{ "id": "epq2n44s0f", "slug": "aspledon-undae", "title": "Aspledon Undae", "updated": "2026-10-25", "topic_path": [ { "id": "places", "label": "Places and geography", "api_url": "https://www.edgepedia.org/api/v1/topics/places" }, { "id": "places.extraterrestrial", "label": "Extraterrestrial places", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial" }, { "id": "places.extraterrestrial.surface-features", "label": "Planetary surfaces and named features", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial.surface-features" }, { "id": "places.extraterrestrial.surface-features.martian-features", "label": "Martian surface features", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial.surface-features.martian-features" }, { "id": "places.extraterrestrial.surface-features.martian-regions", "label": "Martian regions and terrain", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial.surface-features.martian-regions" }, { "id": "places.extraterrestrial.surface-features.martian-plains-highlands", "label": "Martian plains, terrae, and polar regions", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial.surface-features.martian-plains-highlands" }, { "id": "places.extraterrestrial.surface-features.martian-plains-highlands.northern-planitiae", "label": "Northern lowlands planitiae", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial.surface-features.martian-plains-highlands.northern-planitiae" } ], "geo": [ { "id": "geo.nongeo.nodate.places.extraterrestrial.surface-features.martian-plains-highlands", "label": "Non-geographic · Not dated: Martian plains, terrae, and polar regions", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial.surface-features.martian-plains-highlands", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.nodate", "label": "Non-geographic · Not dated", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate" }, { "id": "geo.nongeo.nodate.places", "label": "Places and geography", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places" }, { "id": "geo.nongeo.nodate.places.extraterrestrial", "label": "Extraterrestrial places", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial" }, { "id": "geo.nongeo.nodate.places.extraterrestrial.surface-features", "label": "Planetary surfaces and named features", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial.surface-features" }, { "id": "geo.nongeo.nodate.places.extraterrestrial.surface-features.martian-features", "label": "Martian surface features", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial.surface-features.martian-features" }, { "id": "geo.nongeo.nodate.places.extraterrestrial.surface-features.martian-regions", "label": "Martian regions and terrain", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial.surface-features.martian-regions" }, { "id": "geo.nongeo.nodate.places.extraterrestrial.surface-features.martian-plains-highlands", "label": "Martian plains, terrae, and polar regions", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial.surface-features.martian-plains-highlands" } ] } ], "excerpt": "Aspledon Undae is a 215.20 km dune field (unda) on Mars in Vastitas Borealis near the north polar cap, centered at 73.06°N, 309.65°E; IAU-approved March 20, 2007, named after the classical albedo feature Aspledon, a Boeotian city and son of Poseidon.", "snippet": "Aspledon Undae is a 215.20 km dune field (unda) on Mars in Vastitas Borealis near the north polar cap, centered at 73.06°N, 309.65°E; IAU-approved March 20, 2007, named after the classical albedo feature Aspledon, a Boeotian city and son of Poseidon.", "node": "places.extraterrestrial.surface-features.martian-plains-highlands.northern-planitiae", "markdown": "# Aspledon Undae\n\n**Aspledon Undae** is a dune field on Mars, in the northern lowland plains of [Vastitas Borealis](https://www.edgepedia.org/vastitas-borealis) near the planet's north polar ice cap. It is one of six dune fields on Mars formally classified as an unda (plural undae) by the International Astronomical Union, with a diameter of 215.20 km and its center at 73.06° north latitude, 309.65° east longitude.[1](https://planetarynames.wr.usgs.gov/Feature/14279) • [2](https://planetarynames.wr.usgs.gov/SearchResults?Feature+Type=45_Unda&Target=20_Mars)\n\n| Key fact | Detail |\n|---|---|\n| Feature type | Unda, undae, the IAU descriptor term for a dune field[1](https://planetarynames.wr.usgs.gov/Feature/14279) |\n| Size | Diameter 215.20 km; center latitude 73.06°, center longitude 309.65° E (planetocentric, +East)[1](https://planetarynames.wr.usgs.gov/Feature/14279) |\n| Approval | Adopted by the IAU on March 20, 2007; origin given as a classical albedo feature name, ethnicity Greek[1](https://planetarynames.wr.usgs.gov/Feature/14279) |\n| Setting | Vastitas Borealis, near the north polar ice cap; mapped in quadrangle MC-1 (Mare Boreum)[3](https://science.nasa.gov/photojournal/aspledon-undae-false-color/) • [1](https://planetarynames.wr.usgs.gov/Feature/14279) |\n| Name origin | Aspledon, in Greek myth a son of Poseidon and the nymph Mideia, and a Boeotian city mentioned in Homer's Catalogue of Ships[4](https://www.researchgate.net/publication/401387531_Encyclopedia_of_Martian_Geography_Volume_1) |\n| Neighboring feature | Aspledon Crater, 18 km across, lies near the dune field[4](https://www.researchgate.net/publication/401387531_Encyclopedia_of_Martian_Geography_Volume_1) |\n| Imaging | Part of the dune field and a sand-sheet-filled crater were photographed in false color by the THEMIS camera on Mars Odyssey (image PIA24605, added April 23, 2021)[3](https://science.nasa.gov/photojournal/aspledon-undae-false-color/) |\n\n## Naming\n\nThe name follows the IAU convention for Martian dune fields, which are named after the nearest named albedo feature on the classical Schiaparelli or Antoniadi maps.[5](https://wenamethestars.inkleby.com/feature/14279) The parent feature here is the classical albedo feature Aspledon, recorded earlier as Aspledon Lacus at about 64° north, 297° (Lowell 1901; Antoniadi 1929; IAU 1958).[4](https://www.researchgate.net/publication/401387531_Encyclopedia_of_Martian_Geography_Volume_1) In Greek mythology and ancient geography, Aspledon was a son of [Poseidon](https://www.edgepedia.org/poseidon) and the nymph Mideia, and also a city of Boeotia near modern Pirgos, mentioned by [Homer](https://www.edgepedia.org/homer) in the Catalogue of Ships of the *Iliad*; a related tradition makes Aspledon a lake in Boeotia, formed by the floods of the river Cephissus south of Orchomenos.[4](https://www.researchgate.net/publication/401387531_Encyclopedia_of_Martian_Geography_Volume_1)\n\nThe descriptor term unda comes from the Latin for water waves and is used to mean undulatory in planetary nomenclature; all dune fields outside Earth are called unda or undae.[6](https://themis.asu.edu/zoom-20180314a)\n\n## Location and setting\n\nThe Gazetteer of Planetary Nomenclature places the feature between 71.47° and 75.14° north latitude and 305.83° to 315.04° east longitude in the planetocentric, east-positive coordinate system, equivalent to about 44.96° to 54.17° west longitude; it falls in the MC-1 (Mare Boreum) quadrangle.[1](https://planetarynames.wr.usgs.gov/Feature/14279) NASA describes the dune field as lying in Vastitas Borealis, near the north polar ice cap.[3](https://science.nasa.gov/photojournal/aspledon-undae-false-color/)\n\n## Relation to the north polar dune fields\n\nAspledon Undae is one of six named undae on Mars. Five of them ring the north polar cap: [Abalos Undae](https://www.edgepedia.org/abalos-undae) (442.74 km across), [Hyperboreae Undae](https://www.edgepedia.org/hyperboreae-undae) (463.65 km), [Olympia Undae](https://www.edgepedia.org/olympia-undae) (1507.96 km, the largest continuous dune field on Mars), Siton Undae (222.97 km), and Aspledon Undae itself; Ogygis Undae (87.70 km) lies in the southern hemisphere.[2](https://planetarynames.wr.usgs.gov/SearchResults?Feature+Type=45_Unda&Target=20_Mars) • [6](https://themis.asu.edu/zoom-20180314a) Aspledon Undae and Siton Undae were both approved on the same date, March 20, 2007, while Abalos and Hyperboreae Undae date from 1988 and Olympia Undae from 2003.[2](https://planetarynames.wr.usgs.gov/SearchResults?Feature+Type=45_Unda&Target=20_Mars)\n\n## Observation\n\nThe region has been mapped by NASA's Mars Odyssey orbiter through its Thermal Emission Imaging System (THEMIS). A false-color THEMIS VIS image released on April 23, 2021 shows part of the dune field together with a crater filled by a large sand sheet; the image was captured on May 8, 2019 at latitude 71.2167, longitude 309.213. False-color combinations of the camera's five filters can reveal subtle surface variations not visible in a single band.[3](https://science.nasa.gov/photojournal/aspledon-undae-false-color/)\n\n## References\n\n1. [Aspledon Undae, Gazetteer of Planetary Nomenclature, USGS Astrogeology Science Center](https://planetarynames.wr.usgs.gov/Feature/14279)\n2. [Nomenclature Search Results, Feature Type Unda, Target Mars, Gazetteer of Planetary Nomenclature](https://planetarynames.wr.usgs.gov/SearchResults?Feature+Type=45_Unda&Target=20_Mars)\n3. [Aspledon Undae – False Color, NASA Science Photojournal](https://science.nasa.gov/photojournal/aspledon-undae-false-color/)\n4. [Encyclopedia of Martian Geography, Volume 1](https://www.researchgate.net/publication/401387531_Encyclopedia_of_Martian_Geography_Volume_1)\n5. [Aspledon Undae (Mars), We Name The Stars (Inkleby)](https://wenamethestars.inkleby.com/feature/14279)\n6. [Investigating Mars: Olympia Undae, Mars Odyssey Mission THEMIS, Arizona State University](https://themis.asu.edu/zoom-20180314a)\n\n---\n*Topic: Encyclopedia › Places and geography › Extraterrestrial places › Planetary surfaces and named features › Martian surface features › Martian regions and terrain › Martian plains, terrae, and polar regions › Northern lowlands planitiae*\n\n*Initially written Oct 21, 2026 · Edited: Oct 25, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/aspledon-undae", "markdown_url": "https://www.edgepedia.org/aspledon-undae.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Aspledon Undae\", Edgepedia (EdgeChat), https://www.edgepedia.org/aspledon-undae. Edgepedia Community License 1.0.", "credit_md": "\"[Aspledon Undae](https://www.edgepedia.org/aspledon-undae)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/aspledon-undae](https://www.edgepedia.org/aspledon-undae). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Aspledon Undae\", Edgepedia (EdgeChat), https://www.edgepedia.org/aspledon-undae. Edgepedia Community License 1.0.", "speakable": "Aspledon Undae is a 215.20 km dune field on Mars in Vastitas Borealis near the north polar cap, centered at 73.06°N, 309.65°E; IAU-approved March 20, 2007, named after the classical albedo feature Aspledon, a Boeotian city and son of Poseidon." }