1% Status info: 2% A. Wolf 2017 3% 20171029 AW: A first version of text 4% 20171210 GZ: small changes for finalization. 5 6\chapter{Planetary nomenclature} 7\label{ch:Nomenclature} 8 9Planetary nomenclature\newFeature{0.17.0}, like terrestrial nomenclature, 10is a system of uniquely identifying features on the surface of a planet or 11natural satellite so that the features can be easily located, described, and discussed. 12Since the invention of the telescope, astronomers have given names to the surface 13features they have discerned, especially on the Moon and Mars. To standardize planetary 14nomenclature, the International Astronomical Union (IAU)\index{IAU} was assigned in 1919 the task 15of selecting official names for features on solar system bodies\footnote{History of 16Planetary Nomenclature -- \url{https://planetarynames.wr.usgs.gov/Page/History}}. 17 18\begin{figure}[ht] 19\centering\includegraphics[width=\textwidth]{stellarium-nomenclature.jpg} 20\caption{Feature nomenclature of the Moon.} 21\label{fig:Nomenclature:Moon} 22\end{figure} 23 24Since version 0.17.0 Stellarium supports planetary nomenclature, which allows using the 25planetarium for educational and informative purposes on the one hand, and as tool for 26recognition and targeting of the planetary features for advanced amateurs on the other 27hand, avoiding the need for additional cartographic software in the field. 28 29All planetary nomenclature items are stored in a dedicated internal format, 30and all names are translatable to provide better understanding of those names 31by average users and newbies -- for example in schools or universities. 32Of course all nomenclature items are available for finding in the Search Tool 33after enabling the display of nomenclature (this feature is rather costly in terms of 34computing power and therefore is by default disabled in the GUI). 35 36\emph{The information in sections \ref{sec:Nomenclature:ApprovingNames}--\ref{sec:Nomenclature:DescriptorTerms}, 37included here for reference, has been taken from the ``Gazetteer of Planetary Nomenclature'' website 38by the International Astronomical Union (IAU)\index{IAU} Working Group for Planetary System Nomenclature 39(WGPSN)}\footnote{\url{https://planetarynames.wr.usgs.gov}, visited on 2017-10-30}. 40 41\section{Format of nomenclature data file} 42\label{sec:Nomenclature:format} 43 44File \file{data/nomenclature.fab} is a plain text file in UTF-8 encoding and has a very simple data format: 45\begin{itemize} 46\item One item per line; 47\item Each item contains seven elements with white space (``space'' or ``tab'' character) as delimiter. 48\end{itemize} 49File \file{data/nomenclature.dat} is a zipped \file{data/nomenclature.fab} file and used to minimize time of loading the data and reduce size of the installation package. 50 51\begin{center} 52\begin{tabularx}{\textwidth}{l|l|X}\toprule 53\emph{Item} & \emph{Type} & \emph{Comment}\\\midrule 54planet name & string & English name of the planet, moon or minor body carrying the named feature\\%\midrule 55ID of planetary feature & integer & unique integer, equal to Feature ID obtained from Gazetteer of Planetary Nomenclature\\%\midrule 56translatable name of planetary feature & string & English name, containing context data for translators\\%\midrule 57type of planetary feature & string & 2-char code (see \emph{designation} column in table in section \ref{sec:Nomenclature:DescriptorTerms})\\%\midrule 58center latitude of planetary feature & float & decimal degrees\\%\midrule 59center longitude of planetary feature & float & decimal degrees\\%\midrule 60size of planetary feature & float & kilometers\\\bottomrule 61\end{tabularx} 62\end{center} 63 64\noindent Example: 65\begin{configfile} 66Vesta 15201 _("Caesonia","crater") AA 31.20117 249.93457 104.23 67\end{configfile} 68 69\section{How names are approved by the IAU} 70\label{sec:Nomenclature:ApprovingNames}\index{IAU} 71When images are first obtained of the surface of a planet or satellite, a theme for naming features is chosen 72and a few important features are named, usually by members of the appropriate IAU task group (a commonly 73accepted planet-naming group). Later, as higher resolution images and maps become available, additional 74features are named at the request of investigators mapping or describing specific surfaces, features, 75or geologic formations. Anyone may suggest that a specific name be considered by a task group. 76If the members of the task group agree that the name is appropriate, it can be retained for use 77when there is a request from a member of the scientific community that a specific feature be named. 78Names successfully reviewed by a task group are submitted to the IAU Working Group for Planetary System 79Nomenclature (WGPSN)\footnote{Working Group for Planetary System Nomenclature -- \url{https://planetarynames.wr.usgs.gov/}}. 80Upon successful review by the members of the WGPSN, names are considered provisionally approved and can be 81used on maps and in publications as long as the provisional status is clearly stated. 82Provisional names are then presented for adoption to the IAU's General Assembly, which met triennially in the past, 83and which now adopts nomenclature for planetary surface features as required. A name is not considered to be 84official -- that is, ``adopted'' -- until the General Assembly has given its approval. 85 86\section{IAU rules and conventions} 87\label{sec:Nomenclature:RulesAndConventions}\index{IAU} 88Names adopted by the IAU must follow various rules and conventions established and amended through the years by the Union. These include: 89\begin{enumerate} 90\item Nomenclature is a tool and the first consideration should be to make it simple, clear, and unambiguous. 91\item In general, official names will not be given to features whose longest dimensions are less than 100 meters, 92 although exceptions may be made for smaller features having exceptional scientific interest. 93\item The number of names chosen for each body should be kept to a minimum. Features should be 94 named only when they have special scientific interest, and when the naming of such features is useful 95 to the scientific and cartographic communities at large. 96\item Duplication of the same surface feature name on two or more bodies, and of the same name for satellites 97 and minor planets, is discouraged. Duplications may be allowed when names are especially appropriate and 98 the chances for confusion are very small. 99\item Individual names chosen for each body should be expressed in the language of origin. 100 Transliteration for various alphabets should be given, but there will be no translation from one language to another. 101\item Where possible, the themes established in early solar system nomenclature should be used and expanded on. 102\item Solar system nomenclature should be international in its choice of names. 103 Recommendations submitted to the IAU national committees will be considered, but final selection of the names 104 is the responsibility of the International Astronomical Union. 105 Where appropriate, the WGPSN strongly supports an equitable selection of names from ethnic groups, 106 countries, and gender on each map; however, a higher percentage of names from the country planning a 107 landing is allowed on landing site maps. 108\item No names having political, military or religious significance may be used, except for names of political figures prior to the 19th century. 109\item Commemoration of persons on planetary bodies should not normally be a goal in itself, 110 but may be employed in special circumstances and is reserved for persons of high and enduring international standing. 111 Persons being so honored must have been deceased for at least three years, before a proposal may be submitted. 112\item When more than one spelling of a name is extant, the spelling preferred by the person, or used in an authoritative reference, should be used. 113 Diacritical marks are a necessary part of a name and will be used. 114\item Ring and ring-gap nomenclature and names for newly discovered satellites are developed in joint deliberation 115 between WGPSN and IAU Commission X2. Names will not be assigned to satellites until their orbital elements are 116 reasonably well known or definite features have been identified on them. 117\item Accessible and authoritative sources, including Internet sources, are required for adopted names. 118 Wikipedia is not sufficient as a source, but may be useful for identifying appropriate sources. 119\end{enumerate} 120 121\noindent In addition to these general rules, each task group develops additional conventions as it formulates an interesting 122and meaningful nomenclature for individual planetary bodies. Most of these conventions are self evident from study of the appendixes that follow. 123 124\section{Naming conventions} 125\label{sec:Nomenclature:NamingConventions}\index{IAU} 126Names for all planetary features include a descriptor term, with a few exceptions. For craters, the descriptor term is implicit. 127Some features named on Io and Triton do not carry a descriptor term because they are ephemeral. 128 129In general, the naming convention for a feature type remains the same regardless of its size. 130Exceptions to this rule are channels (valles) on Mars and Venus, and craters on the Moon, Mars, and Venus; 131naming conventions for these features differ according to size. 132The categories for naming features on each planet or satellite (and the exceptions) are listed in 133Categories for Naming Features on Planets and Satellites\footnote{% 134 Surface Feature Categories -- \url{https://planetarynames.wr.usgs.gov/Page/Categories}}. 135One feature classification, regio, was originally used on early maps of the Moon and Mercury (drawn from telescopic observations) 136to describe vague albedo features. It is now also used to delineate a broad geographic region. 137 138Named features on bodies so small that coordinates have not yet been determined are identified on drawings or images 139of the body that are included in the IAU Transactions volume of the year when the names were adopted. 140Satellite rings and gaps in the rings are named for scientists who have studied these features; 141drawings that show these names are also included in the pertinent Transactions volume. 142Names for atmospheric features are informal at present; a formal system will be chosen in the future. 143 144The boundaries of many large features (such as terrae, regiones, planitiae, and plana) are not topographically or geomorphically distinct; 145the coordinates of these features are identified from an arbitrarily chosen center point. 146Boundaries (and thus coordinates) may be determined more accurately from geochemical and geophysical data obtained by future missions. 147 148During active missions, small surface features are often given informal names. 149These may include landing sites, spacecraft impact sites, and small topographic features, such as craters, hills, and rocks. 150Such names will not be given official status by the IAU, except as provided for by Rule 2 above. 151As for the larger objects, official names for any such small features would have to conform to established IAU rules and categories. 152 153When a satellite has been discovered through the efforts of a large scientific team, 154the list of individual team members may be too long to include all contributors. 155In such cases, credit for the discovery will go to the science team. 156 157\newpage 158\section{Descriptor terms (feature types)} 159\label{sec:Nomenclature:DescriptorTerms} 160Descriptor terms are intended to represent morphological characteristics, not geological origin. 161The WGPSN does not endorse any specific scientific hypotheses when assigning descriptors. 162 163\begin{longtable}{l|c|p{72mm}}\toprule 164\emph{Feature} & \emph{Designation} & \emph{Description}\\\midrule 165Albedo Feature & AL & Geographic area distinguished by amount of reflected light\\%\midrule 166Arcus, arcūs & AR & Arc-shaped feature\\%\midrule 167Astrum, astra & AS & Radial-patterned features on Venus \\\midrule 168Catena, catenae & CA & Chain of craters \\%\midrule 169Cavus, cavi & CB & Hollows, irregular steep-sided depressions usually in arrays or clusters\\%\midrule 170Chaos, chaoses & CH & Distinctive area of broken terrain\\%\midrule 171Chasma, chasmata & CM & A deep, elongated, steep-sided depression\\%\midrule 172Collis, colles & CO & Small hills or knobs\\%\midrule 173Corona, coronae & CR & Ovoid-shaped feature\\%\midrule 174Crater, craters & AA & A circular depression\\\midrule 175Dorsum, dorsa & DO & Ridge\\\midrule 176Eruptive center & ER & Active volcanic centers on Io\\\midrule 177Facula, faculae & FA & Bright spot\\%\midrule 178Farrum, farra & FR & Pancake-like structure, or a row of such structures\\%\midrule 179Flexus, flexūs & FE & A very low curvilinear ridge with a scalloped pattern\\%\midrule 180Fluctus, fluctūs & FL & Flow terrain\\%\midrule 181Flumen, flumina & FM & Channel on Titan that might carry liquid\\%\midrule 182Fossa, fossae & FO & Long, narrow depression\\%\midrule 183Fretum, freta & FT & Strait, a narrow passage of liquid connecting two larger areas of liquid\\\midrule 184Insula, insulae & IN & Island (islands), an isolated land area (or group of such areas) surrounded by, 185 or nearly surrounded by, a liquid area (sea or lake)\\\midrule 186Labes, labēs & LA & Landslide\\%\midrule 187Labyrinthus, labyrinthi & LB & Complex of intersecting valleys or ridges\\%\midrule 188Lacuna, lacunae & LU & Irregularly shaped depression on Titan having the appearance of a dry lake bed\\%\midrule 189Lacus, lacūs & LC & ``Lake'' or small plain; on Titan, a ``lake'' or small, 190 dark plain with discrete, sharp boundaries\\%\midrule 191Landing site name & LF & Lunar features at or near Apollo landing sites\\%\midrule 192Large ringed feature & LG & Cryptic ringed features\\%\midrule 193Lenticula, lenticulae & LE & Small dark spots on Europa\\%\midrule 194Linea, lineae & LI & A dark or bright elongate marking, may be curved or straight\\%\midrule 195Lingula, lingulae & LN & Extension of plateau having rounded lobate or tongue-like boundaries\\\midrule 196Macula, maculae & MA & Dark spot, may be irregular\\%\midrule 197Mare, maria & ME & ``Sea''; on the Moon, low albedo, relatively smooth plain, generally of large extent; 198 on Mars, dark albedo areas of no known geological significance; 199 on Titan, large expanses of dark materials thought to be liquid hydrocarbons\\%\midrule 200Mensa, mensae & MN & A flat-topped prominence with cliff-like edges\\%\midrule 201Mons, montes & MO & Mountain\\\midrule 202Oceanus, oceani & OC & A very large dark area on the moon\\\midrule 203Palus, paludes & PA & ``Swamp''; small plain\\%\midrule 204Patera, paterae & PE & An irregular crater, or a complex one with scalloped edges\\%\midrule 205Planitia, planitiae & PL & Low plain\\%\midrule 206Planum, plana & PM & Plateau or high plain\\%\midrule 207Plume, plumes & PU & Cryo-volcanic features on Triton\\%\midrule 208Promontorium, promontoria & PR & ``Cape''; headland promontoria\\\midrule 209Regio, regiones & RE & A large area marked by reflectivity or color distinctions from adjacent areas, 210 or a broad geographic region\\%\midrule 211Reticulum, reticula & RT & Reticular (netlike) pattern on Venus\\%\midrule 212Rima, rimae & RI & Fissure\\%\midrule 213Rupes, rupēs & RU & Scarp\\\midrule 214Satellite Feature & SF & A feature that shares the name of an associated feature. 215 For example, on the Moon the craters referred to as ``Lettered Craters'' 216 are classified in the gazetteer as ``Satellite Features''\\%\midrule 217Saxum, saxa & SA & Boulder or rock\\%\midrule 218Scopulus, scopuli & SC & Lobate or irregular scarp\\%\midrule 219Serpens, serpentes & SE & Sinuous feature with segments of positive and negative relief along its length\\%\midrule 220Sinus, sinūs & SI & ``Bay''; small plain; on Titan, bays within seas or lakes of liquid hydrocarbons\\%\midrule 221Sulcus, sulci & SU & Subparallel furrows and ridges\\\midrule 222Terra, terrae & TA & Extensive land mass\\%\midrule 223Tessera, tesserae & TE & Tile-like, polygonal terrain\\%\midrule 224Tholus, tholi & TH & Small domical mountain or hill\\\midrule 225Unda, undae & UN & Dunes\\\midrule 226Vallis, valles & VA & Valley\\%\midrule 227Vastitas, vastitates & VS & Extensive plain\\%\midrule 228Virga, virgae & VI & A streak or stripe of color\\\bottomrule 229\end{longtable} 230 231 232\section*{Author and Acknowledgement} 233\label{sec:Nomenclature:Acknowledgments} 234The nomenclature feature has been implemented by Teresa Huertas Roldán supported by the ``ESA Summer of Code in Space 2017'' programme. 235 236%%% Local Variables: 237%%% mode: latex 238%%% TeX-master: "guide" 239%%% End: 240 241