Hermite
Topographic map of Hermite (center) by LRO's laser altimeter
Coordinates86°10′N 93°19′W / 86.17°N 93.32°W / 86.17; -93.32
Diameter108.64 km
DepthUnknown
Colongitude110° at sunrise
EponymCharles Hermite[1]
Lunar Orbiter 4 image of Hermite and surrounding craters

Hermite is a lunar impact crater located along the northern lunar limb, close to the north pole of the Moon. Named for Charles Hermite, the crater was formed roughly 3.91 billion years ago.[2]

Physical features

Hermite is a worn, eroded crater with a rugged outer rim that is notched and incised from past impacts. A crater overlies the southwestern rim, and the two formations have merged to share a common interior floor. A pair of small craters lies along the southern part of the rim, and a small crater is also attached near the northern end. The interior floor has been resurfaced, so that it forms a wide plain that is pock-marked by numerous tiny craterlets and low hills. There is a small crater on the floor near the northeastern wall.

In 2009, it was discovered by NASA's Lunar Reconnaissance Orbiter that Hermite is the coldest place recorded in the solar system, with temperatures at 26 kelvins (−413 °F, −247 °C).[3] For comparison, Pluto's surface only gets down to about 43 kelvins (−382 °F, −229 °C).[4]

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Hermite.

Hermite Coordinates Diameter
A 87°48′N 47°06′W / 87.8°N 47.1°W / 87.8; -47.1 20 km
B 87°08′N 86°12′W / 87.14°N 86.2°W / 87.14; -86.2 8.4 km[5]

Hermite A

Possible water ice presence

There may exist a large amount of water ice within Hermite A's permanently shadowed region (PSR), where no light from the sun ever reaches; according to a 2016 study published by the IEEE roughly two-thirds of the crater's PSR is covered with varying amounts of ice.[6] However, a 2018 study also published by the IEEE countered this claim, arguing that the method used to detect ice in the earlier study was not refined enough to conclusively identify a material as ice, and that more detailed methods were needed to determine if ice exists within Hermite A.[7] A further analysis of the crater in 2022 using data from the Chandrayaan-1 and Chandrayaan-2 lunar orbiters found that ice may exist in clusters on the walls and some parts of the floor of Hermite A.[8]

References

  1. ^ Hermite, Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)
  2. ^ Arya, A.S.; et al. (October 2011). "Surface age and morphology of Hermite crater of lunar North Pole using high resolution datasets". EPSC-DPS Joint Meeting 2011. Division for Planetary Sciences & European Planetary Science Congress. 2011: 1850. Bibcode:2011epsc.conf.1850A. Retrieved 27 August 2022.
  3. ^ Amos, Jonathan (16 December 2009). "'Coldest place' found on the Moon". BBC. Retrieved 17 December 2009.
  4. ^ Williams, Ryan (3 January 2006). "Pluto Colder Than Expected". Space.com. Retrieved 27 May 2011.
  5. ^ Fa, Wenzhe; Cai, Yuzhen (11 July 2013). "Circular polarization ratio characteristics of impact craters from Mini-RF observations and implications for ice detection at the polar regions of the Moon". Journal of Geophysical Research: Planets. American Geophysical Union. 118 (8): 1582–1608. Bibcode:2013JGRE..118.1582F. doi:10.1002/jgre.20110. S2CID 130297816. Retrieved 28 August 2022.
  6. ^ Calla, O.P.N.; Mathur, Shubhra; Gadri, Kishan Lal (July 2016). "Quantification of Water Ice in the Hermite-A Crater of the Lunar North Pole". IEEE Geoscience and Remote Sensing Letters. Institute of Electrical and Electronics Engineers. 13 (7): 926–930. Bibcode:2016IGRSL..13..926C. doi:10.1109/LGRS.2016.2554282. ISSN 1558-0571. S2CID 31374007.
  7. ^ Liu, Niutao; Fa, Wenzhe; Jin, Ya-Qiu (23 July 2018). "No Water–Ice Invertable in PSR of Hermite-A Crater Based on Mini-RF Data and Two-Layers Model". IEEE Geoscience and Remote Sensing Letters. Institute of Electrical and Electronics Engineers. 15 (10): 1485–1489. doi:10.1109/LGRS.2018.2852139. ISSN 1558-0571. S2CID 52902076. Retrieved 27 August 2022.
  8. ^ Singh, Awinash; et al. (10 May 2022). "Dielectric characterization and polarimetric analysis of lunar north polar crater Hermite-A using Chandrayaan-1 Mini-SAR, Lunar Reconnaissance Orbiter (LRO) Mini-RF, and Chandrayaan-2 DFSAR data". Advances in Space Research. Elsevier. 70 (12): 4030–4055. Bibcode:2022AdSpR..70.4030S. doi:10.1016/j.asr.2022.04.059. S2CID 248710695. Retrieved 27 August 2022.

External links

Further reading

Categories