Concentric Craters

[astroavani]

Concentric craters

Can you forget Endyminon for a moment and focus on a small detail?

Look at the picture carefully and see if you notice something different.

Realized that little concentric crater just below Endymion?

It is part of a very special group of craters that still generate a large debate.

This concentric crater still unassigned and about 6.5 km of the arrow in the picture, caught my attention because it is a classic concentric and still have a small craterelet almost exactly in the center thus giving the whole a target print. This can be seen in the picture attached in 3D obtained from the Quick Map.

The Concentric Craters, or DC, are smaller Moon features that have been ignored at least for some 30 years. But now some scientists examined these features again. David Trang University of Hawaii and colleagues Jeff Gillis-Davis, Ray Hawke and Ben Bussey, published and recently presented a paper at the Lunar & Planetary Science Conference, where they report that found 14 more CCs than a previous list made 30 years ago, using it for data from the Clementine, Kaguya and LRO probes to distinguish and confirm the identified features. Almost all the researchers now agree that the main crater is a small impact crater, normal and the question is whether the inner ring or torus is formed in association with the impact or is the result of some endogenic modification (endogenic is a word that It means that something has been created internally rather than created by external forces). The group of David found evidence against the hypothesis that the torus is formed by a simultaneous double layered impact in the target by volcanic activity or viscous relaxation. They noted that the distribution of CC along the edges of the seas is very similar to the fractured inside craters. As it is believed that the interior Fractured craters are impact craters modified by igneous intrusions, they proposed without details that these intrusions can also modify the interior of CCs. This is consistent with evidence that the CCs have a spectral signature virtually identical to the material located beyond the crater rim, implying that there was at least this point, volcanic extrusions. David showed this with the DC Firmicus C crater 14 kilometers in diameter, as an evocative example of volcanic material that can be associated with CC but mostly is not visible. The small dark spot on the torus seems to be pyroclastic excavated by small impact crater. It will be interesting to follow the work of these researchers and see if they will be able to find the same type of feature in other CCs and if they can develop an explanation of how an intrusion would create the morphology of the CC.

Source: Space Today

Adaptation and text: Avani Soares

http://www.astrobin.com/full/235942/0/

[nightfisher]

Very sharp, lovely images, been a long time since i had a chance to Luna image

[Pete Presland]

Difficult to forget Endyminon as you have done such a good job of imaging it   but you are right that is a fascinating little crater below it and thank you for the detailed explanation.

[Ruud]

Thank you, Avani.

The image is wonderful and the CC is enigmatic indeed! I enjoyed reading the explanation. Thank you for referring to QuickMap's 3D feature. I had not yet discovered that.

Of course I experimented a bit with the 3D views of the CC. On the top-left is the CC together with nearby Endymion K, an impact crater of about the same size. The CC looks completely different! In this view, the CC appears to have a third, incomplete, middle ring of hills.

There is also a low angle view of the CC, which shows how shallow it is. Endymion K is more than four times as deep according to the line tool of QuickMap.

The last view is from straight over head. The centre of the CC is littered with sink holes, if that is what they are, and the most prominent of the hills in the middle ring now looks like a small volcano. I marked it with a V on the screenshot.

It is a truly remarkable feature. It would seem that a bubble of lava lifted the region and then subsided, leaving the outer ring. Then the pressure of the lava increased again again to form a smaller blister in the centre and an incomplete ring of volcanic domes in the fractured crust around it. Finally, the lava subsided again, forming the middle ring and the sink holes in the centre.

Or someone threw a brick in the mud.

Thank you for pointing out this puzzling feature!

[astroavani]

Very interesting their conclusions friend Ruud! I'm glad that this post has served to feed his curiosity as you realize that you are endowed with great insight. I will suggest your text as read to some colleagues who are discussing this in other places.

[laudropb]

Lovely images and a very interesting report. I have looked at this area a few times, but to my shame have never noticed this. At the next favourable occasion I must revisit. In the meantime some research is called for. Thanks for pointing this out.

[cloudnine]

I first noticed one of these in Humboldt very recently. Intriguing little objects aren't they.

Thanks for the heads-up of the latest research.... very interesting to follow this. And thanks for posting a most excellent image!

Martin

[michael.h.f.wilkinson]

Lovely detail shots of an intriguing feature