Hanami Planum

Hanami Planum

Feature type	Planum; highland region
Location	Ceres
Coordinates	15°00′N130°00′W / 15.00°N 130.00°W / 15.00; -130.00 [1]
Diameter	555 km [2] : 741
Peak	6 km [2] : 741
Discoverer	Dawn
Eponym	Hanami

Hanami Planum, formerly named Erntedank Planum, is a highland region on the dwarf planet and giant asteroid Ceres.

Observation and naming

On 5 March 2015, NASA's Dawn spacecraft entered orbit around Ceres, observing and mapping its surface features in detail for the first time. ^[3] The plateau was originally given the name Erntedank Planum by the International Astronomical Union (IAU) on 4 December 2015, after the German thanksgiving festival of Erntedankfest . ^[4] However, the name was dropped on 20 June 2016 and replaced with Hanami Planum. The new name comes from Hanami , the Japanese custom of viewing cherry blossoms. ^[1]

Geography and geology

Hanami Planum is a highland area centered near 15°N, 130°W, primarily placing it inside the Occator quadrangle. Spanning about 555 kilometres (345 mi) and rising as high as 6 kilometres (3.7 mi), it is the only discrete topographic high on Ceres ^{[5] : 130  [2] : 741} It is the third largest geological feature on Ceres, after Vendimia Planitia and Samhain Catenae; ^[6] the latter broadly coincides with Hanami Planum. ^{[7] : 11} Several major named craters occupy the highland, including Nepen, Azacca, Lociyo, and the bright Occator. ^{[5] : 130  [6]} Other major craters border Hanami Planum, such as Kirnis to the east and Ezinu to the northwest. ^{[5] : 130  [8] : 3195}

Hanami Planum is associated with a broad, distinct negative isostatic gravity anomaly, ^{[2] : 741} meaning that local gravity is weaker than normal. ^[9] The negative gravity anomalies suggest that Hanami Planum lies in a region of low-density material, with a mass deficit of 97.1+1.6
−1.5×10¹⁶ kg, ~0.1% the mass of Ceres. The region includes the most extreme negative anomaly observed on Ceres, with a strength of < –95 mGal southeast of Occator at 12°N, 113°W. This anomaly is associated with a 70 by 30 kilometres (43 mi × 19 mi) dome that rises 2–3 kilometres (1.2–1.9 mi) above the surrounding terrain. Another distinct local anomaly crosses Samhain Catenae. It overlaps with a large dome within Kirnis and a 2 kilometres (1.2 mi) high dome to the southwest. ^{[2] : 741–742}

See also

• Yamor Mons – A mountain on Ceres whose name was changed from Ysolo Mons in 2016

References

1. "Hanami Planum". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program. (Center Latitude: 15.00, Center Longitude: 230.00°; Planetocentric, +East)
2. Raymond, C. A.; et al. (August 2020). "Impact-driven mobilization of deep crustal brines on dwarf planet Ceres". Nature Astronomy. 4: 741–747. Bibcode:2020NatAs...4..741R. doi:10.1038/s41550-020-1168-2.
3. "Dawn at Ceres". NASA. Archived from the original on 17 May 2025. Retrieved 2 November 2025.
4. "Erntedank Planum". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program. No longer approved.
5. Buczkowski, Debra L.; et al. (2018). "The geology of the Occator quadrangle of dwarf planet Ceres: floor-fractured craters and other geomorphic evidence of cryomagmatism". Icarus. 316: 128–139. Bibcode:2018Icar..316..128B. doi:10.1016/j.icarus.2017.05.025. S2CID   134030861.
6. "Hanami Planum on Ceres". NASA. 23 March 2018. Retrieved 29 November 2025.
7. King, Scott D.; et al. (June 2022). "Ceres' Broad-Scale Surface Geomorphology Largely Due To Asymmetric Internal Convection". AGU Advances. 3 (3). Bibcode:2022AGUA....300571K. doi: 10.1029/2021AV000571 . e2021AV000571.
8. Buczkowski, Debra L.; et al. (December 2018). "Floor-Fractured Craters on Ceres and Implications for Interior Processes". Journal of Geophysical Research: Planets. 123 (12): 3188–3204. Bibcode:2018JGRE..123.3188B. doi: 10.1029/2018JE005632 .
9. "Studying Earth's Gravity Field from Space" (PDF). NASA. 2001. Retrieved 30 November 2025.