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my name is Emma you I'm from University

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of Texas at Austin I want to first send

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the organizers for having me here I've

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been having fun learning a lot over the

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weekend so I work with Neil Allen cell

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doesn't Robinson Caramella see and neyo

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turn around this project so first I'll

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give a really quick review on or

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understanding of protoplanetary disc red

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star formation and then I'll move on to

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our attempt to find the optically thin

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tracer for the dismay play Liriano I'll

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talk about our finding and our modeling

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approach so first of all this is my

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version of the start and information

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picture borrow from actually Jeff's left

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side okay so single star formations

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start from the caps of very very dense

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core and molecular cows because there is

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some sort of rotation at the very

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beginning so materials can only fall

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allowing the rotation axis but not

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perpendicular to it so we end up with

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the rotating disk around the newly

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formed youngstarr this stage is very

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valid after probably 100,000 years we

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enter relatively stable state what we

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call T Tauri face around solar-type

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stars so this stage plus for a few

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million years for solar-type stars and

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with a relatively mild equation rate of

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10 to the minus eight solar mass per

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year after this relatively stable stage

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the disk enter very rapid a dissipation

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stage actually the next speaker is going

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to talk more about that so this will

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dissipate in around 100,000 years if

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you're lucky we live with the live with

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the planetary system we actually seen

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those disks in many different

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wavelengths in many different situations

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so the poem upper left side this is the

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HST Hubble image of the scatter light of

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the disk surface so we're seeing here is

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the central stars for somewhere around

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here the life hit on the disservice is

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scattered into our telescope the problem

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is were only seeing that

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surface we can only tell properties from

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a very very surface little disk through

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this kind of image another really

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dominated way of seeing those disks

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actually lives there has be a lot of

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progress made in the past 15 years is by

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observing the infrared sed s so what

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we're seeing here is a function of

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energy outside is the luminosity the

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energy as a function of the wavelength

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so we're seeing a really broad spectrum

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this part it makes it an inner part of

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this and other part of a disk but the

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problem is we want this to be relatively

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warm you're going to show up in this

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loop and so again we're seeing the

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relative warm surface and the inner part

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of the Jesse self so with the

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development of amazing interferometry is

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we're beginning to see molecular lying

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wishes from those disks so the most

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common leveraging is 12 CEO just because

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CEO is everywhere and there's a mission

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straight strong the problem is again the

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lines are a click so we're only seeing

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the very surface of the disk but in

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order to entice them plan information we

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want to be see inside out of the

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district line cuz that's where plan

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informations are actually happening so

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we try to ask some really fundamental

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questions like how massive the distance

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that's available for plan information it

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turns out we don't know that very well

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so first of all our understanding is

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heavily biased toward our solar system

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the zero order magnitude approximation

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is to simply smear out the matter for

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known planets so we have mercury various

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planets out here we just smear it out

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over the orbits and then we add up the

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ball is health just lost during planet

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formation process so we add up the

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oxygen the hydrogen stuff like that the

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may end up with the surface density

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distribution which is a the surface

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density as a function of distance to the

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central star and this is your prime I

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mean were lower limit or like the basic

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picture

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of the solar nebula but there's a

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problem with this picture because we

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assume everything we see today was the

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case when it was first formed I'm Zoey

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assume one hundred percent daily

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attention which is obviously not the

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case Moses you know planets or form in

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situ so they've their form where we see

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they are right now which we now found as

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not the case planets migrate all the

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time another way of seeing this is to

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observe disks around other stars so

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traditionally this has been done by

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observing dust emissions okay the

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problem with this approach is we observe

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those discs in submillimeter so that

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we're only most sensitive to dust grains

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up around the same size when no dust

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grains grow up into pebbles into folders

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once they grow into larger bodies they

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are less invasive in those business so

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we're now able to see them anymore so

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we're really only seeing a small

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fraction of this mess from this approach

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annoyingly the result from the dust

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emissions or a minimum a solar nebula

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agree with each other radio a well but

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we know both of them are probably wrong

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so we try to ask the question what if we

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just measure the dispatch directly from

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the gas phase as Brandon just mentioned

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ninety-nine percent of this mess it's

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actually in the gas phase so there has

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been done before once this HD with

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deuterium because that's the last

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pendant as the top of hydrogen the

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problem with that is that was done with

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her show her shows dad is gone it does

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not exist anymore and also this line

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requires relatively high excitation

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temperature so it's sensitive not just

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to the amount of material out there also

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to the temperature of the disk however

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this example told us is important to

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measure the distance from the gas phase

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because the math day Frank was actually

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heavier than what people people to

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really find from dust emission is also

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way better than minimum a solar nebula

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so our goal is to find the rare optical

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we're sorry I stole a rare molecule in

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order to allow us to trace directly to

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the dismay plan allow us to measure the

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dispatch from the gas phase so we want

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to use this awesome array alma of

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doubling chili so that we have so so

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that we can have enough sensibility

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sensitivity to probe very very wicked

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missions it turns out that's a really

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hard thing to do just in order to build

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a model right just because the

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temperature the dead seed chemistry

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immediately transfer there Oh cobble

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together so it breaks the mold down into

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three components so ask me about a

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details later but right now I'm just

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going to focus on the big components so

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we model the thermo dynamical evolution

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of the disc by putting in MRI again the

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next speaker is going to talk more about

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that and then we recalculate the

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evolution of density and temperature in

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each individual grade point and then

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running chemical model on the top of it

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so we care about where as a top lock so

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we need to consider say you very

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structures and self shouting and

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photochemical reactions stuff like that

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so we did that and then we end up with a

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profile of chemical dependence

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temperature and density for every single

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point in the disk for three million

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years and then we run radius transfer

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model on the top of it and try to

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estimate the output depths of those

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molecules so this is the temperature

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profile to take away unpleasing oh so

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imagine the torus of the disk this here

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is the central star and now we're taking

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a cross-section of the disk so this the

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x axis is the distance from the central

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star so the stars here and this is the

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thickness and the height so the disk

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surface is hated by the central star and

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the heat propagates down so that's why

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it's hotter here right means hot sorry

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this is the temperature in Kelvin and

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the takeaway here is equation heating

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doesn't matter that much easier does

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dollars that's actually different from

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what people have been assuming and take

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away from chemistry is in our dismal

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that we actually don't see Co face

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outcomes the heating from the central

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star is pretty efficient but we do see a

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drop of sea abandons due to the

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formation or organics so carbon alpha is

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primarily in the ice form that's

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inherited from the cloud and the CEOs go

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so rad means a lot Blue means almost

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nothing and this is the badness of

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normalized by the amount of total portal

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never danske so we're seeing a lot of

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complicated organic molecules it exactly

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what kind of organic were seeing depends

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on the model and the initial conditions

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but we tested with input from

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observational data and also from

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Wellington it seems that this result is

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pretty robust okay um so last year for

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sorry two years ago there was a big

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discussion I mean discovery itself

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imaging co Iceland in the polyp into

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this that's really cool because we can

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use that as a direct temperature tracer

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people don't have time to talk about it

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so we're only trying to see if we're

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only trying to say if they don't see Co

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around it doesn't necessarily mean that

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cos resell on the gray surface there can

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be something else yeah so after doing

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all this we sit down and estimate lack

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of depth of different cos o top logs and

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here we're seeing a the octo depth in

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vertical direction for face out geometry

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so you're seeing a disk facing right

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from for you as a function of the

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distance from the central star and it

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turns out that sees 70 know the blue

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line here is a brief AVL Pollock tourney

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at you and see 18yo is ugly thing beyond

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1780 I believe so we hope to use that

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line in order to measure the dispatch

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with el Mazo we proposed for

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psycho 3 tired we'll see how that goes

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so the idea is this this will be a line

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profile this is the velocity just

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because the disk is rotating so save

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this part is moving towards you oh the

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inner part of this rotates faster so

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that goes to the line shoulder and then

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the other part road takes a little bit

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slower so that goes in in the war so we

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have a double pick signature for a disc

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and we can translate the luminosity the

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intensity of those lines and back to the

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amount of material that's gaming up the

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emissions so that's where we'll go I'll

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leave the conclusion here and take

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questions thank you so that was really

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cool I'm wondering if the result that co

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can turn into complex organics in the

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disk is a new results and if so what

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does that imply is it possible to

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directly look at organics with also or

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what's the future for that the problem

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is it would be really hard for us to see

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them the way it happens is we actually

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see the growth of carbonate in the gas

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phase and then it's easier for those

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organs to freeze out of the green

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surface so they will freeze on the grace

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and just get out of the gas phase

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reaction Network but when Kari news is

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people are seeing the depletion of

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carbon in the gas phase I think as well

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as oxygen so they're thinking about okay

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carbon might go to something somewhere

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else and it could well be there again

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excelent surface so it's encouraging

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it's encouraging that people are seeing

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observationally already yeah I I have

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one so what are the prospects for

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imaging rare isotope log snow minds with

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Alma is it gonna be yeah actually I

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think this is unpublished result people

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are seeing it alright yes I'll poster

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from typer

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group they have c18 eau de don t leave a

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hydro so they are seeing a Iceland actor

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here you exactly where yeah that's def a

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creep are saying I mean into h plus and