Caloris Planitia is a plain within a large impact basin on Mercury, informally named Caloris, about 1,550 km (960 mi) in diameter. It is one of the largest impact basins in the Solar System. "Calor" is Latin for "heat" and the basin is so-named because the Sun is almost directly overhead every second time Mercury passes perihelion. The crater, discovered in 1974, is surrounded by the Caloris Montes, a ring of mountains approximately 2 km (1.2 mi) tall.
Budh Planitia is a large plain on Mercury. It lies to the east of Odin Planitia. It falls within the Tolstoj quadrangle. It was named after the Hindu word for Mercury, Budha, in 1976.
Tir Planitia is a large plain on the planet Mercury. The name Tir (تیر) is the Persian word for "Mercury",, and the name was approved in 1976. It was first observed in detail by Mariner 10. It lies between the large crater Mozart and the ancient Tolstoj basin.
The Borealis quadrangle is a quadrangle on Mercury surrounding the north pole down to 65° latitude. It was mapped in its entirety by the MESSENGER spacecraft, which orbited the planet from 2008 to 2015, excluding areas of permanent shadow near the north pole. Only approximately 25% of the quadrangle was imaged by the Mariner 10 spacecraft during its flybys in 1974 and 1975. The quadrangle is now called H-1.
Goethe Basin is an impact basin at 81.4° N, 54.3° W on Mercury approximately 317 kilometers in diameter. It is named after German poet Johann Wolfgang von Goethe.
The Tolstoj quadrangle in the equatorial region of Mercury runs from 144 to 216° longitude and -25 to 25° latitude. It was provisionally called "Tir", but renamed after Leo Tolstoy by the International Astronomical Union in 1976. Also called Phaethontias.
Tolstoj is a large, ancient impact crater on Mercury. It was named after Leo Tolstoy by the IAU in 1976. The albedo feature Solitudo Maiae appears to be associated with this crater.
The Shakespeare quadrangle is a region of Mercury running from 90 to 180° longitude and 20 to 70° latitude. It is also called Caduceata.
The Caloris group is a set of geologic units on Mercury. McCauley and others have proposed the name “Caloris Group” to include the mappable units created by the impact that formed the Caloris Basin and have formally named four formations within the group, which were first recognized and named informally by Trask and Guest based on imagery from the Mariner 10 spacecraft that flew by Mercury in 1974 and 1975. The extent of the formations within the group have been expanded and refined based on imagery and other data from the MESSENGER spacecraft which orbited Mercury from 2011 to 2015, and imaged parts of the planet that were in shadow at the time of the Mariner 10 encounters.
The Bach quadrangle encompasses the south polar part of Mercury poleward of latitude 65° S. It is named after the prominent crater Bach within the quadrangle, which is in turn named after Baroque composer Johann Sebastian Bach. The quadrangle is now called H-15.
The Raditladi quadrangle (H-4) is one of fifteen quadrangles on Mercury. It runs from 270 to 180° longitude and 20 to 70° latitude. Named after the Raditladi Basin, it was mapped in detail for the first time after MESSENGER entered orbit around Mercury in 2011. It had not been mapped prior to that point because it was one of the six quadrangles that was not illuminated when Mariner 10 made its flybys in 1974 and 1975. These six quadrangles continued to be known by their albedo feature names, with this one known as the Liguria quadrangle.
Beethoven is a crater at latitude 20°S, longitude 124°W on Mercury. It is 630 km in diameter and was named after Ludwig van Beethoven. It is the eleventh largest named impact crater in the Solar System and the third largest on Mercury.
The Eminescu quadrangle (H-9) is one of fifteen quadrangles on Mercury. It runs from 216 to 288° longitude and from -25 to 25° latitude. Named after the Eminescu crater, it was mapped in detail for the first time after MESSENGER entered orbit around Mercury in 2011. It had not been mapped prior to that point because it was one of the six quadrangles that was not illuminated when Mariner 10 made its flybys in 1974 and 1975. These six quadrangles continued to be known by their albedo feature names, with this one known as the Solitudo Criophori quadrangle.
The Debussy quadrangle (H-14) is one of fifteen quadrangles on Mercury. It runs from 270 to 360° longitude and from -20 to -70° latitude. Named after the Debussy crater, it was mapped in detail for the first time after MESSENGER entered orbit around Mercury in 2011. It had not been mapped prior to that point because it was one of the six quadrangles that was not illuminated when Mariner 10 made its flybys in 1974 and 1975. These six quadrangles continued to be known by their albedo feature names, with this one known as the Cyllene quadrangle.
The Neruda quadrangle (H-13) is one of fifteen quadrangles on Mercury. It runs from 180 to 270° longitude and -20 to -70° latitude. Named after the Neruda crater, it was mapped in detail for the first time after MESSENGER entered orbit around Mercury in 2011. It had not been mapped prior to that point because it was one of the six quadrangles that was not illuminated when Mariner 10 made its flybys in 1974 and 1975. These six quadrangles continued to be known by their albedo feature names, with this one known as the Solitudo Persephones quadrangle.
The Michelangelo quadrangle is in the southern hemisphere of the planet Mercury, where the imaged part is heavily cratered terrain that has been strongly influenced by the presence of multiring basins. At least four such basins, now nearly obliterated, have largely controlled the distribution of plains materials and structural trends in the map area. Many craters, interpreted to be of impact origin, display a spectrum of modification styles and degradation states. The interaction between basins, craters, and plains in this quadrangle provides important clues to geologic processes that have formed the morphology of the mercurian surface.
Mozart is a crater on Mercury, named by the IAU in 1976 after Austrian composer Wolfgang Amadeus Mozart.
Mearcair Planitia is a large plain on the planet Mercury. The name Mearcair is the Irish word for "Mercury", and the name was approved in 2017. It was first observed in detail by MESSENGER. It lies between the large crater Raditladi and the ancient Caloris basin.
Stilbon Planitia is a large plain on the planet Mercury. The name Stilbon is ancient Greek word for "Mercury", and the name was approved in 2017. It was first observed in detail by MESSENGER. It lies north of the Caloris basin, and is approximately 1550 kilometers long.
