Yasuhiro Hasegawa
SAG 23: The Impact of Exo-Zodiacal Dust on Exoplanet Direct Imaging Surveys

OK.
Great. Yeah.
So the I mean, as Yasuhiro Hasegawa from JPL, then basically you know that what's?
Where the bone.
I agree.
Yeah. Sorry about it.
Yeah. So then, yeah, again, I'm as Yasuhiro. They're from JPL that today I'd like to discuss about the effort of the SAG 23 and then the basically fidget.
This is about the impact of the.
On exoplanet imaging surveys.
Basically this know the effort started to not around June 2022.
So that's why we spend more than two years to, you know, to summarize, basically explore the literature and such, and then summarize what's the, you know, the knowledge gap and what the potential recommendation we can make. And then basically this effort will be made by the about you.
Know 40 expert of the Exosodi solar system.
Delicious disk in general.
So that's why this is really the community effort. And then I I'm starting here in front of you right now. But then this again this is.
The really the community effort and then just like to summarize it, summarize it and then basically call it here.
Is that another John from the STS?
Yeah. Isa from ESA and then the myself from JPL.
Right. So then what's take the loading?
So then basically now, as you know, solar system are composed of the the planet and small bodies and also the tiny dust particles. And then this is of course the one of the famous example solar system. And as you can see here the sun and then there are.
A bunch of the planet. And then there are lots of them.
The small bodies which is shown by the green door black dot and then but at the same time important resolar system is also full of the the small dust particle and then.
Especially here, the kind of hot dust and the warm dust and the cold dust. And then that these two component, I mean a hot and warm these are called exosodi.
Acal, I couldn't say that.
Exodia, dust and Exosodon showed so that time keep saying the exhaust, but anyway. So then the basically the room does is literally located in habitable zone, so that's why you know the. Basically you know that you know we can detect them in the summary mission, which is about.
10 Micron.
If you focus on other hotels, sorry hotels which is close to the central station.
So that's when the emission thermal emission is basically peak around another one Micron and then the these are basically another focus on.
And then what?
Why do we care?
So basically the you know, basically you know that exhaust provide another Rd. source, you know noise or confusion sources for if you like to detect and the habitable planet by directly using a method, for example the.
Especially for the warm zodi again, it's become the the noise or confusion sources by the scattered light in our visible. And then this is the one example done by the crystal and his group. And then as you can see, basically the Y axis is the yield estimate as.
A function of the median zodi levels and then as you can see, if the zodi level is increasing, the yield is decreasing.
So that's why the Exodus is really the one key parameter to affect on the yield estimates. So.
We need to better understand the exodus. Still, we don't.
What's the hotosho hotos?
But then they know that we recently know that they know probably the presence of the hoto the introduced a chronographic leaking.
So that's why again, it's really tricky to do varsity detector habitable planet.
OK.
So then the actual this kind of risk is already known are more than decays and it's interesting that in the one of the report is made no 1998.
So basically, you know that we have a more than 20 years old recommendations and then another interesting fact is that in the first.
SAC sub.
Was also focused on Exodus stuff, which was done about 10 years ago, and then the basically this recommendation of finding suggest that we should know the occurrence rate of the exodus better using the some telescope like L B TI.
And also that we should use the old observational resources to develop the know better or reliable target selection strategies and also that we have to understand the origin of the solar system to develop in the complete understanding and then the and then again that this kind of study.
Is already done about more than 10 years ago, so that's why we decide to rebuild this kind of key issues.
And then these are the list of the focus area of the.
Area of the SAT, 23 and then basically we try to focus on the.
For the wide range, from the theory to the observation, and then even including the recommendation to the accept gap list.
Now again, this is done by the mother about 46 part and so this is meant to be a real committee effort.
All right. So then the basically I'd like to start from the one of the key result for the exodif, which is coming from the host survey done by the L B TIS and then basically that this survey not try to characterize or try to estimate occur.
Rate of the rooms or the?
Yeah, Azure.
So you can see.
So basically that on left hand right hand side you know you can see that the detection rate as a function of stereotype and then if you focus on a population which includes all the stars, clearly that occurrence rate of the is about 20 or 40% of the.
Main sequence star. So that's why it's really common that we could neglect it and then also that if you look at the red bar, which is the showing the correlation with the.
Cord of debris so, so and then this is a good in a sense that we can put a constraint origin of the warmth or the right.
So that career, if you detect a code of code, ask them.
We have a high chance to detect out worms OD as well, and then so these are kind of little bit negative result for the direct imaging community but in the positive result is that they are showing right. Sorry on the left. Sorry on the right on your side.
That's a basic know that this is this is showing that the fraction of the star of the function, the Audi level no normalize normalized by the thoracic of those and.
Inside the base gate showed accumulated fraction as a function of the Zodiac level and then black with the best fit, and then blue is about Sigma and then as you can see, basically the majority of Sunrise Star has the level and then you know basically best fit is.
About 3 three Zodiac level and then this is the really great. I mean because the zodi level is really low.
So that's like kind of promising.
And then so that's why some people say, hey, yeah, maybe that we can retire like Zodiac at all and the entire. But in our finding that finding suggest that it's not so now from here I'd like to summarize some kind of knowledge gap.
You know, we find out and then after that, we'd like to summarize, summarize a key step we'd like to recommend.
First things is that you know the the scattered right.
So the base scanner that is really great, but in the base case they are detecting the warm the summer emission so so this means that you know the but in that for the HW we are looking at the we are looking at the scattered light now visible so.
That's why we have to know that what's scattering the property of the and then the JWT is another good example to characterize in a summary mission from the Zodiac, which is really great.
But then if you look at the.
The visible observation, which is done by that HST, then basically that the currently not working ongoing is quite huge and then all the nodes, all these within a in a working group.
So that's why still we couldn't directly compare the know the rooms, the family mission and also the scapularide from the rooms OD.
So this is the knowledge gap one and then two is that the presence of the hot task.
And then again, still we don't know what the detailed property of hot task, but in the one of the optical room baseline.
Suggest that the presence of the hot Saudi also tend to be common.
So again that they know the Y axis on the left side, Y axis show the excess frequency of the functions.
A stereotype. And if you look at the blue one or the star is included and then as you can see about 20% of the main sequence star has the and then actually the typically not typical. You know the flags coming from the hotel days above the one.
Percent.
Of the Stella flags, which is really a significant.
That's why, again, we could neglect it.
And then that then actually decentral JWST observation showed that the sum of the might be located really close to the edge of the inner working angle which create a chronographic rigid.
So that's removing the hotsoday effect is also tricky, and another thing is that again, that if you like to observe the habitable planet by the HW, we are going to focus on the optical, then the for the thermal emission which is shown the top left.
Top. Sorry. Top right then that you know the auction or the summary mission is not so sensitive to the dash grain, but in the scattering properties super sensitive, which is shown up below.
And they each line they put in a corresponding to the different size of the grains.
So that's why that we have to understand another hot dust property better.
And then the last one is that the, you know, the poorly constrained origin, they're still not.
As I as we discussed basically you know there are some kind of correlation between the warm and cold dust so that so we have some idea of the how we can deliver the warm debris from the cold dust.
So then main idea is that another.
Maybe that I know that some small grains created in other quarter belt and then maybe transferred to the inner the inward by the maybe the PR drag or interaction with the planet. Or that maybe EXO comment might be scattered invalid by the planet. Or maybe another dynamical process?
A nice understanding, but in the if they know that the presence is really sensitive to the planetary system architecture, then that's this means that we have to, we have to do the much more complete on the parameter study to which planetary system is a good target for the.
Hwo and then the for the for the actual situations?
And the main reason that the HOTOS which is basically close located across the central star.
So that's why does suffering from the sublimation and then once the dust is sublimated and the sides become smaller then basically you know that radiation pressure comes in.
So that's why the.
Maybe that the dust particle move from the cord of debris to the warm debris, and then maybe even migrate to the hot debris.
But then, if the evaporation taking place, these guys know that the blow away by the radiation pressure.
So that's when the steel and then no one have done that kind of such a computer study. And then if that kind of thing's happening, then we don't know how widely observed the system has Audi, right, so.
If that you know the radiation pressure kicked out, then then maybe that in a lifetime is short, but still we get.
We are observation results suggest that the hotels tend to be common, so that's why there are lots of unknown going on.
So that's why still the theoretical study will be needed to have better understanding.
So that's why I know that.
Now I like to move to some kind of key steps we identify and then particularly that if we like to, you know, fill out the gap especially about the, then definitely we like to better characterize them.
And then basically we have them on the precast observation chapter, which summarize the order detail.
But what kind of observation we needed?
And then here I just.
Briefly summarize the two parts.
One is the I think it's really ideal to complete that L B TIBTI whole service and then because of the funding limitation, roughly half the target was absorbed.
But then if you include, know that if you try to complete a tab as originally plan basically that the constraint could be improved by a factor of three, and also that you know that now Roman or Space Telescope will be flying in a couple of years and then.
Roman Space Telescope of the CGI and the chronograph instrument and then CGI basically observed on the right in the visible.
So that's why we can directly compare.
The summary mission, the scattered property.
So that's why these two be one of the most important things we should do at the Community effort.
There's an endorphin that gap to against a better to characterize hot task.
And then yeah, for that is of course the temperature is high.
So that's why we have to focus on more like infrared optical regime and then it seems that in the Matis, which is kind of second instrument, you know that as a part of the VFTI and then which is the basically the spectral interferometer observation and.
Then this kind of observation basically gives us the.
Opportunity to characterize geometry and also the spectral features.
And then also that the not which is another instrument will be mount to the L B TLBTI that basically we can characterize the occurrence rate much better.
Right. And then the gap three, so the this is more like a theoretical study, so again that.
This basically precursor theoretical chapters.
Also, the radio transfer chapters summarize the detail, but then it's, you know, we should do a much more complete **** study, including the all the various delivering mechanisms and also that it's really critical to develop the endo to end.
By taking into account a detailed *** properties and also the radio transmission relation.
So the finally the this is a kind of summary what we have done so far basically about one years ago we did a one day sub one day workshop in order to get to get more input from the communities and then about 7:00-ish people attended including the.
Public talk from the communities.
And then we had a really nice discussion and also that for the documentation, basically, you know the whole DOC review will be already submitted apsp and it should be accepted soon. And then also we are going to.
They'll send some document to the accept group about the gap list, and then finally that you know the final report will be available in a in a couple months from now. So and then that document will be available to the community at no cost.
So that's why being more than welcome to check the detail and then thank you so much.
We have time for one quick question.
Can you just comment a little bit further comparing and contrasting further lbti observations versus Roman chronograph observations?
One do it all.
Is one much better than the other?
Do you need to do both?
Just elaborate a bit on that. I I think that's a really good question.
And then that that, you know, of course, ideally we like to do both, right.
So then, because of the L B TI-1, basically we can get the better occurrence rate and then the more the cornea Graf, we can characterize the spectral spectral property.
But then if we choose, you know the, you know, still, I guess I'd like to discuss with the Member, but then that my impression is that maybe that the CGI observation might be more promising in a sense that.
We can do the direct to comparison between the scaled properties and the sample properties.
So then if we focus on low xority level target and then try to see what's the like, some kind of current understanding of that properties use, you know that it's valid enough to extrapolate the scattering property.
So. So that's the kind of my guess, but then I'm happy to discuss more with the the expert.
Great. Thank you so much. Thank you.