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[Music]

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yeah my name is Charlie lineweaver this

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is work that I've done with my PhD

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student hi young one whose image is

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right there unfortunately he couldn't

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come so it's about the D volatilization

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that leads to rocky planets and I showed

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a picture of the comet here because

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that's a good example of D

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volatilization of material as it comes

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closer to the Sun all right so lots of

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stars in our galaxy half these are half

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a billion of the 300 billion in the

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galaxy and bunk and stars form in the

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clumps in molecular clouds in the plane

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of the galaxy and as you can see from

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this when you have a bunch of stars here

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particularly the OB stars they are

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putting out lots of UV and they're

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creating these fingers everywhere so

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that's an example of the D

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volatilization in a molecular cloud so

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here's an accretion disk and so here for

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example that tiny accretion disk in this

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OB over here pushing away this gas here

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you can see dust is blocking out the

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star here and we're getting lots of

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volatiles along these Jets and here's a

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picture of what's going on essentially

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we were moving good gas and leaving the

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dust

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now here's another picture you may have

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heard that when these protoplanetary

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discs are there and they're trying to

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create that start turns on it's blowing

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out the volatiles from the interior and

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that's essentially what is responsible

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for the rocky planets that will end up

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there and so we have to spend lots and

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lots of planets lately there's a few

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thousand from the red ones our cups the

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red ones are from Kepler and and they're

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different techniques here here's the

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earth like once the rocky ones are down

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here in general and we would we so we

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know the mass we know their period we

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also if we have transit and radial

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detections we can get their density and

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that's what this plot is about so dense

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this is a slightly older plot but lots

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and lots of new planets are being put on

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here because we're getting more planets

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that we know both the radial velocity

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and the and the transits for so dense

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high density low density now one example

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of AD volatilized piece of

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stellar nebula is the earth and so when

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we plot the earth compared to the Sun

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you can see that did some elements

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particularly the noble gases there's

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very very little in the earth than blue

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and other elements which are very

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refractory you can see that the Earth's

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relative abundance and the Suns are

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pretty much identical almost in other

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words if we didn't have this star the

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Sun right there but we knew the

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abundances of the earth we could look

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around at all the stars and by matching

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the refractory elements we could figure

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out which was our mother star so now

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here a bunch of stars unfortunately this

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also is an older plot but the point is

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that stars differ in their relative

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abundances of different elements so you

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can see here that there now if there

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just a line up here that means they have

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high metallicity but the same relative

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abundances down here if it were just a

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line it would be low metallicity but the

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same relative abundances as the Sun but

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you can see that these lines go up and

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down up and down and so you get

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variations of 10 20 30 percent in the

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abundances of magnesium calcium other

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important elements that eventually will

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produce the rocky planets around that

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star so the name of the game then is to

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figure out what is let's may it be as

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precise as we can - what is the D

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volatilization that has produced the

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earth from the stellar nebula and here's

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a plot now normally earth scientists

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when they look at this these are the

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experts in Earth's what they plot here

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is see eyes up everybody's making this

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mistakes see eyes here as a

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representative of the Sun and they

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normalize - magnesium and they get a

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refractory thing here this says the

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earth and the Sun are the same and then

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there's this D volatilization here

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typically they don't use the bulk earth

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they use the primitive mantle and so we

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said oh you know what we're going to do

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a better job than these earth scientists

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first of all we're going to put error

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bars on the bulk earth and we're going

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to include the core and so we're going

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to get the elemental abundances of the

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earth with air bars and that has never

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been done before

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it's been almost done but we use what

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has been done before and did a better

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job of combining things and we think we

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have the best bulk elemental composition

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of the earth ever and you should use it

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in your future if you're interested in

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the

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is abundance normalized to aluminum now

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and aluminum is much more refractory

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than the silicon in the magnesium that I

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usually use so therefore you don't get

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that artificial increase in the you

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don't get an enrichment of the

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refractory elements and here what's

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plotted is the earth the concordant bulk

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earth in the blue and then we've also

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done what has usually been done as we

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did the primitive mantle dividing it

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into these types different element types

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and you can see that flat here and

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there's a line here so I said well you

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know what we got a flat here and a line

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here let's fit this has it been fit

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before kind of but not really so let's

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do the best job of fitting this line

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this D volatilization trend as we call

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it and when you do well first of all

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there's a difference when you look at

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plots like this make sure are they

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normalizing to see icon rights or are

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they normalizing to the Sun there's a

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difference a lot of things are the same

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but there's a very important differences

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for example here's the cut here's the C

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icon dried abundances here the solar

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photosphere abundances and you can see

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it's basically the same except for

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lithium is being burned in the Sun and

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all these have been depleted in CI

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chondrites

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plus CI contracts they have a lot of

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refractories it's the most volatile rich

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sometimes called the primitive

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meteorites that we use as a proxy for

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the Sun but in terms of these elements

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are really bad proxy so let's continue

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so highly volatile elements are nine and

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the depleted in CIS and are well

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determined in the photosphere 13

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elements without photosphere abundances

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are well determined in the meteoritic

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abundances primordial ism is burned in

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the Sun and so the whole idea is how do

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you combine

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photosphere with CI measurements to make

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the best measurements for the Sun and

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that's what we did and here's our method

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now laughter's 2009 did something very

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similar here's how she divided up those

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elements that combined them here's how

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we did this is the elements that are you

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based only on the photosphere elements

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based only on meteorites laughter's

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loves meteorites so she put most of them

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here but we did a

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average them this a stands for average

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so we average all these elements because

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both photo spheric and meteoritic

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abundances are available for those

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elements okay so when you do that you

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get a plot that looks like this but you

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can see it better down here

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the blue is photosphere the red are the

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CI chondrites and the yellow is the way

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we've combined them together to get the

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best estimate of the protis solar

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abundances and that's what we need

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because the proto solar abundances are

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what was d volatilized to produce the

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earth okay so along the way we figured

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eh why don't we do the XY and Z these

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are the mass fractions in hydrogen

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helium and everything else and it's

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interesting to know that over the last

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three decades this Z the amount the

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fraction of material in the Sun that's

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not hydrogen helium has been going down

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from one point eight nine all the way

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down to about one point four oh right

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here now when you plot up this now the

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Sun so here is the Sun and the blue is

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the earth and you can see that they're

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up and down up and down some of them are

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identical and some of them are developed

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alized some of them are really developed

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eyes and when you plot that as a

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function of condensation temperature

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this is notice this is linear

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condensation temperature not log you get

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something looks like here all this

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identical dental dead of all it goes

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down a little bit and there goes has

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this line here and then it goes soups

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down here a blow-up of this area is

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right here and you can see that it's up

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and down up and down up and down and

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then it starts to go down right about

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here so if you normalize to silicon or

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magnesium you're pumping this all up

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artificially and then you say oh it's

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enriched in little phial that's just an

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artificial product of your normalization

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okay so let's fit this line now this is

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pretty much the main result and that is

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we have here the Sun the new values of

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the Sun as I described we have here the

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bulk earth so where we really are

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comparing the proto Sun with the bulk

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earth and then we have this line here

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and what's an interesting feature is

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where does this line cross this line and

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that we spend some time to get this and

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it's 1 3 9 1 plus or minus 15 Kelvin

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here's the is to blow-up of that right

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moving along now let's compare what I

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just showed you two previous closest

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things and there are some things here

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from Carlin Lewis 93 palma no deal 2014

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mcdonough 2014 and basically they had

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this enrichment that I told you about

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when we renormalized there there's two

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aluminum for example that brings them

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all down here and then here's our 1391

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and here are their values right here so

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this would outside the error bars of our

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so we think we have the most precise

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measurement of some temperature that I

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don't think has a name I've asked lots

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of our sites what's the name of this

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temperature so we just called the D

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volatilization temperature or the brake

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temperature with a critical temperature

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beyond which you have flat here and then

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go down here now let's look now notice

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in this plot here the we have 500 is the

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lowest value of the condensation

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temperature for the next one and this is

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a log value of PC condensation

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temperature but now we're going to go

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further down and you can see that this

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balloon line which is established here

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we've just extrapolated it out here

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now one thing you could do when you

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extrapolate it out here you can say oh

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look at that this the mercury in the

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earth looks like it's over abundant

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compared to this line what could be

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wrong well what's wrong is that there is

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no measurement of photosphere of mercury

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so we just assume it's been from the sea

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ice and when you do that you get a

274
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miscalculation here but with you I have

275
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five minutes okay so if you say you know

276
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what let's not assume that the mercury

277
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this seemed like this pretty volatile

278
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thing is the same in CIS and the

279
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protosun then you get then you bring

280
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this down to here and you get much more

281
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Corden's all your in discussion time

282
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okay you're in the question time okay I

283
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will stop in about a minute I guess the

284
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point is that when you extrapolate here

285
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you get some noble gases which don't fit

286
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that line very well they're all depleted

287
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here and I we suspect that the

288
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condensation temperatures of oh and C

289
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are not right because Lauder's

290
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condensation temperatures are due to an

291
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equilibrium gas that's cooling and at

292
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equilibrium and I suspect we're talking

293
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about really non equilibrium in other

294
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words we have big chunks of material

295
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that's coming into the crease

296
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that is not it's not like an onion well

297
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it's not that equilibrium I just say

298
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that and it gets sublimated and what

299
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else I want to say and see it well

300
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that's they're probably different values

301
00:11:36,280 --> 00:11:34,130
for PC for Owens and C and what else so

302
00:11:38,820 --> 00:11:36,290
we also looked at this in terms of the

303
00:11:41,200 --> 00:11:38,830
CIS and we got some kind of condé

304
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volatilization temperature for CIS as

305
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you can see that they're very close to

306
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the Sun and then they diverge right here

307
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and I'm running out of time we

308
00:11:49,720 --> 00:11:48,170
recalibrated to see I just have a look

309
00:11:52,360 --> 00:11:49,730
at it from another way and we have the

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Sun going up the CIA or Moises to the

311
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one and then the last slide is to first

312
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order the earth is a dibala five pieces

313
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of solar nebula

314
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similarly rocky exoplanets are most

315
00:12:03,010 --> 00:12:01,790
certainly develop lies piece of the

316
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stellar net without of which they in

317
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their host stars form by comparing the

318
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compositional difference between premise

319
00:12:09,490 --> 00:12:08,150
on and earths we have quantified the

320
00:12:10,480 --> 00:12:09,500
first-order develop relation patterns

321
00:12:12,880 --> 00:12:10,490
that can be used to estimate the

322
00:12:14,470 --> 00:12:12,890
chemical composition of rock EXO planets

323
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around other stars because we have those

324
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other stars elemental abundances by

325
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doing spectrum thank you

326
00:12:33,939 --> 00:12:32,559
Charlie very interesting talk I

327
00:12:34,929 --> 00:12:33,949
definitely want to talk to you and get

328
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your slides afterwards

329
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um are you oh I'm sorry Carolus Johns

330
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Hopkins Applied Physics Laboratory old

331
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friends of Charlie for many years I

332
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would be a little worried about your gia

333
00:12:47,530 --> 00:12:46,369
volatility and temperatures you're

334
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assuming for carbon hydrogen oxygen

335
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nitrogen as you know John elements can

336
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combine into many different materials

337
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all of which have usually are vastly

338
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different evaporation temperatures so

339
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you may want to make that part of your

340
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problem is bulk carbon it isn't just

341
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both oxygen and graphic exactly I

342
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completely agree with you that's why we

343
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have these little but what we can do is

344
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figure out what those condensation

345
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temperatures are for right here for

346
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example we can say okay let's pretend

347
00:13:15,369 --> 00:13:13,189
that they fit what does that say about

348
00:13:17,259 --> 00:13:15,379
the different elements in a in them and

349
00:13:18,540 --> 00:13:17,269
it's a little bit like well I suspect

350
00:13:21,669 --> 00:13:18,550
that that will give more accurate

351
00:13:23,619 --> 00:13:21,679
distributions of these elements rather

352
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than the ones that were put in by waters

353
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when she did a calculation skeeved and I

354
00:13:31,119 --> 00:13:29,179
show you this is really fantastic it's a

355
00:13:33,939 --> 00:13:31,129
very much needed thing so I'm very

356
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excited also to get a preprint or

357
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something I wanted to do the same thing

358
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and what I ran into that for sadirah

359
00:13:41,470 --> 00:13:39,529
files they're all in the core and we

360
00:13:44,019 --> 00:13:41,480
don't know what's in the core and for

361
00:13:45,610 --> 00:13:44,029
refractories very often they actually

362
00:13:46,660 --> 00:13:45,620
just assume the abundances of the

363
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Santa's chondrites

364
00:13:50,259 --> 00:13:47,899
how did you get around those problems

365
00:13:51,639 --> 00:13:50,269
well one thing is the first thing we had

366
00:13:54,220 --> 00:13:51,649
to do is figure out what the mass

367
00:13:56,499 --> 00:13:54,230
fraction of the core is is there about

368
00:13:58,059 --> 00:13:56,509
four four things that the four papers

369
00:13:59,619 --> 00:13:58,069
have been written but earth scientists

370
00:14:01,809 --> 00:13:59,629
are convinced that they don't need to

371
00:14:04,480 --> 00:14:01,819
put air bars so we said oh there have

372
00:14:06,460 --> 00:14:04,490
four just we have four numbers for the

373
00:14:09,879 --> 00:14:06,470
mass fraction of the core so you need to

374
00:14:12,850 --> 00:14:09,889
know is that 32 into 33 is it 31 and we

375
00:14:14,829 --> 00:14:12,860
looked at that carefully and combined

376
00:14:16,150 --> 00:14:14,839
results and then we had to use a new

377
00:14:17,379 --> 00:14:16,160
gravitational constant too because the

378
00:14:18,730 --> 00:14:17,389
total mass of the Earth has changed

379
00:14:21,009 --> 00:14:18,740
because little big G has changed a

380
00:14:23,470 --> 00:14:21,019
little bit so these are tiny well I

381
00:14:26,110 --> 00:14:23,480
would say significant but usually

382
00:14:28,660 --> 00:14:26,120
detailed differences also you're right

383
00:14:30,280 --> 00:14:28,670
that the MOT it's model dependent but

384
00:14:31,749 --> 00:14:30,290
there are about seven models so what we

385
00:14:32,980 --> 00:14:31,759
did is say well there's a model there's

386
00:14:34,720 --> 00:14:32,990
a model there's a model for what the

387
00:14:35,949 --> 00:14:34,730
composition of the core is and then we

388
00:14:37,119 --> 00:14:35,959
just said okay let's take the upper and

389
00:14:39,189 --> 00:14:37,129
lower error bar and say that's the

390
00:14:40,509 --> 00:14:39,199
uncertainty in the composition of the

391
00:14:41,050 --> 00:14:40,519
core which we then add to the primitive

392
00:14:42,400 --> 00:14:41,060
mental

393
00:14:43,600 --> 00:14:42,410
you're right the primitive man slit

394
00:14:46,210 --> 00:14:43,610
everybody knows about it because it's

395
00:14:49,300 --> 00:14:46,220
more accessible but there are many many

396
00:14:50,830 --> 00:14:49,310
ways to model not get great estimates

397
00:14:53,050 --> 00:14:50,840
for the core but the best ones that

398
00:14:54,730 --> 00:14:53,060
exist and that's the ones we used okay

399
00:14:56,740 --> 00:14:54,740
we'll talk with error bars that are

400
00:14:58,570 --> 00:14:56,750
legitimate really reflect how much the

401
00:15:01,030 --> 00:14:58,580
people who are modeling the course think

402
00:15:02,770 --> 00:15:01,040
they know about it in other words don't

403
00:15:04,630 --> 00:15:02,780
just oh we can't do anything about it I

404
00:15:06,100 --> 00:15:04,640
think that's just uh that's what

405
00:15:07,360 --> 00:15:06,110
everybody in their sciences community

406
00:15:09,340 --> 00:15:07,370
has done so far because they don't keep

407
00:15:11,180 --> 00:15:09,350
track of their error bar let and your oh