Tir Planitia

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Tir Planitia
Tir Planitia m10 aom 8 10.gif
Mariner 10 image showing scarps in the southeast Tir Planitia region of Mercury. These scarps may be volcanic flow features or compressional faults. The frame is about 130 km across
Planet Mercury
Coordinates 0°48′N176°06′W / 0.8°N 176.1°W / 0.8; -176.1
Quadrangle Tolstoj
Eponym Persian word for Mercury

Tir Planitia is a large plain on the planet Mercury. The name Tir (تیر) is the Persian word for "Mercury", [1] , and the name was approved in 1976. [2] It was first observed in detail by Mariner 10. [3] It lies between the large crater Mozart and the ancient Tolstoj basin.

Tir Planitia is one of four named plains that surround the Caloris basin (with Mearcair Planitia, Stilbon Planitia, and Odin Planitia). All of these plains are classified as smooth, as opposed to intracrater plains which have rougher topography. They also contain areas where kilometer-scale knobs protrude above the plains, and these areas are called the Odin Formation. The Odin Formation is interpreted as a mixture of impact melt and blocky basin ejecta, formed by the Caloris impact event. [4]

The crater Fet is near the center of Tir Planitia. Hovnatanian crater is southwest of Fet. The craters Amru Al-Qays and Nureyev are in northern Tir Planitia.

Related Research Articles

<span class="mw-page-title-main">Caloris Planitia</span> Crater on Mercury

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.

<span class="mw-page-title-main">Geology of Mercury</span> Geologic structure and composition of planet Mercury

The geology of Mercury is the scientific study of the surface, crust, and interior of the planet Mercury. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is analogous to the field of terrestrial geology. In planetary science, the term geology is used in its broadest sense to mean the study of the solid parts of planets and moons. The term incorporates aspects of geophysics, geochemistry, mineralogy, geodesy, and cartography.

<span class="mw-page-title-main">Odin Planitia</span> Geologic basin on Mercury

Odin Planitia is a large basin on Mercury. It was named after the Norse god Odin in 1976 by the IAU. It was first observed in detail by Mariner 10. The plain is approximately 473 kilometers in diameter.

<span class="mw-page-title-main">Borealis quadrangle</span> Quadrangle on Mercury

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.

<span class="mw-page-title-main">Goethe Basin</span> Crater on Mercury

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.

<span class="mw-page-title-main">Tolstoj quadrangle</span> Quadrangle on Mercury

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.

<span class="mw-page-title-main">Shakespeare quadrangle</span> Quadrangle on Mercury

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.

<span class="mw-page-title-main">Michelangelo quadrangle</span> Quadrangle on Mercury

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.

<span class="mw-page-title-main">Mozart (crater)</span> Crater on Mercury

Mozart is a crater on Mercury, named by the IAU in 1976 after Austrian composer Wolfgang Amadeus Mozart.

<span class="mw-page-title-main">Rembrandt (crater)</span> Crater on Mercury

Rembrandt is a large impact crater on Mercury. With a diameter of 716 km it is the second-largest impact basin on the planet, after Caloris, and is one of the larger craters in the Solar System. It was discovered by MESSENGER during its second flyby of Mercury on October 6, 2008. The crater is 3.9 billion years old, and was created during the period of Late Heavy Bombardment. The density and size distribution of impact craters along Rembrandt's rim indicate that it is one of the youngest impact basins on Mercury.

<span class="mw-page-title-main">Oskison (crater)</span> Crater on Mercury

The crater Oskison is located in the far northern hemisphere of Mercury, in the plains north of Caloris basin. Oskison is a distinctive crater with a large central peak that exposes material excavated from depth. Many chains of secondary craters are visible radiating from Oskison outward onto the surrounding smooth plains, known as Stilbon Planitia.

<span class="mw-page-title-main">Hovnatanian (crater)</span> Crater on Mercury

Hovnatanian is a crater on Mercury. Its “butterfly” pattern of ejecta rays were created by an impact at an even lower angle than that which formed neighboring Qi Baishi crater. From the "butterfly" pattern of rays, the Hovnatanian impactor was travelling either north-to-south or south-to-north prior to hitting Mercury's surface. Hovnatanian lies to the west of Tir Planitia.

<span class="mw-page-title-main">Raditladi (crater)</span> Crater on Mercury

Raditladi is a large impact crater on Mercury with a diameter of 263 km. Inside its peak ring there is a system of concentric extensional troughs (graben), which are rare surface features on Mercury. The floor of Raditladi is partially covered by relatively light smooth plains, which are thought to be a product of the effusive volcanism. The troughs may also have resulted from volcanic processes under the floor of Raditladi. The basin is relatively young, probably younger than one billion years, with only a few small impact craters on its floor and with well-preserved basin walls and peak-ring structure. It is one of 110 peak ring basins on Mercury.

<span class="mw-page-title-main">Rachmaninoff (crater)</span> Crater on Mercury

Rachmaninoff is a impact crater on Mercury. This basin, first imaged in its entirety during MESSENGER's third Mercury flyby, was quickly identified as a feature of high scientific interest, because of its fresh appearance, its distinctively colored interior plains, and the extensional troughs on its floor. The morphology of Rachmaninoff is similar to that of Raditladi, which is one of the youngest impact basins on Mercury. The age of Raditladi is estimated at one billion years. Rachmaninoff appears to be only slightly older.

<span class="mw-page-title-main">Amru Al-Qays (crater)</span> Crater on Mercury

Amru Al-Qays is a crater on Mercury. The crater was first imaged by Mariner 10 in 1974. Its name was adopted by the IAU in 1976, after the pre-Islamic Arab poet Imru' al-Qais in honor of his impact on astronomy and the world.

<span class="mw-page-title-main">Kālidāsā (crater)</span> Crater on Mercury

Kālidāsā is a crater on Mercury. Its name was adopted by the International Astronomical Union in 1976. Kalidasa is named for the Indian writer Kālidāsa, who lived in the 5th century CE.

<span class="mw-page-title-main">Inter-crater plains on Mercury</span>

Inter-crater plains on Mercury are a land-form consisting of plains between craters on Mercury.

<span class="mw-page-title-main">Mearcair Planitia</span> Planitia on Mercury

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.

<span class="mw-page-title-main">Stilbon Planitia</span> Planitia on Mercury

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.


  1. Grego, Peter (2008). Venus and Mercury, and how to Observe Them. Springer. p. 48. Retrieved 27 August 2020.
  2. "Tir Planitia". Gazetteer of Planetary Nomenclature. IAU/NASA/USGS . Retrieved 20 August 2023.
  3. SHADED RELIEF MAP OF THE TOLSTOJ QUADRANGLE OF MERCURY, Atlas of Mercury, NASA Special Publication 432, 1978.
  4. Denevi, B. W., Earnst, C. M., Prockter, L. M., and Robinson, M. S., 2018. The Geologic History of Mercury. In Mercury: The View After MESSENGER edited by Sean C. Solomon, Larry R. Nittler, and Brian J. Anderson. Cambridge Planetary Science. Section 6.3.3.