Editing 16 Psyche (section)

===Features===
[[File:Psyche illustration.jpg|thumb|Illustration of Psyche commissioned by NASA]]

Many features have been reported on Psyche. The largest of these are regions of mass-deficits relative to its nominal ellipsoid shape and are reminiscent of the [[Rheasilvia (crater)|Rheasilvia]] basin on [[4 Vesta]].<ref name="Shepard2021" /><ref name="Ferrais-Vernazza-etal-2020" /><ref name="Viikinksk-Vernza-etal-2018" /><ref name="Shepard-Richardson-etal-2017" />

In addition to the large-scale regions of mass-deficit, several apparent craters have been reported. Observers using the [[Very Large Telescope]]'s [[adaptive optics]] [[SPHERE]] imager reported two large craters, on the order of 90&nbsp;km across, which were provisionally named Meroe {{IPAc-en|ˈ|m|ɛr|oʊ|iː}} and Panthia {{IPAc-en|ˈ|p|æ|n|θ|i|ə}},{{citation needed|date=October 2020}}<!-- not clear this is the same name. If the ‘I' is long in Latin, it would be \pan-THY-a\ --> after the twin witches in the Roman novel [[The Golden Ass|''Metamorphoses'' by Apuleius]].<ref name="Zimmerman_mythology"/><ref name=Viikinksk-Vernza-etal-2018/> Observers using the [[Arecibo Telescope|Arecibo Radar Telescope]] reported craters at the south pole (referred to as Delta),<ref name="Shepard-Richardson-etal-2017" /> southern midlatitudes (referred to as Eros),<ref name="Shepard-Richardson-etal-2017" /><ref name="Shepard2021" /> and the north pole (referred to as Foxtrot).<ref name="Shepard2021" /> An analysis of the features present in several independent shape models suggests that craters Panthia and Eros are almost certainly real and Foxtrot is likely to be real. However, there is uncertainty over the existence of Meroe and Delta.<ref name="Shepard2021" />

Early lightcurve studies suggested that Psyche has large variations in its surface brightness.<ref name="Dotto1992"/> These variations became more evident when attempts were made to invert lightcurves to generate shape models.<ref name="Kaasalainen-etal-2002" /><ref name="Shepard-Richardson-etal-2017" /> The most recent shape models based on lightcurve inversions simultaneously solve for surface albedo variations,<ref name="Viikinksk-Vernza-etal-2018" /><ref name="Ferrais-Vernazza-etal-2020" /> and the resulting maps show regions where local albedo differs from the mean albedo by more than 20% in either direction. Notably, the Meroe crater coincides with an area much darker than the mean, and the Panthia crater coincides with an area much brighter than the mean.

Radar observations with the [[Arecibo Telescope|Arecibo Radar Telescope]] revealed that Psyche's "background" [[Albedo#Radar Albedo|radar albedo]] is <math>\hat{\sigma}_{OC}=0.26 </math>, comparable to other [[M-type asteroid]]s like [[21 Lutetia]].<ref name="Shepard2021" /> This value is consistent with a [[Silicate mineral|silicate]] (rocky) regolith enriched in metal phases.<ref name="Shepard2015"/> However, in at least three locations, Psyche's radar albedo is nearly twice this value, suggesting high concentrations of metal phases in these regions.<ref name="Shepard2021" /> One of these locations corresponds with the optically bright Panthia crater, while the other two correspond with regions that have been reported as optically bright.<ref name="Ferrais-Vernazza-etal-2020" /><ref name="Viikinksk-Vernza-etal-2018" /><ref name="Shepard2021" /> This apparent correlation between optical and radar albedos on Psyche has led to the hypothesis that there is a link between the process(es) that create regions of high metal content and brighter terrain.<ref name="Shepard2021" />

{{multiple image
| align = right
| direction = vertical
| total_width = 220
| image1 = Psyche features Shepard2021.jpg | caption1 = Shape model of asteroid 16 Psyche, with some of the observed surface features indicated.
| image2 = Psyche albedo Shepard2021.jpg |thumb | caption2 = Optical albedo map of asteroid 16 Psyche with superimposed radar albedo measurements (circles).
}}