Occator (crater)

Further information: Bright spots on Ceres § Spot 5

Occator
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Occator imaged by Dawn from LAMO. Fractures are associated with the bright spots and some other areas.
Feature typeImpact crater
LocationCeres
Coordinates19°52′N 238°51′E / 19.86°N 238.85°E / 19.86; 238.85[1]
Diameter92 kilometres (57 mi)
Depth3 km
DiscovererDawn
NamingAfter Occātor, a helper God of Ceres

Occator /ɒˈkeɪtər/ is an impact crater located on Ceres, the largest object in the main asteroid belt that lies between the orbits of Mars and Jupiter, that contains "Spot 5", the brightest of the bright spots observed by the Dawn spacecraft. It was known as "Region A" in ground-based images taken by the W. M. Keck Observatory on Mauna Kea.[2]

The crater was named after Occator, the Roman god of the harrow and a helper to Ceres. The name Occator was officially approved by the IAU on 3 July 2015.[1]

On 9 December 2015, scientists reported that the bright spots on Ceres, including those in Occator, may be related to a type of salt, particularly a form of brine containing magnesium sulfate hexahydrite (MgSO4·6H2O); the spots were also found to be associated with ammonia-rich clays.[3] More recently, on 29 June 2016, scientists reported the bright spot to be mostly sodium carbonate (Na
2CO
3), implying that hydrothermal activity was probably involved in creating the bright spots.[4][5] In August 2020, NASA confirmed that Ceres was a water-rich body with a deep reservoir of brine that percolated to the surface in various locations causing the "bright spots", including those in Occator crater.[6][7] The percolation of brine from a deep internal reservoir to the surface at Occator crater was first modeled in 2019.[8]

A small dome in the center of the crater is 3 km across and about 340 meters height. It is named Cerealia Tholus[9] and is covered by bright salt deposits named Cerealia Facula.[10] The group of thinner salt deposits to the east are named Vinalia Faculae [sic].[11] In July 2018, NASA released a comparison of physical features, including Occator, found on Ceres with similar ones present on Earth.[12]

  1. ^ a b "Occator (crater)". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program., accessed 6 July 2015
  2. ^ Kupper; et al. (22 January 2014). "PIA17831: Water Detection on Ceres". NASA. Retrieved 30 July 2015.
  3. ^ Landau, Elizabeth (9 December 2015). "New Clues to Ceres' Bright Spots and Origins". NASA. Retrieved 10 December 2015.
  4. ^ Landau, Elizabeth; Greicius, Tony (29 June 2016). "Recent Hydrothermal Activity May Explain Ceres' Brightest Area". NASA. Retrieved 30 June 2016.
  5. ^ De Sanctis, Maria Christina; et al. (29 June 2016). "Bright carbonate deposits as evidence of aqueous alteration on (1) Ceres". Nature. 536 (7614): 54–57. Bibcode:2016Natur.536...54D. doi:10.1038/nature18290. PMID 27362221. S2CID 4465999.
  6. ^ McCartney, Gretchen; Hautaluoma, Grey; Johnson, Alana (10 August 2020). "Mystery Solved: Bright Areas on Ceres Come From Salty Water Below". NASA. Retrieved 12 August 2020.
  7. ^ McCartney, Gretchen (11 August 2020). "Mystery solved: Bright areas on Ceres come from salty water below". Phys.org. Retrieved 12 August 2020.
  8. ^ Quick, Lynnae C.; et al. (1 March 2019). "A Possible Brine Reservoir Beneath Occator Crater: Thermal and Compositional Evolution and Formation of the Cerealia Dome and Vinalia Faculae". Icarus. 320: 119–135. Bibcode:2019Icar..320..119Q. doi:10.1016/j.icarus.2018.07.016. S2CID 125508484.
  9. ^ "Cerealia Tholus". planetarynames.wr.usgs.gov.
  10. ^ "Cerealia Facula". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
  11. ^ "Vinalia Faculae". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
  12. ^ Landau, Elizabeth; McCartney, Gretchen (24 July 2018). "What Looks Like Ceres on Earth?". NASA. Retrieved 25 July 2018.