œnotria Oenotria Plana, Oenotria Scopuli
Ogygis Regio "Region of Ogyges"Ogygis Rupes, Ogygis Undae
Ophir From Ophir, a biblical land of goldOphir Catenae, Ophir Cavi, Ophir Chasma, Ophir Planum
Ortygia Ortygia Colles
Oxia Palus Oxia Chaos, Oxia Colles, Oxia Palus quadrangle
Palicorum Lacus
Palinuri Fretum "Strait of Palinurus"
Palinuri Sinus "Bay of Palinurus"
Pallas Lacus "Lake of Pallas"
Panchaia From the name of an island supposed to be in South ArabiaPanchaia Rupes
Phaëthontis "Land of Phaethon or Phaethon (son of Eos)" Phaethontis quadrangle
Phlegra From a district in Macedonia. Phlegra Montes
Campi Phlegræi "Fields of Phlegra"Phlegra Montes
Phœnicis Lacus "Lake of the Phoenix" a.k.a. Lacus Phœnicis Phoenicis Lacus quadrangle
Phrixi Regio "Region of Phrixus"Phrixi Rupes
Piscis Depressio "Depression of the Fish"
Depressio Pontica "Lowland of Pontus"
Promethei Sinus "Bay of Prometheus" Promethei Terra
Propontis From an old name for the Sea of Marmara
Protei Regio "Region of Proteus"
Pyrrhæ Regio "Region of Pyrrha"Pyrrhae Chaos, Pyrrhae Fossae
Rupes Tenuis Latin: "Thin Cliff"Tenuis Mensae, Rupes Tenuis
Sinus Sabæus "Bay of Sheba" Aka Sabaeus Sinus Terra Sabaea, Sinus Sabaeus quadrangle
Scandia From a name for Skåne or ScandinaviaScandia Cavi, Scandia Colles, Scandia Tholi
Scheria Insula "Scheria Island"
Semiramidis Lacus "Lake of Semiramis"
Serapium
Simoëntis Sinus "Bay of Simois"Simois Colles
Sirbonis Palus The army-swallowing Serbonian Bog near Mt Casius in Egypt
Mare Sirenum "Sea of Sirens" Terra Sirenum
Socratis Promontorium "Cape of Socrates"
Solis Fons "Fountain of the Sun"Obsolete
Solis Lacus "Lake of the Sun" Solis Planum
Stygis "Styx River", Greece Stygis Catena, Stygis Fossae
Syrtis Major Syrtis Major Planum, Syrtis Major quadrangle
Syrtis Minor now Gulf of Gabès in Tunisia. a.k.a. Syrtis Parva

T-Z

NamePronunciationMeaningModern name(s)
Tempe Vale of Tempe, Greece Tempe Fossae, Tempe Terra
Tharsis Tharsis Montes, Tharsis quadrangle
Thaumasia "Land of Wonders" Thaumasia Planum, Thaumasia quadrangle
Thyle I "First Thule" Thyles Montes, Thyles Rupes
Thyle II "Second Thule"
Thyles Collis "Hill of Thule"
Thyles Mons "Mountain of Thule"
Thymiamata "Incenses"
Tiphys Fretum
Titanum Sinus "Bay of the Titans"
Tithonius Lacus Tithoniae Catenae, Tithoniae Fossae, Tithonium Chasma
Trinythios
Trivii Fons "Fountain of the Crossroads" (east of Trivium Charontis)
Trivium Charontis "Crossroads of Charon"
Mare Tyrrhenum "Tyrrhenian Sea" Mare Tyrrhenum quadrangle, Tyrrhenus Mons, Tyrrhena Terra
Uchronia "Nowhen"
Ulyxis Fretum "Strait of Ulysses" Ulyxis Rupes
Utopia "Nowhere, Utopia" Utopia Planitia
Vulcani Pelagus "Sea of Vulcan"
Xanthi Sinus "Bay of Xanthus" Xanthe Dorsa, Xanthe Terra
Xisuthri Regio "Region of Xisuthrus"
Yaonis Regio "Region of Emperor Yao"
Zephyria "Land of the West Wind (Zephyr)" Zephyria Planum, Zephyria Mensae

See also

Further reading

External links

Notes and References

  1. Web site: History of Planetary Nomenclature . planetarynames.wr.usgs.gov . International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN) . 3 Dec 2016.
  2. Web site: Martian Feature Name Nomenclature . www.marsartgallery.com . 3 Dec 2016.
  3. United States Geological Survey Astrogeology Program, "Mars Nomenclature: Albedo Feature", Gazetteer of Planetary Nomenclature.