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I was reading an article by David O'Brien et al. where it stated

"in meteorites only the water bound to the silicates can be found, all the water ice having been lost, whereas on asteroids water ice itself has been detected"

https://www.sciencedirect.com/science/article/pii/S0019103514002620

Now this was published in 2014, so I'm wondering what is the validity of this statement today. Have we, since the publication of this article, discovered water ice on meteorites?

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It looks to me that you probably have some misunderstanding of the term meteorite. A meteorite is a remnant body which has reached the surface of a major or minor body (a planet, a moon, an asteroid, etc.). The meteorite's parent body (a meteoroid) would definitely lose its entire water ice (if it had any at all) no later than during its passage through the Earth's atmosphere. That's why no water ice was or will ever be found in meteorites.

So, unless you compare common meteorite impacts with hazardous asteroid impacts, these two body types are incomparable as water ice carriers. And thus, the statement by O'Brien et al still stands firm and will do so ever.

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  • $\begingroup$ O'Brien also states "In addition, water vapor has been discovered coming from Ceres (Kuppers et al., 2014) and water ice has been observed on the surface of Themis (Campins et al., 2010, Rivkin and Emery, 2010), suggesting that the water content of primitive asteroids, small and large, is substantially larger than that recorded in meteorites." Do you agree with this statement? He seems to be comparing the water content on meteorites and asteroids. $\endgroup$ – Bell Aug 17 '18 at 4:07
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    $\begingroup$ Of course, you can compare water content on any types of bodies in general; so, yes, I agree with him. But in my answer I meant something different, that this comparison is obviously meaningless if you try to figure out which of the two bodies could have brought water on Earth. It is an obvious thing, because just imagine bodies ranging from grain-sized meteoroids up to Ceres-sized asteroids: theoretically only a huge asteroid's remnant mass could still have some water ice inclusions after the impact (I'd doubt that, though), while a common meteorite would never have it simply due to its size. $\endgroup$ – SergiusPro Aug 17 '18 at 4:28
  • $\begingroup$ Has water ice been found on comets? Or is this unique to larger bodies, like asteroids? $\endgroup$ – Bell Aug 17 '18 at 6:43
  • $\begingroup$ Yes, there is a plenty of water ice and other ice types in/on comets. Any solid space body can have it to a larger or smaller degree. $\endgroup$ – SergiusPro Aug 17 '18 at 14:16
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    $\begingroup$ @Bell - A larger object has the potential to carry more water and an object burning up in the atmosphere was no potential to have surface ice; though past or present H$_2$O may be detected. Japan is landing on asteroid Ryugu, see the Haya2kun Twitter they have almost landed. It appears dry. Maybe there's a bit of ice, it may not be water ice, or maybe there's no ice at all; each are different. NASA's article: "Asteroid or Meteor: What's the difference?" - see their asteroidmission.org . $\endgroup$ – Rob Aug 17 '18 at 17:00

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