Tholus

In planetary nomenclature, a tholus (pl. tholi) is a small domical mountain or hill.^[1][2] The word is from the Greek θόλος, tholos (pl. tholoi),^[3] which means a circular building with a conical or vaulted roof.^[4] The Romans transliterated the word into the Latin tholus, which means cupola or dome.^[5] In 1973, the International Astronomical Union (IAU) adopted tholus as one of a number of official descriptor terms for topographic features on Mars and other planets and satellites.^[6][7] One justification for using neutral Latin or Greek descriptors was that it allowed features to be named and described before their geology or geomorphology could be determined.^[8] For example, many tholi appear to be volcanic in origin, but the term does not imply a specific geologic origin.^[9] Currently (March 2015), the IAU recognizes 56 descriptor terms.^[1] (See Planetary nomenclature.) Tholi are present on Venus, Mars, asteroid 4 Vesta and on Jupiter's moon Io.

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  Map of the Tharsis quadrangle showing major features, several of which are tholi. Tharsis contains many volcanoes, including Olympus Mons, the tallest known volcano in the solar system.
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  2001 Mars Odyssey THEMIS mosaic of Ceraunius Tholus (lower volcano) and Uranius Tholus (upper volcano). Ceraunius Tholus is about as high as Earth's Mount Everest.
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  Western part of Jovis Tholus, as seen by THEMIS on Mars Odyssey spacecraft. Jovis Tholus is in the Tharsis quadrangle.

Examples of tholi

• Hecates Tholus
• Tharsis Tholus

References

1. "Descriptor Terms (Feature Types)". Gazetteer of Planetary Nomenclature. International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). Archived from the original on 2014-06-23. Retrieved 2013-06-24.
2. Hargitai H. (2014). "Tholus, Tholi". In H. Hargitai; Á. Kereszturi. Encyclopedia of Planetary Landforms. Springer New York. doi:10.1007/978-1-4614-9213-9_371-1. ISBN 978-1-4614-9213-9.
3. Liddell & Scott (1889). An Intermediate Greek-English Lexicon. New York: Harper & Brothers. p. 368.
4. "Tholus". Encyclopædia Britannica.
5. Simpson, D.P. (1968). Cassell's New Latin Dictionary; Funk & Wagnalls: New York, p. 604.
6. De Vaucouleurs G.; Davies M.; Dollfus A.; Koval I. K.; Masursky H.; Miyamoto S.; et al. (September 1975). "The new Martian nomenclature of the international Astronomical Union" (PDF). Icarus. 26 (1): 85–98. Bibcode:1975Icar...26...85D. doi:10.1016/0019-1035(75)90146-3. Archived from the original (PDF) on August 7, 2014.
7. Greeley, R. (1994) Planetary Landscapes, 2nd ed.; Chapman & Hall: New York, pp. 35-36.
8. Russell, J.F.; Snyder, C.W.; Kieffer, H.H. (1992). Origin and Use of Martian Nomenclature in Mars, H.H. Kieffer et al., Eds.; University of Arizona Press: Tucson, AZ, p. 1310.
9. Russell, J.F.; Snyder, C.W.; Kieffer, H.H. (1992). Origin and Use of Martian Nomenclature in Mars, H.H. Kieffer et al., Eds.; University of Arizona Press: Tucson, AZ, p. 1312.

External links

• Lists of named tholi: on Venus, on Mars, on Vesta, on Io