Hellas Planitia


Also found in: Wikipedia.

Hellas Planitia

(hell -as) A vast, roughly circular impact basin in Mars' southern hemisphere, located in the planet's southern highland region at the areographic coordinates 40° S latitude, 290° W longitude (see areography). It can be seen as a bright area from the Earth and is the largest impact feature on the planet. It is thought to be the result of an asteroidal impact about 3900 million years ago during the heavy bombardment phase of the formation of the Solar System. The crater excavated by the asteroid is about 9 km deep and 2100 km in diameter and is girdled by a ring of material forming an elevated rim that reaches a height of about 1.5 kilometers above the level of the surrounding area. See Mars, surface features.
References in periodicals archive ?
An image captured by the HiRISE camera on April 22 showed a series of strange chevron symbols that appear to resemble the iconic "Star Trek" Starfleet logo on a Martian sand dune in the southeast Hellas Planitia region. 
Using satellite images, researchers spotted fields of ghost dunes pitting the surface of two different regions on Mars: 480 potential dune molds at Noctis Labyrinthus, a mazelike region of plateaus and canyons, and 300 in the Hellas Planitia, a smooth 4-billion-year-old crater.
These remanent fields are absent from Hellas Planitia as well as several other large impact basins.
A series of sedimentary deposits indicates the presence of large standing bodies of water in Hellas Planitia located in the southern hemisphere of Mars, said by Dr.
The space agency's (https://www.nasa.gov/image-feature/jpl/pia22052/squiggles-in-hellas-planitia) Jet Propulsion Laboratory shared a photo of the lines, made in Mars' Hellas Planitia, that its Mars Reconnaissance Orbiter took as it was surveying the area - part of an almost 1,400-mile-wide impact basin on the planet's southern hemisphere that is the largest one ever found in the solar system.
Even at the bottom of the Hellas Planitia, the largest impact crater in the solar system, the pressure is estimated at just 1.1% of Earth standard.