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Hartwig Crater is a crater in the Argyre quadrangle of Mars, located at 39° south latitude and 16° west longitude. It is 105 km in diameter and was named after Ernst Hartwig, a German astronomer (1851–1923). Impact craters generally have a rim with ejecta around them, in contrast volcanic craters usually do not have a rim or ejecta deposits. As craters get larger (greater than 10 km in diameter) they usually have a central peak.〔http://www.lpi.usra.edu/publications/slidesets/stones/〕 The peak is caused by a rebound of the crater floor following the impact. If one measures the diameter of a crater, the original depth can be estimated with various ratios. Because of this relationship, researchers have found that many Martian craters contain a great deal of material; much of it is believed to be ice deposited when the climate was different.〔Garvin, J., et al. 2002. Global geometric properities of martian impact craters. Lunar Planet Sci. 33. Abstract @1255.〕 Image:Wikihartwig.jpg|West side of Hartwig Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). The smaller crater is on the rim of Hartwig Crater. Image:Wikihartwigtongue.jpg|Tongue-shaped glaciers from previous image of Hartwig Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). Arrows indicate the tongue-shaped glaciers. Image:Wikihartwigmiddle.jpg|Middle section of Hartwig Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). Image:Wikihartwig.jpg|Channels on northern wall of Hartwig, as seen by CTX camera (on Mars Reconnaissance Orbiter). Note: this is an enlargement of the previous photo of the middle section of Hartwig Crater. Image:Hartwig Crater.JPG|Hartwig Crater Floor, as seen by HiRISE. The scale bar is 500 meters long. == See also == 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hartwig (Martian crater)」の詳細全文を読む スポンサード リンク
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