October 21, 2015
Rough Domes
Originally published October 20, 2004
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Image Credit: Paolo Lazzarotti |
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Rough Domes The Arago domes are probably the best known compact volcanic piles on the Moon, and because they are relatively large structures, have been imaged many times. You might wonder if we can learn anything new from yet another image of the domes and this area, and Paolo's image demonstrates the answer is, "Yes!" The high image scale and resolution of today's LPOD reveal complexities of the Arago Alpha and Beta domes. Arago Beta has a basic round shape with a breeched crater-like depression on its northern side, making the dome look like a beetle with pincers. On the west (left) side of the dome there is another roundish lobe, like a small companion dome (arrowed on mouseover). A similar smaller dome (arrow) occurs on the north side of Arago Alpha, but slightly further away so it looks more like a separate structure. Alpha also is seen to have two tiny but steep peaks near its center and an elongated depression extends northward from the brightest peak. Between Arago Alpha and the crater Maclear are three domes of about the same size as the domes next to Alpha and Beta, and in the NE corner of the image are three smaller features (arrows) that also appear to be domes. It is interesting that all of the domes in this area look somewhat similar to each other, but different from the classical hemispherical, pitted domes near Hortensius and elsewhere on the Moon. These SW Tranquillitatis domes have formed in basalts of relatively high TiO2 abundance (7.5-10%) - perhaps dome morphology is related to basalt types. Finally, there is a broad and long ridge between Arago D and E that would be called a dome if it were not so elongated. This image also nicely shows the Sosigenes rilles and a smaller one NW of Arago that I hadn't seen before. Large image scale, high resolution and low sun seem to be the keys for discovering new features on the maria. Technical Details: Related Links: Yesterday's LPOD: Rays of Light Tomorrow's LPOD: 60 Inches of Tycho |
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