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takyon [soylentnews.org] writes:

Bright Areas on Ceres Suggest Geologic Activity [nasa.gov]

Since Dawn arrived in orbit at Ceres in March 2015, scientists have located more than 300 bright areas on Ceres. A new study in the journal Icarus, led by Nathan Stein, a doctoral researcher at Caltech in Pasadena, California, divides Ceres' features into four categories.

The first group of bright spots contains the most reflective material on Ceres, which is found on crater floors. The most iconic examples are in Occator Crater, which hosts two prominent bright areas. Cerealia Facula, in the center of the crater, consists of bright material covering a 6-mile-wide (10-kilometer-wide) pit, within which sits a small dome. East of the center is a collection of slightly less reflective and more diffuse features called Vinalia Faculae. All the bright material in Occator Crater is made of salt-rich material, which was likely once mixed in water. Although Cerealia Facula is the brightest area on all of Ceres, it would resemble dirty snow to the human eye.

More commonly, in the second category, bright material is found on the rims of craters, streaking down toward the floors. Impacting bodies likely exposed bright material that was already in the subsurface or had formed in a previous impact event.

Separately, in the third category, bright material can be found in the material ejected when craters were formed.

The mountain Ahuna Mons gets its own fourth category -- the one instance on Ceres where bright material is unaffiliated with any impact crater. This likely cryovolcano [nasa.gov], a volcano formed bythe gradual accumulation of thick, slowly flowing icy materials, has prominent bright streaks on its flanks.

Ceres [wikipedia.org] and cryovolcanos [wikipedia.org].

The formation and evolution of bright spots on Ceres [sciencedirect.com] (open, DOI: 10.1016/j.icarus.2017.10.014) (DX [doi.org])

Previously: A Closer Look At Mystery Spots On Dwarf Planet Ceres [soylentnews.org]
NASA's Dawn Orbiter Finds a Mountain on Ceres [soylentnews.org]
Ceres's Cryovolcanoes Viscously Relax Into Nothingness [soylentnews.org]
Organic Molecules Found on Ceres [soylentnews.org]
Dawn Mission Extended at Ceres [soylentnews.org]
Ceres May Have Had a Global Surface Ocean in the Past [soylentnews.org]

Original Submission