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[Music]

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so thanks for introduction this is

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probably the longest title of the

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mouthful so I explain a characterization

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with James Webb ticularly focused about

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the Chaplin system and I'm gonna give us

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a little bit about introduction to that

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which is great because I'm gonna zip

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through the introduction really fast

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because I have a lot of stuff to show

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so the key big picture here is that M

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dwarfs are about three-quarters of the

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stars in our local group so if you're

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thinking about the distribution of life

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and astrobiologist both in the solar

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system and beyond

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you kind of want an idea about where

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life might exist in the local universe

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and chances are good that you're gonna

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be looking at an EM door around four

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planets around other stars so the other

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good piece of information here is that

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the Kepler statistics show us that M

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dwarf stars are more likely to are very

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likely to have planets around all of

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them and the stars that do have planets

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are likely to have multiple planets

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that's really great and because these M

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dwarf stars are small and red and cooler

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they're a lot easier to observe planets

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around them because that transit method

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right you're looking for earth-size

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planet and if you're around a smaller

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dimmer star so much easier to see that

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signal so that's really the only way

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that will observe terrestrial AXA

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planets around other stars in the next

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20 years is with James Webb but M dwarf

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stars have their own problems that other

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stars may not have and that's a very

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long super luminous premium sequence

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phase so for up to a billion years while

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the star and planets are forming the

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star is much brighter than it will

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eventually be and so planets that are in

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the habitable zone for the main-sequence

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phase during the pre main-sequence phase

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they can boil off you know tens or

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hundreds of oceans and build up to

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thousands of bars of or atmospheres of

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oxygen and this is a serious issue for

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these planets actually having life

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eventually in addition to this pre

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main-sequence phase the last so long you

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have life long stellar activity that can

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continue to sterilize the surface and

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strip off the atmosphere so that's

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that's maybe a bad sign so if you're so

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with that information then you ask how

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could M dwarf planets even have life how

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could they even have an atmosphere so we

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need to start asking some of these

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questions to be able to see if these are

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even great things to look at for

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astrobiology so our first question might

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be do these planets even have an

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atmosphere that's kind of the first bit

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of information you want when you observe

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them next might be are these massive

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oxygen atmospheres I'm talking about

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which are just theorized at this point

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right we don't have an oxygen a mass of

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oxygen planet in our solar system we

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just have a life based oxygen around

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Earth that's also a problem for a false

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false bio signature right so are those

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types of planets even possible or a

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common even or do you get a more venous

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like planet looking at our solar system

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we know a Venus like planet can exist

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and this is a post runaway greenhouse

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planet are these perhaps the most common

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types of planets around or star or and

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perhaps the only way you can really get

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a habitable planet in the habitable zone

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of an M dwarf star is can you have some

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kind of mini Neptune a more hydrogen

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rich volatile rich planet can this

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migrate in during formation strip off

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its hydrogen envelope and leave you with

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a habitable evaporated core which is

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positive if you used to go by Richard

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Lugar at all so spectral observations by

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James Webb will help us distinguish or

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show whether these types of planets can

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occur and distinguish among them

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hopefully

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so we've already heard a little bit

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about Trappist one this is a great

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system I'll just hit it briefly again

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three planets inside the inner edge of

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the habitable zone three planets within

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the conservative habitable zone at least

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one planet beyond the outer edge so this

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gives you a great single system to look

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at planetary evolution among seven

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different targets which is really great

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so just the first of my talk I'm going

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to talk about the climate model and the

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chemistry model I use show some of the

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modeling results in terms of the

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atmospheres and their structures and

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their chemistry and then go into some of

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the spectral signatures which is really

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the point of the work I'm doing so the

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model I use is a 1d climate model this

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is a very rigorous line-by-line

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radiative convective model and whose

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multi scattering off so it's a great

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stuff that you use to you can model

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earth and all the solar system plans

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with these this is coupled to a photo

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chemical kinetics model because as I

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said M dwarfs have really crazy UV and

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so in order to really understand what

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might happen to an atmosphere around

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them core if you have to understand what

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the UV is doing to the chemical

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species in the atmosphere once I've

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converged on a photochemical and climate

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equilibrium state then this uses the

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exact same radio transfer models

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prettiest very high-resolution spectra

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that can then be get degraded and so you

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can see what they might look like for

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James Webb so when we're considering

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what kind of atmosphere is I'm modeling

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I'm mostly modeling thick evolved

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atmospheres right atmospheres that have

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evolved from the primordial composition

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this spans from a recent ocean loss type

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system where we said okay it just lost

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its water from the pre main sequence

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phase and perhaps you're just left with

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mostly oxygen and then perhaps if that

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planet was not totally desiccated from

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its interior that it might have

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outgassing like earth right greenness

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like IO then you have other constituents

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that are volcanic that can be emitted so

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you can look at that and then all the

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way to the Venus like end of the

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spectrum where you just have a runaway

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greenhouse planet and this is what are

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you left with but since this is a

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astrobiology conference let's also

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consider what an earth-like planet might

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look like right all the other previous

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ones I showed are not really anything

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that we would expect life that we know

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it took to live on but I'm comparing

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this with an ocean bearing planet that

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perhaps could develop life so we can see

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if we can distinguish these now when I

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model these atmospheres and come up with

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the surface temperatures the story

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becomes more complicated the habitable

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zone is only a first-order indicator of

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habitability but if you stick different

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types of atmospheres on the same planet

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you end up finding that the habitable

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zone is not a guarantee of habitability

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you can have planets span from 600 PS

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600 Kelvin if you have a Venus like

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atmosphere all the way down to very low

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cold 180 Kelvin for just an oxygen

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atmosphere on a colder planet so this is

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kind of a problem but the habitable zone

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is still a place that is more likely

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alright knock with planet gives us some

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more cases so we have more good

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green-colored

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maybe habitable temperatures in the

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habitable zone than we have outside of

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it so it's still a good indicator

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now with the modeling results here's

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pressure and temperature structures and

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chemistry I'm just going to breeze

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through these really fast but just a

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couple important points

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the previous speaker talked about phase

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curves and that can tell you something

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about the temperature structure of the

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planet that's one way you can observe an

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oxygen planet is because there's no

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water the oxygen absorption actually

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creates a temperature inversion near the

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surface and this may be observable by a

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thermal phase curve but I'm not going to

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show any of those in this talk this

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these planets are otherwise

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distinguished by high ozone levels

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because there's no water to scrub out

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the ozone which happens in Earth's

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troposphere and the same thing you get

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carbon monoxide build up in the

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atmosphere

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you might be observable now if you have

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a little more outgassing with an oxygen

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planet you end up losing this

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temperature inversion at the surface you

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create a more typical terrestrial a tbat

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of a temperature but this is a lot

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warmer you get some some water in the

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atmosphere and this ends up going

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basically into it runaway greenhouse

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state as you can see where you have even

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more than you know point one percent

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water in the in the upper atmosphere

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indicating that the planets losing water

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but you get a lot less carbon monoxide

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and you get a little bit less buildup of

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ozone but this is still fairly

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substantial so that's pretty interesting

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then if we go to Venus like planet and

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as far as I know this is the first real

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EXO Venus modelling I've ever seen so

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yeah but you end up seeing that even a

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Venus around m-dwarf still looks kind of

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Venus like these white lines are the

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Venus ones in each color is the each

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planet you'll notice there's no Trappist

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1b here because the planet is too hot to

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actually form sulfuric acid clouds so

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that really is not going to be quite as

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Venus like and that's maybe good news or

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bad news for a couple of reasons but you

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see these planets can still form

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sulfuric acid clouds and here's the

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optical depth that I form in this

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photochemical model and so you still

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make it clouds which is if you've

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followed any of the exoplanet work with

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hubble space telescope that's might be a

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serious problem for anthing spectroscopy

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that I've burned through some of the

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climates let's look maybe more at what

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we act might actually observe so here's

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a very confusing spectra of

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Trappist one see the second planet with

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all of its cases I modeled so you have

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the oxygen cases down here and green and

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purple and then Venus light cases up

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here and yellow and red

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and what you see here is that first of

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all where is your signal coming from

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since like so the previous speakers have

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said your transit spectrum is light from

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within from the star not from the planet

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so it's passing through the atmosphere

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so that's where your stronger signal is

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so keep that in mind when you're looking

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at how big some of these features are

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and where the signal is but you get co2

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features right that goes back to our

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first question is how do we know these

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planets even have an atmosphere the most

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universal sign for a terrestrial planet

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is probably going to be carbon dioxide

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every planet I modeled had some carbon

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dioxide and carbon dioxide produces very

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strong signals and multiple wavelength

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bands so that's probably the first place

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to look for whether a planet has an

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atmosphere the next thing we might be

276
00:09:33,829 --> 00:09:31,019
interested in is a water signal for a

277
00:09:35,059 --> 00:09:33,839
planet like this in the inside in inside

278
00:09:37,280 --> 00:09:35,069
of inner edge of the habitable zone

279
00:09:39,259 --> 00:09:37,290
water is not necessarily a good sign

280
00:09:40,670 --> 00:09:39,269
these have very strong water features

281
00:09:42,619 --> 00:09:40,680
and this is actually sign that there's

282
00:09:43,879 --> 00:09:42,629
water in the stratosphere and so your

283
00:09:46,329 --> 00:09:43,889
planet is actually losing water so

284
00:09:48,860 --> 00:09:46,339
that's maybe not a good thing to see I

285
00:09:50,360 --> 00:09:48,870
mentioned the oxygen planets so you can

286
00:09:53,210 --> 00:09:50,370
actually distinguish these from their

287
00:09:54,530 --> 00:09:53,220
heavy oxygen so you get oxygen collision

288
00:09:55,850 --> 00:09:54,540
because the atmospheres are so dense and

289
00:09:57,019 --> 00:09:55,860
have sufficient oxygen for that so

290
00:09:58,420 --> 00:09:57,029
that's a signal we can actually look for

291
00:10:00,920 --> 00:09:58,430
as well

292
00:10:04,369 --> 00:10:00,930
ozone again is another thing that maybe

293
00:10:07,340 --> 00:10:04,379
might be an issue or false bio

294
00:10:08,749 --> 00:10:07,350
signatures and then you have other gases

295
00:10:10,939 --> 00:10:08,759
like sulfur dioxide which indicate

296
00:10:12,980 --> 00:10:10,949
volcanism and that is maybe a good or

297
00:10:15,230 --> 00:10:12,990
bad thing for what the planet is active

298
00:10:18,499 --> 00:10:15,240
geologically active or is this thing

299
00:10:19,970 --> 00:10:18,509
more venus like CEO also indicates

300
00:10:21,769 --> 00:10:19,980
desiccation so that's not good

301
00:10:23,509 --> 00:10:21,779
but so Trapattoni this is probably I

302
00:10:24,920 --> 00:10:23,519
think the literature is mostly an

303
00:10:27,579 --> 00:10:24,930
agreement that Trapattoni is probably

304
00:10:30,470 --> 00:10:27,589
the best target for trafficed one for

305
00:10:32,629 --> 00:10:30,480
potentially habitable planet and so I've

306
00:10:33,829 --> 00:10:32,639
plotted the Aqua planet as well and

307
00:10:36,230 --> 00:10:33,839
that's these two spectra down here and

308
00:10:37,309 --> 00:10:36,240
since their one bar their transmission

309
00:10:39,290 --> 00:10:37,319
Spectre get deeper into the atmosphere

310
00:10:41,689 --> 00:10:39,300
in fact deep enough to start seeing

311
00:10:43,579 --> 00:10:41,699
water features from the troposphere and

312
00:10:44,990 --> 00:10:43,589
in this case you can see that the water

313
00:10:46,610 --> 00:10:45,000
features are actually kind of similar if

314
00:10:48,410 --> 00:10:46,620
you look at the relative transit depth

315
00:10:49,780 --> 00:10:48,420
from the top of the Cygnus to the bottom

316
00:10:51,980 --> 00:10:49,790
of the signal they're roughly the same

317
00:10:53,449 --> 00:10:51,990
and that's because these even the

318
00:10:55,400 --> 00:10:53,459
runaway greenhouse planets have a little

319
00:10:56,749 --> 00:10:55,410
bit less water in their atmosphere so

320
00:10:58,460 --> 00:10:56,759
it's really hard to distinguish whether

321
00:11:00,819 --> 00:10:58,470
this planet has an ocean just from

322
00:11:03,079 --> 00:11:00,829
seeing a water feature in the atmosphere

323
00:11:05,299 --> 00:11:03,089
those own features a little bit smaller

324
00:11:06,649 --> 00:11:05,309
for an earth-like planet so that might

325
00:11:08,749 --> 00:11:06,659
be good but that really might be hard to

326
00:11:10,159 --> 00:11:08,759
distinguish but the other thing you get

327
00:11:12,499 --> 00:11:10,169
for an earth-like planet right is

328
00:11:13,429 --> 00:11:12,509
methane that's simply something Leavitt

329
00:11:15,229 --> 00:11:13,439
biologists study and though there's a

330
00:11:17,479 --> 00:11:15,239
methane talk later in the session

331
00:11:18,919 --> 00:11:17,489
and this is only a biotic levels of

332
00:11:21,169 --> 00:11:18,929
methane and it's still showing up as a

333
00:11:22,519 --> 00:11:21,179
signal in my spectra one thing if you're

334
00:11:24,199 --> 00:11:22,529
familiar with some of the other M dwarf

335
00:11:25,969 --> 00:11:24,209
Tresckow exoplanet literature is M

336
00:11:29,359 --> 00:11:25,979
dwarfs and dwarf planets have a lot

337
00:11:31,699 --> 00:11:29,369
higher capability of seeing more methane

338
00:11:32,809 --> 00:11:31,709
much more methane than earth gifts so

339
00:11:34,579 --> 00:11:32,819
this is actually earth bubbles of

340
00:11:36,529 --> 00:11:34,589
methane from only geological levels

341
00:11:38,179 --> 00:11:36,539
reflexes so you can imagine that these

342
00:11:42,019 --> 00:11:38,189
methane bands could be much stronger

343
00:11:44,359 --> 00:11:42,029
from an actual biosphere so those were

344
00:11:45,379 --> 00:11:44,369
beautiful perfect christine spectra even

345
00:11:47,959 --> 00:11:45,389
though they're really scary-looking

346
00:11:49,249 --> 00:11:47,969
there was no air bars on them so what

347
00:11:51,049 --> 00:11:49,259
happens when a telescope is actually

348
00:11:52,759 --> 00:11:51,059
trying to observe this planet this is

349
00:11:55,009 --> 00:11:52,769
gonna be a lot more difficult case and

350
00:11:56,989 --> 00:11:55,019
this is this one right here is trapezoid

351
00:11:58,549 --> 00:11:56,999
B the innermost planet probably the

352
00:12:01,099 --> 00:11:58,559
easiest to observe because the hottest

353
00:12:03,229 --> 00:12:01,109
it's fairly large compared to the other

354
00:12:06,889 --> 00:12:03,239
ones so this one produces very strong

355
00:12:10,099 --> 00:12:06,899
signals up to 200 parts per million from

356
00:12:12,499 --> 00:12:10,109
an instrument that has a noise floor of

357
00:12:13,879 --> 00:12:12,509
probably 30 parts per million so this

358
00:12:15,319 --> 00:12:13,889
you can actually see you can see the co2

359
00:12:17,239 --> 00:12:15,329
features you're looking at the dots you

360
00:12:19,249 --> 00:12:17,249
can see actually a water feature co2

361
00:12:21,469 --> 00:12:19,259
feature water so this is actually great

362
00:12:24,049 --> 00:12:21,479
and this is only ten occultation sort n

363
00:12:25,849 --> 00:12:24,059
transits to observe in this planet so

364
00:12:28,189 --> 00:12:25,859
that's actually doable with James Webb

365
00:12:30,289 --> 00:12:28,199
hopefully is that we have capability

366
00:12:31,869 --> 00:12:30,299
here perhaps observing this planet and

367
00:12:34,729 --> 00:12:31,879
actually seeing spectral features

368
00:12:35,749 --> 00:12:34,739
now I mentioned clouds before our clouds

369
00:12:37,219 --> 00:12:35,759
are a serious problem

370
00:12:39,949 --> 00:12:37,229
so let's look a Trappist one see which

371
00:12:41,479 --> 00:12:39,959
could form sulfuric acid clouds the

372
00:12:43,309 --> 00:12:41,489
cloud deck is right here right it

373
00:12:45,619 --> 00:12:43,319
truncates the transmission spectrum at

374
00:12:47,359 --> 00:12:45,629
the top of the cloud deck and so this is

375
00:12:49,849 --> 00:12:47,369
a serious problem because now our signal

376
00:12:52,459 --> 00:12:49,859
went from maybe 200 parts per million to

377
00:12:53,539 --> 00:12:52,469
now it's half that and so that's a lot

378
00:12:55,159 --> 00:12:53,549
more difficult and here's the number of

379
00:12:57,949 --> 00:12:55,169
occupations you'd have to get to several

380
00:12:59,989 --> 00:12:57,959
noise of five or ten fifteen for Travis

381
00:13:01,129 --> 00:12:59,999
Muncey for a Venus like atmosphere or if

382
00:13:03,829 --> 00:13:01,139
you have a Venus like atmosphere that

383
00:13:06,619 --> 00:13:03,839
actually has clouds now you're up to

384
00:13:08,209 --> 00:13:06,629
eighty and I don't think the James Webb

385
00:13:10,459 --> 00:13:08,219
committees have determined how much time

386
00:13:11,750 --> 00:13:10,469
is going we're ever going to approve

387
00:13:14,870 --> 00:13:11,760
eighty transit system

388
00:13:16,610 --> 00:13:14,880
like 100 200 hours of time on a very

389
00:13:20,720 --> 00:13:16,620
expensive telescope that has to compete

390
00:13:23,150 --> 00:13:20,730
with other science so now that was

391
00:13:27,230 --> 00:13:23,160
already really bad the habitable planet

392
00:13:28,580 --> 00:13:27,240
potentially trap us 1e this this looks

393
00:13:30,440 --> 00:13:28,590
pretty scary right you can see a co2

394
00:13:32,660 --> 00:13:30,450
band but this is fifty or a hundred

395
00:13:34,220 --> 00:13:32,670
transits of this planet to be able to

396
00:13:35,630 --> 00:13:34,230
see these features so this maybe is

397
00:13:37,010 --> 00:13:35,640
something that once we really understand

398
00:13:39,230 --> 00:13:37,020
the noise characteristics of James Webb

399
00:13:41,780 --> 00:13:39,240
and if it's favorable maybe this is

400
00:13:44,480 --> 00:13:41,790
something we can convince the observers

401
00:13:46,040 --> 00:13:44,490
in charge of the telescope to look at

402
00:13:48,350 --> 00:13:46,050
something like trap is running long

403
00:13:49,880 --> 00:13:48,360
enough to actually be able to

404
00:13:51,050 --> 00:13:49,890
distinguish an atmosphere in this plant

405
00:13:52,610 --> 00:13:51,060
otherwise if you just look at five

406
00:13:54,380 --> 00:13:52,620
transits and traffice or any you're not

407
00:13:57,800 --> 00:13:54,390
going to see anything and not gonna

408
00:13:58,310 --> 00:13:57,810
learn anything so what data do we have

409
00:13:59,900 --> 00:13:58,320
now

410
00:14:01,700 --> 00:13:59,910
Korea's speaker Arthur mentioned

411
00:14:04,280 --> 00:14:01,710
photometry so we did look at the

412
00:14:07,190 --> 00:14:04,290
photometric bands from Spitzer and

413
00:14:09,290 --> 00:14:07,200
Kepler that are available and we find

414
00:14:12,080 --> 00:14:09,300
that our models kind of fit the data

415
00:14:14,180 --> 00:14:12,090
here but the Spitzer bands Spitzer

416
00:14:16,310 --> 00:14:14,190
really struggles with seeing at rest

417
00:14:19,070 --> 00:14:16,320
reply that they tried this really

418
00:14:21,800 --> 00:14:19,080
doesn't rule out anything straight-line

419
00:14:23,000 --> 00:14:21,810
my spectra hey but at least they're kind

420
00:14:25,390 --> 00:14:23,010
of going the right way

421
00:14:28,130 --> 00:14:25,400
but that's probably confirmation bias

422
00:14:30,920 --> 00:14:28,140
but everything's still consistent so

423
00:14:32,690 --> 00:14:30,930
everything's still available I think it

424
00:14:35,840 --> 00:14:32,700
out of time now so I'll just leave up my

425
00:14:37,430 --> 00:14:35,850
conclusions primarily that extent

426
00:14:38,780 --> 00:14:37,440
activity drives the composition of the

427
00:14:39,890 --> 00:14:38,790
atmosphere to drive the photochemistry

428
00:14:41,750 --> 00:14:39,900
and I charged with climbin what you

429
00:14:43,550 --> 00:14:41,760
might observe and that these planets

430
00:14:45,050 --> 00:14:43,560
while they may be observable by James

431
00:14:47,600 --> 00:14:45,060
Webb with features up to 200 parts per

432
00:14:48,950 --> 00:14:47,610
million for the most favorable cases we

433
00:14:50,600 --> 00:14:48,960
really have to consider hard our

434
00:14:52,280 --> 00:14:50,610
observing strategy for the smaller

435
00:14:57,300 --> 00:14:52,290
planets and whether we'll be able to

436
00:14:57,310 --> 00:15:06,900
[Applause]

437
00:15:06,910 --> 00:15:12,360
any questions do your left

438
00:15:16,300 --> 00:15:14,740
so pretty much hmm pretty much all of

439
00:15:18,550 --> 00:15:16,310
these planets are in some sort of mean

440
00:15:19,090 --> 00:15:18,560
motion resonance and probably all tied

441
00:15:21,880 --> 00:15:19,100
and they live

442
00:15:24,640 --> 00:15:21,890
yep how do you does the model account

443
00:15:26,860 --> 00:15:24,650
for a lack or a possible some amount of

444
00:15:28,840 --> 00:15:26,870
circulation between them and do you see

445
00:15:30,700 --> 00:15:28,850
big variations in the day and night side

446
00:15:32,470 --> 00:15:30,710
spectra so I don't model the day or

447
00:15:34,420 --> 00:15:32,480
night side this is a 1d model I am

448
00:15:36,880 --> 00:15:34,430
working on a kind of day and night side

449
00:15:39,000 --> 00:15:36,890
type model to be able to do more

450
00:15:42,490 --> 00:15:39,010
difficult planets that way I've done

451
00:15:46,000 --> 00:15:42,500
some comparison from work on Proximus NB

452
00:15:50,110 --> 00:15:46,010
on comparing 1d to 3d models and so

453
00:15:53,560 --> 00:15:50,120
forth ich say atmosphere is like Venus

454
00:15:57,240 --> 00:15:53,570
that have very good thermal capabilities

455
00:15:59,890 --> 00:15:57,250
there you can actually find that see

456
00:16:01,060 --> 00:15:59,900
that yeah so like one of the sums that

457
00:16:04,870 --> 00:16:01,070
were shown is that okay if you have a

458
00:16:06,430 --> 00:16:04,880
resonance your atmosphere is can be

459
00:16:08,500 --> 00:16:06,440
smeared out so the day/night side is

460
00:16:10,840 --> 00:16:08,510
quite similar and that's one reason why

461
00:16:12,400 --> 00:16:10,850
we can use a 1d model here I found that

462
00:16:13,720 --> 00:16:12,410
the temperatures and when you're looking

463
00:16:15,579 --> 00:16:13,730
at the surface temperatures which is

464
00:16:17,650 --> 00:16:15,589
primarily what I'm looking at in terms

465
00:16:19,180 --> 00:16:17,660
of habitability that the surface

466
00:16:21,460 --> 00:16:19,190
temperatures that the 3d modelers got

467
00:16:24,310 --> 00:16:21,470
from the LM D model from próxima son

468
00:16:26,140 --> 00:16:24,320
were quite repetitive all in 2016 under

469
00:16:28,420 --> 00:16:26,150
the exact same assumptions for the 1d

470
00:16:31,329 --> 00:16:28,430
model they get very similar answers

471
00:16:33,190 --> 00:16:31,339
within 5 or 10 Kelvin in most cases the

472
00:16:35,260 --> 00:16:33,200
other thing to think about is when we

473
00:16:37,240 --> 00:16:35,270
look at that but for an ocean baring

474
00:16:39,220 --> 00:16:37,250
planet like the Aqua planet if you

475
00:16:41,079 --> 00:16:39,230
actually do include ocean heat transport

476
00:16:43,000 --> 00:16:41,089
which is very very computationally

477
00:16:45,340 --> 00:16:43,010
expensive in 3d models that typically

478
00:16:48,220 --> 00:16:45,350
they don't do that but some work by Yang

479
00:16:50,199 --> 00:16:48,230
Hyun Jung or yang at all in 2014

480
00:16:52,449 --> 00:16:50,209
actually showed that you get a lot more

481
00:16:54,220 --> 00:16:52,459
ocean heat transport to the backside of

482
00:16:56,890 --> 00:16:54,230
the planet even in a synchronously

483
00:16:58,930 --> 00:16:56,900
rotating rotating case yeah so the

484
00:17:01,120 --> 00:16:58,940
caveats are with 1d is we can do the

485
00:17:03,100 --> 00:17:01,130
radiation much much better but you lose

486
00:17:05,559 --> 00:17:03,110
any information about the dynamics so

487
00:17:07,240 --> 00:17:05,569
really kind of need to understand both

488
00:17:08,980 --> 00:17:07,250
cases to know what's going on with the

489
00:17:15,460 --> 00:17:08,990
planet yeah but we are working towards

490
00:17:20,990 --> 00:17:19,700
hi so I just wanted to go back to when

491
00:17:24,080 --> 00:17:21,000
you were talking about

492
00:17:26,810 --> 00:17:24,090
I'm dwarf planets / French or well I'm

493
00:17:28,820 --> 00:17:26,820
dwarf planets that preferentially have

494
00:17:32,090 --> 00:17:28,830
high methane concentrations that are

495
00:17:35,210 --> 00:17:32,100
abiotic and that like levels am I right

496
00:17:37,940 --> 00:17:35,220
in interpreting that as atmospheric loss

497
00:17:39,620 --> 00:17:37,950
processes sort of blow off other species

498
00:17:42,410 --> 00:17:39,630
and then the methane is preferentially

499
00:17:45,470 --> 00:17:42,420
left behind or that not right no that's

500
00:17:48,830 --> 00:17:45,480
a great question so but that's not

501
00:17:50,030 --> 00:17:48,840
really right methane so the the methane

502
00:17:52,850 --> 00:17:50,040
is a little bit more confusing because

503
00:17:54,890 --> 00:17:52,860
methane survives easier around an EM

504
00:17:57,350 --> 00:17:54,900
door even though it has a lot more far

505
00:17:59,900 --> 00:17:57,360
UV flux and a lot more lyman-alpha it

506
00:18:02,210 --> 00:17:59,910
still survives stronger because of the

507
00:18:05,150 --> 00:18:02,220
other processes such as ozone that

508
00:18:07,340 --> 00:18:05,160
destroy methane so it's so it's not that

509
00:18:10,100 --> 00:18:07,350
the destruction of methane directly by

510
00:18:11,270 --> 00:18:10,110
the star is much different it's that the

511
00:18:13,580 --> 00:18:11,280
destruction of methane by other

512
00:18:16,850 --> 00:18:13,590
molecules such as water and such as

513
00:18:18,470 --> 00:18:16,860
ozone is much reduced because the n UV

514
00:18:21,800 --> 00:18:18,480
absorption the near UV that's more like

515
00:18:24,500 --> 00:18:21,810
what ozone absorbs and earth Earth's

516
00:18:27,680 --> 00:18:24,510
atmosphere that UV level is actually

517
00:18:30,110 --> 00:18:27,690
much less compared to gee doors so you

518
00:18:31,790 --> 00:18:30,120
actually get longer methane lifespans

519
00:18:33,680 --> 00:18:31,800
and so even the same flux of methane

520
00:18:34,970 --> 00:18:33,690
results in just more methane building up

521
00:18:39,470 --> 00:18:34,980
in the atmosphere gotcha