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you

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[Music]

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alright that said I'm going to give you

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mixed messages because these are slides

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that I didn't prepare at all I'm giving

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giving this talk for Casey who reminded

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me that he's at a New Horizons team

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he'll be here later in the week and so

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that's fine and I'm happy to give your

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poster imagine my surprise when I open

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my emails and like oh I'm giving the

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talk okay so this is not the talk that I

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would give now I'm a co-author in the

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last one I barely know what this is

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about so I'm going to use this as a

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demonstration of some basic astronomy

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science concepts perhaps but also how

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not to prepare and get to talk this is

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ultimately I talked about some spectra

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that were required using the IRT F

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telescope facility in the specs

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instrument and I want to just talk about

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what those are and what we're doing with

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them in the near future

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and it's the main result so far has been

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to get better spectral types of the

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stars that we've observed and this is

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important for bio signatures because if

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you're going to understand the chemistry

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on a planet then you're going to need to

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know what chemical compositions that

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that planet was made out of and you're

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going to want to know what is the

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spectral type of the star which affects

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the spectrum that impinges on the planet

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and determines photochemistry

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so all these things are important

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instead of saying that I'm going to call

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this a very nerds I RTF specs I don't

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think there are enough acronyms so

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exosystem spectral characterization and

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put on a graph you can't really read

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okay alright so this is something you

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should probably not do is give a list of

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things and you can't read and especially

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to start off with the list which I think

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I should just start with the conclusions

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which is that we can type the spectral

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types of stars much better using this

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infrared spectra where you need somebody

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to help us extract chemical abundances

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from these IR spectra and we'll show

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some of those results

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but instead Casey chose to say hey we

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got some new observing time and we're

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going

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- look at these host stars of in the

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infrared a few microns emission from 16

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of the best Kepler host stars with

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planets in the terrestrial habitable

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zone we're going to be observing these

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stars in June and we're going to get

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more data like the rest of the data

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you're going to see and we want to know

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what can we expect from these

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measurements and then we're going to

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look at some of the measurements we've

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already taken okay so this is all part

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of a survey that Casey's been involved

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with culty nerds it's 50 plus nerds

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targets so it sounds like senior

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scientist doesn't it yeah we have

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observed a number of systems that have

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some sort of circumstellar material and

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the infrared from about 0.8 microns to 5

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microns spectral resolution about a

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thousand to 2,000 with some pretty good

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photometry gives us some new interesting

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windows into what these spectral types

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are like so these graphs don't don't

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look at the middle one because you know

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that you can read that's the one you

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don't want to look at is yeah this is

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ridiculous do not ever kids don't put in

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a graph just puts labels that they're

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too small to read even on my laptop I

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can't even read them on your laptop he's

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just trying to say though we can get

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data and they kind of look like this and

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okay so the first thing we need to do is

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to figure out the spectral types of

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stars you'd think we could know this you

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guys are all familiar with spectral

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types oba FG km/l T and the mnemonic

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yeah and why right so only boring

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astronomers find gratification knowing

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so these are the different spectral

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types in the spectra that you can get of

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comparable quality to the spectra that

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we've obtained in the infrared you can

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see how many features that are and you

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can use these spectral features in these

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absorption lines to type them Rainer at

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all 2009 have done this for 200 stars

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f G M and K stars hey why should it be

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FG km don't you think FG m k okay so and

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they have been able to get em basically

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characterize the Stars based on the

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equivalent widths the depths of those

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absorption features that specific ones

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and build up a library of stars and and

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we have taken these stars and the colors

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obviously is from the legend that's at

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the bottom on the next slide so we have

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disks we have stars with disk we have

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stars with circumstellar material that

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seems to have followed a giant impact we

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have disk that of a planet observing the

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system or just hot dust anyway there are

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these different types of systems all

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with different circumstances

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okay we can characterize these obviously

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you need all this other information as

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okay so here are some representative

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spectra that we've taken so here's

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here's the important thing you need to

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ignore this graph you need to look at

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this one first so the first thing we do

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is we need to characterize the depth of

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the absorption features in particular

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wavelength and to know the depth of an

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absorption feature of course you want to

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know how much is that particular atomic

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transition absorbing out of the

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continuum starlight and to do that you

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need to know the continuum starlight and

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it's a real challenge in the infrared

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because there are so many spectral

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features that it's very hard to even fit

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a continuum and so you have to use

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smoothing of a spectrum to get a

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continuum like this then you can start

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to look at specific absorption features

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and get the depth of those features and

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now these are six atomic lines these two

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are magnesium these two are sodium and

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these are the depth of the absorption

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the equivalent widths as a function of

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the spectral type which is mostly just

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temperature here which is basically : K

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or M or whatever as a function of

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temperature but it turns out it's

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different if you're talking about a K

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star on the main sequence or if you're

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talking about a K star that is a giant

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star and so these red curves are showing

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what that library from Rainer at all

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2009 says are the equivalent widths if

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you're talking about K dwarfs G dwarfs

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etc and the blue and green lines are

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what those equivalents would be if

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you're talking about K Giants and so by

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looking at the equivalent width in a

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spectrum matching them to spectral types

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you can get some information about

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whether you're looking at a giant if it

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lines with the blue green bars here or

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red and it's important to do this in

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multiple lines because if you look at an

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equivalent with you could have it

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matching at this spectral type or this

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spectral type but it's not going to work

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that way for all of these stars and with

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with all of those lines so by looking at

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a multiple of multiplicity of lines you

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can get exact spectral types

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so it turns out that there was a star

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that type of 3 162 that was classified

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previously as a main-sequence star of a

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k4 to k7 type but instead it turns out

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to be K 2 class 3 giant and so this is

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very important that's not a star you

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would want to look for life around so

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this sort of basic work is very

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important to do and especially in the

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infrared here okay we can also look at

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emission lines that was absorption lines

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and we can look at equivalent widths of

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emission lines in a similar way and you

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can find out other information but in

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case you didn't tell me what happens

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here I'm going to skip that okay now

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another feature of the infrared is that

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you can start to look for circumstellar

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gas as well as dust and so first we want

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to talk about gas and in this wavelength

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range you have these overtones from Co

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emission and we do see this in a number

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of systems as you can read which system

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we're talking about here ok that's

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actually a reference that's ANOVA which

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is known to have Co emission and then

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this is 5100 which is a system plant

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information and it also is showing some

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CEOs or from solar got so that's

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something interesting that we can get

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out of the spectra and sometimes we see

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see own absorption as well so ha ok so

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this is 50 100 and it's showing Co a

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mission and you put that here to show

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you that we're seeing absorption of

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radiation from foreground material in

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front of some of these stars at exactly

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the wavelength that we see Co emission

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so we are seeing CEO absorption in front

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of some of these stars what does it mean

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I don't know but we're seeing it ok so

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now these are it don't you love it when

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a speaker gives up and what a pleasant

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surprise look at this slide I didn't

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know that was there ok

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this is a infrared spectra of F a F G

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and K stars and showing that a number of

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these systems show not just CEO emission

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access but actual continuum infrared

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emission excesses at four to five

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microns showing that there is dust in

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those systems that is emitting engineer

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for red and we can compare that to these

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same systems we can look at the infrared

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spectra at longer wavelengths okay and

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it turns out some of these systems have

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you can see which ones they they have

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they have cold emission in the farm Fred

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this is Spitzer data overlaid on these

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same systems with the specs data we've

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got so some of these dusty systems are

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indeed showing dust out in the Kuiper

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belt regions or in the mid infrared

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region so at one a you they emit in the

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mid infrared and you're seeing silicates

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or silica hot rock may be due to

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planetary collisions generating silica

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and then in other systems with planets

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we see Co emission and put HL tau here

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but HL tau is not in one of these and so

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let me go to the conclusions then got a

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lot of spectra from the Nerds survey

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they use the equivalent which measures

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at particular wavelengths of line to do

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better spectral typing of the stars but

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what we haven't done yet is converted

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the spectra into abundances high

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precision abundances of these species

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and whatever other things are emitting

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infrared and that would include a

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phosphorus I think so we are looking for

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people to help us do the spectral

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modeling of the spectra and in the

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infrared to get cellar abundances and I

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will stop there before I commit more

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we have time for a couple questions

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couple quick questions please I will

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text Katie okay though I should have

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practiced the talk but I was I don't

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know what I was doing

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okay thank you all right let's give our