Exoplanets with JWST: How one telescope revolutionized a field in about 100 Days

thank you foreign thank you today's speaker Mercedes Lopez Morales grew up on Tenerife which is one of the Canary Islands right which is a part of Spain yes and she did her undergraduate studies at the University of La Laguna famous university and the canaries from there she came to the U.S for her Graduate Studies at the University of North Carolina in Chapel Hill and she first visited CFA for a week in 2003. a year before finishing her PhD right I remember that week well and she came to learn how to use Todd core and Willie Taurus showed her how to use Todd core and she went off and applied that new precious new knowledge to uh an analysis of gu booties and put out a paper that received quite a bit of attention for a paper and a double-line eclipsing binary and that signaled her interest in deriving fundamental Stellar parameters from observations which she did for a number of years and after six post-doc years in Washington DC at the department of terrestrial magnetism first is a NASA astrobiology researcher and then as a Hubble fellow she returned to Spain for a couple of years that's right and ten years ago we managed to convince her to come to see Sao and join the harps North collaboration because we had access to 80 nights per year on the Italian 3.6 meter telescopio Galileo nazianale and while some of us endured the long trip to the canaries to observe on Harps North at the Rock De Los Muchachos Observatory uh Mercedes didn't seem to mind a layover in Tenerife and with great foresight Mercedes evolved an interest in the study of exoplanet atmospheres for example proposing the detection of molecular molecular oxygen with future facilities such as the giant Magellan telescope and she had a very large program on HST for a transmission spectroscopy and that has positioned her well for the revolution in the spectroscopy of exoplanet atmospheres enabled by jwst which is the topic of today's colloquium thank you Dave for the introduction and all here in particular to the colloquium me to give this presentation which I was just telling Jonas Jonathan mcgole who gives a talk next week that is really weird to be given the colloquium in your home institution but so as Dave was saying you know and most of you know you know I work on exoplanets um you know all the way from Jupiters to like earth-sized planets with a particular soft spot for detecting and characterizing their atmospheres um but uh before I start showing you any of that I wanted to introduce to you the exoplan atmospheres group at Sao or CFA because I realized that with about two plus years of pandemic and you know a lot of people coming and going we probably don't know everybody's faces anymore and this is a good way to you know showcase the people who are here working on this kind of stuff and also working already the velocity Mass measurements and you know if you see them around you can say hello and you know ask them what you're doing and you know I'm so proud of working with these people that you know most of the work that you're gonna see here you know it's always saying to everybody not just me and we have a position opening so I figured that I could advertise that as well um so going back to the actual talk I mean I see a few people in the audience who are actually exoplaning experts please bear with me for the first like 10 to 15 minutes because you know I need to bring everybody up to speed especially the younger people who don't work in the field but I promise to you that if you stay awake after the first 15 minutes you're gonna see really cool stuff so please bear with me so you know as most of you know as all of us know we only knew of a few planets for centuries and even during the 20th century up to 1995 we still only knew of the planets in the solar system and that was it but about three decades ago things started to change because we started we discovered the first exoplanet around another star and after that with a number of techniques that are shown here in different colors we have discovered to date about 23 000 candidates and of those over 5000 are confirmed exoplanets so this has been crazy however if you see the distribution of planets that we have here you see that we have a lot of things we have Jupiter Saturn subniptions we don't have any Uranus yet and we have some rocky planets but they're still not quite like Venus on Earth or Mercury or Mars where those are the rocky planets around msworths which I will show you something about that at the very end of the talk but you know the base at which we are discovering planets is now slowing down anytime soon uh you know with existing missions such as stairs and Gaia and upcoming missions such as the Nancy Roman Space Telescope and also a bunch of instrumentation from the ground you know the new elt is coming and a very sophisticated instrumentation in those new elts the expectation is that if the pace of Discovery continues by 2030 we will have about 85 000 candidate exoplanets and even if only 15 to 20 of those get confirmed we would have about 15 000 confirmed planets to look at and now if you look at here now we will have by the end of this uh decade hopefully we will have things like Venus and Mars and we are still will not be sensitive to things like Mercury and Mars so the chase will continue right so you know a portion of the exoplane community that's what they do you know they try to find more planets going all the way down to the bottom to the smallest possible Mass or radius but in the meantime a fraction of us have gotten interested in the atmospheres of the planets we actually want to know what the physical and chemical parameters of these planets are and with that information we want to be able to answer some questions that have been lingering about for decades if not more one of those questions is how planets form and evolve that's one of those questions another question is how what are these planets made of and you know what the different planets look like when you actually look at their Spectrum and another question is how diverse are exoplanets right especially like you know what physical and chemical property parameter space they cover and especially in particular how do the solar system planets actually compare to this extrasolar beasts right so I dare to say and I already said this when I gave the IDC launch a few months ago I dare to say that exoplanets is now at the stage the Stellar astrophysics was pretty much 100 years ago when Cecilia Payne finally figured out you know what this all these crazy lines in the spectrum of stars look like and she started to tag those lines to chemical elements that's where we are with exoplanets and by finding the chemical composition of atmospheres of exoplanets which is what we are trying to do using similar techniques to what they were using 100 years ago we can answer the first the previous questions that I was asking about so this is how we do it again for those of you in the audience who work at a supplantis please bear with me but for those of you who don't This legal explanation is gonna give you what you need to understand the Spectra that I'm going to show you later okay so so we basically have two main techniques to study exoplanary atmospheres one of them is Select imagine that one is easy to imagine you know you block the light coming from the star with a coronograph or something you find a little planet you put a slit on it and you get a spectrum and voila there is a spectrum of the planet and you can look at it however this technique is a little bit behind because our technology is not quite there yet we can do Jupiter's young Jupiters but basically nothing else so what we are doing now is using this other technique which uses transit in exoplanets to do that science to look at the atmospheres of the planets and what this technique does as some of you know is we we take advantage of the geometry of the system and we look at the ones that happen to pass in front and behind the star every so often when the planet goes in front of the star we look at the light that percolates through the atmosphere of the planet when the planet goes behind the star we look at the light that is lost from the system and we also have this other technique which I'm not going to show you yet because those results are not out yet but we have these other techniques where we follow the planet along you know along the orbit and we can do like these face Maps where we see light coming from the planet at different angles so this is basically how we are doing it and this again if you don't work on this I understand that this is a little bit conceptually sort of the convoluted but just so you know so you understand what you're going to be looking at later so basically the way we do it is we point the telescope at the you know the star when the planet is transiting and we monitor it you know we take Spectra continuously while before the planet goes in front of it while the planet is in front of it and after the planet is in front of it and what we do is then we take that Spectra we bend it in different colors and we plot the Liker of the different colors of light and this is like a stellar astrophysics again right so everybody too again you know their cellular astrophysics class you know the the you know the like like everybody learn about the idea of opacity this is exactly the same different chemicals gives you a different opacity right in the atmosphere of the planet so basically what happens here is that when you hit a wavelength when you hit a color where some element is absorbing the opacity of the atmosphere of the planet changes so the planet looks bigger so what we do is we look at the different colors of the light and we look uh versus um How deep the transit is at the different colors and that gives you an idea of what elements are in there because the size of the planet changes if it is observed if that element is there and the light is being absorbed for the element so this is our Spectra notice that this is where people get super confused notice that our Spectra are upside down right so those bumps that you see going up that's absorption in a stellar Spectrum so anytime that you see a bump going up that is absorption by an element and this is you know as you can see the technique is not super complicated it's fairly basic the problem is the Precision that you need so this changes in the size of the planet that we are talking about if you have a Jupiter sized planet around an mdorf for example those changes in the size of the planet are the of the earth there's 10 to the minus three if you have a planet a Jupiter size planetary dwarf that's of yours there's 10 to the minus four if you have a terrestrial planet around an M dwarf those changes are of the order simply -5 and I run a G dwarf those changes are of the orders 10 to the minus 6. so this is almost like nanotechnology going over here so quite there yet but as you can see like you know that's why this is complicated because we need to push the uh instrumentation to the Limit of what they can do and this is basically what we have been doing for the past 20 years you know we have been using instrumentation available mostly the hardware Space Telescope Spitzer and the Magellan telescopes in Chile among other ground-based telescopes to actually try to look to find these little changes in the in the depth of the transit as a function of color and this figure that I show you here that kind of tries to represent you know the classic spectral type diagram from Stars this is the first attempt to do something like that with exoplanets this figure more or less summarizes what we have been able to do up to last year uh so far we have been able to observe with existing instrumentation about 60 extra solar planets the atmosphere of about 60. here you only have 10 but it kind of shows you the idea of like you know everything that we have been able to do has been from about 0.3 microns to 1.7 microns so that's Optical I'm very near infrared uh we have been able to do a spectroscopy with that mostly with Hubble but also from the ground and then as Pizza has provided two points one 3.6 microns and another one at five microns that we have tried to use you know to Anchor the spectrum of these planets so basically we we had hit the limit last year this is basically how well we could do and we had learned a number of things but I would say not enough one thing that we have learned is that about only about seven percent of the planets have clear atmospheres everything else clouds were getting in our way and we weren't able to see much there are some features that we have been able to detect for example you see that like this feature here 1.4 microns that's water so you see that we have been able to detect water in pretty much every planet that didn't have a lot of clouds and let us see through a little bit so water seems to be plenty out there you know these are all Jupiters by the way so we we have been able to detect potassium potassium and sodium but there is something going on there's some some of the planets show potassium some of them sodium they don't seem to boss a show at the same time so something is going on there that we couldn't really understand and um another thing that you see from this diagram is this is meant to be from the top to the bottom is meant to be cloudy like a cloudiness index like the planet at the very top it was very clear the planet at the very bottom is very cloudy we don't have a clue of what causes this physical properties in the planets you know we have looked at everything all kind of parameters like you know supplantic temperature uh distance from the study radiation all kind of stuff and we haven't been able to find a correlation so we were pretty much lost and another thing that we have been limited up to last year is that we couldn't we could see water and some you know Elemental abundancies well some elements like sodium and potassium but we didn't have enough inspector coverage to see anything else in particular things like carbon molecules and that's super important because as I will show you later carbon is one of the critical things to be able to understand how this plan is formed so that's where we were last year everything changed when the jwc launched successfully on December 21st uh like Christmas Day 2021 and ever since I'm going to show you from now on is jwc results um literally 48 Hours of jwst observations so you get an idea of how things have changed right just just from the fact of having put this telescope up into space and having it work very nicely this is what Hubble could do and remember that this is a logarithmic scale down here so this is what Hubble could do it could do you know ultraviolet to the near infrared this is what gwc can do now it can bring us all the way out to 30 microns and it has four different instruments that you see here and they covered you know like almost of a spectroscopy direct Imaging and so on so this one itself combined with the fact that the aperture of jwst is about seven times larger than the aperture of HST is part of the reason why all this ground breaking results are happening now another thing that you might not realize and this is why at the beginning of my talk I say like you know the telescope that changed exoplan is in 100 years uh sorry in 100 days is that to this day right now there is about 10 well and this happened even before the Telescope launched about 10 000 hours has been already scheduled for programs across the board with jwst and this was part of early release science programs um guarantee time observations for people who have been working on the on the telescope and then the first open call for proposals that was cycle one so we had already um 10 000 hours schedule of which 25 of the time was dedicated to programs that are going to be of surf exoplanets and there is about this this diagram here shows the size versus equilibrium temperature of all the planets that are ready have a scheduled observations on jwst so there's about 60 points there that's as many as we had managed to actually observe an atmosphere of over the past 20 years and all these observations had to happen by the end of this year maybe some of them will spill over into 2024 a little bit but this is a stuff that we're gonna have in Hand by the end of this year just to give you an idea of what's Happening um right now I just because of the duration of the talk as well and also because of what has come out I'm going to focus the rest of the presentation in these two planets that I highlight here with the green circles one of them is the one at the top is a Jupiter with a temperature of about a thousand Kelvin that's was 39 that's part of the early release science program and this other one here is uh the first observation of the atmosphere of a terrestrial planet like this planet has exactly one Earth radius and a temperature of about 600 Kelvin which is just a little bit cooler than Venus so this is what I'm going to show you um in the remaining of the talk so first let's go with the Jupiter size planet was 39 so as you see here West 39 is a Jupiter size planets large like slightly larger than Jupiter but actually has the mass of Saturn so n is about seven times hotter than Jupiter it has a temperature of about a thousand Kelvin so this thing is fairly puffy and these observations that you see here this is probably the best observations that we had from the ground I'm sorry before jwc both from the ground and with HST and you see here that on this planet in particular we could stick we could already see clearly some things like water bands we could see sodium and we could see a tiny hint of potassium and that's all we had and with this data we could already we could already tell you some things for example we could tell you what the metallicity of the planet was right and that metallicity when you plot it in a mass metallicity diagram and you compare it to for example the planets in our own solar system you see that this this particular object appear to be to have a metallicity that was like a factor of 10 to 20 times higher than the metallicity of Saturn and Jupiter so at the time this was published um three years ago the last one at the time we were saying that there was something really odd about exoplanets you know we were saying that some different formation mechanisms must be happening around this with with these Jupiters because their metallicity doesn't look like the metallicity of the gas giants in the solar system so that's where we were but we couldn't tell anything else because as you see we couldn't do any other molecules so um this was precisely why this target was selected for the early release um science program for those of you not familiar with jwst at the very beginning this was uh this was about five years ago um a space telescope and NASA this was at the time when jwc was meant to last five years 10 years if we were lucky so everybody was scrambling and saying we really need to give data like really really early so people can figure out how to use the telescope because if it you know if it is as slow as everything else so far we are going to run out of telescope before people figure out how to use the data so they gave um I think it was like 500 hours to I think it was 13 different early release science programs or not you know on a wide range of topics from planetary science to cosmology and we were awarded this particular um program on transiting planets uh for which they gave us 78 hours of telescope time and basically what we argued in this program was that we needed to be able to use all the possible modes or as many modes as possible on the telescope to figure out which ones work for exoplanets and which ones didn't because otherwise we will we will be wasting our time when applying for telescope time we wanted to test um how long could the telescope actually follow at Target and you know the the data to be precise enough so that was the second program that you see here for a face curve and we also wanted to test um how precise could we get because the numbers on paper said that the telescope the the objective call or something like that was 30 parts per million Precision if that was through you know terrestrial planets were hopeless so we better start to build something else already so um so these programs you know in addition to doing a little bit of science with exoplanets we're actually meant to test that and they were meant to also like uh uh uh produce pipelines and you know information for the community so they could quickly jump into exoplanet data and you know start producing science with it so um between July so what I'm going to show you here is is the first project the one in which we had to test the different instruments um the the other data sets we have them in hand but they're not ready to publish it and so so basically uh for what's 39 between July 10th and July 30 we got four different transits on each one of these instrument modes that you see here near the spec prism going from 0.5 to 5.3 micros near cam with this filter that gives you data between 2.4 and 4 microns near resource that gives you data between about 0.6 and 2.8 microns and near spec with this 395 age reason which gives you data between 2.8 and 5.3 microns but this one is a higher resolution it's about a resolution of about three thousand these are the data I realized that you cannot read the labels but I had to find a way to actually show you the whole thing in one place these are the data from the four different instruments um and uh you see a lot of Wiggles in there so there is signal in there and just to give you um a little bit of insight of what those Wiggles are and actually this is what I'm going to be focusing on uh you see that we have found potassium water pretty much all the water vans that are available we have found sodium we have found carbon dioxide and we have found sulfur dioxide um so so I'm going to go now into oh and uh there is already six accepted nature papers on this um observations and what I'm going to show you here is basically based on information that has been published in these papers so let's go with the first detection um this is a portion of the prism data that goes between about 2.8 microns and 5.3 microns and what you see here the discovery here that you probably saw it announced a few a couple months ago is that well first of all we detect water we detect water clearly on this band and many other bands with with uh you know significant levels larger than 20 percent previously with HST if we hit five percent we were jumping like we were so happy so now we're just beating like hitting 20 easily with water carbon dioxide we actually get like 30 Sigma detections of carbon dioxide and this was like you just have to look at the data and it was there so why are these two um detections of water and carbon dioxide so important well so let me see um remember that I was telling you about plant information right so there's a theory by carrying over that basically tells you that if the planets form like gas giant plant is formed beyond the water line or beyond the ice lines they should be enriched in these heavy elements right and in particular they their carbon dioxide their carbon to oxygen ratio should be different than the carbon II oxygen ratio from the whole star and what we find in this case is that the carbon II oxygen ratio based on that water and CO2 detection is between 0.3 and 0.46 the carbon II oxygen ratio of the hose of the whole star is 0.58 so in this case the carbon II oxygen ratio is lower that means that the atmosphere of the planet has a lot more oxygen than the atmosphere of the star itself and also and also more oxygen than carbon that's already telling us something another thing that we can discard from the data very very clearly is that the carbon II oxygen ratio is no larger than one and that also has implications from where this planet form basically means that it couldn't form further out in the disk where carbon is abundant so in this case you would have more carbon than oxygen so basically just with these observations for the first time I would say we can definitely say that these planets must have formed between the water line and the CO2 line so we basically can place like a very strong limit to where the planet form and somehow this planet has migrated in and that's another thing that we know now that is true so that comes from the second detection never seen before like this we detect potassium we detect potassium super clearly potassium has been a sneaky one because if you try to observe it from the ground you overlaps with the molecular oxygen band from our our own atmosphere so you can't pull it out really and with a hub of observations the resolution is not large enough so potassium sometimes you say sometimes you don't so you don't know if it is that the planet doesn't have it or the resolution of your data doesn't allow for it but here there is a very clear detection of potassium and this is with the nearest data which has a resolution of about 700 so here you see very clear detection of potassium 6.6.8 Sigma and not only that but just the fact that the nearest data also covers some water bands allows us to detect the potassium to oxygen ratio in this particular planet and what we find is that that ratio is super solar that means that the planet has more potassium than the star and what does that mean I mean and this is like as timely as it gets right so somebody a few months ago published a paper that basically said that if God's giant planets migrate these planets should be you know first of all they should be reaching water because they come from Far further out but they also should be rich in refractory Elements which are sodium and potassium because they will be accreting those as they migrate in because those elements are stuck in like tiny little rocks or whatever in the way in so if the planet is migrating they it should be rich in potassium and the co ratio should be larger than the star and that's exactly what we find if you see these models here basically uh the car the potassium to oxygen ratio is between 0.2 and 0.4 which is one to three times solar and um that prediction that's like I just went a little bit too fast but that prediction basically let me go back for a second that prediction totally puts a picture of like how this thing formed together because on one hand we see that the co ratio is less than the star that means that the planet must have formed somewhere between the Water Ice Line the CO2 Ice Line and then the potassium to oxygen ratio is actually larger than the star so that means that our planet came in slowly but surely it came in so now we know that this planet actually forms somewhere else and another thing that we knew that I forgot to mention before is that the uh the um the metallicity of the planet is about 10 times smaller it's not the 150 metallicity that we were seeing with the HST data at all it turns out that it is 10 times taller and I will show you that to you in a little bit and explain why that is important as well the third result and again this is from the same data set that's the result that I wanted to highlight is this mystery molecule that we found and this was a little bit of a headache but at the same time it was super fun to do so you know I go back to the same Spectrum where I show you the water and the CO2 initially and you can see here there's a little bump in that region then local thermodynamic all equilibrium models cannot fit that bump so the theorists the modelers in the uh early release science team group you know were scratching their hands and say what's going on what's going on what's going on we have no idea what's going on and actually I need to give a shout out to the high Trend team here at Sao and especially you know their their high temp line list because that line list combined with people that have photochemical models actually figure out like what is that bump in there and it is sulfur dioxide this one truly took us by surprise and I will explain why next but first I will show you here um the results of this modeling for sulfur dioxide so these are actually now like non-equilibrium photochemical models and as you see here they we use um different solar metallicity models and you see that here very clearly a 10 solar metallicity model fits the data really well and what is important not only the fact that we discover sulfur dioxide what is important is that we also discover that is a very sensitive indicator of exoplanet atmosphere metallicity because as you see here before we have been using water we have been using CO2 and as you see here the three different models basically give you fits that are more or less equally good when you look at the SO2 clearly the 10 times solar metallicity model is the one that fits the data so we have found a much better metallicity indicator but again why SO2 is actually so exciting for us it's because of photochemistry I mean this thing that you're seeing here the little bump is the first detection of photochemistry in an exoplanet and photochemistry you know it's important because you know it tells you about atmospheric composition and so on on on planets like Earth it actually tells you about habitability right for example photochemistry is responsible for the from for the formation of the ozone layer on Earth you know and that's where we're here because you know oxygen gets up there ultraviolet photons dissociate the oxygen the oxygen individual oxygens go and group back you know in themes of three as ozone and that's what protects us from the ultraviolet radiation from the Sun so photochemistry in the case of a gas giant is a different process you know in the case of at terrestrial planets you know SO2 is pretty much uh ubiquitous like because you see it on Earth you see it on Venus you see it on iO and that has to do with volcanism but when you actually go to a gas giant the process is totally different what we think is happening here is that you know in normal conditions if if the planet wasn't irradiated any sulfur on the planet would be on uh you know hydrogen sulfide but the ultraviolet radiation coming from the star actually is associating the water and is creating you know oh and H that actually react with with the hydrogen sulfide and somehow any sulfur that gets left out combines to form uh sulfur dioxide so this is this is the overall reaction that you see here and this is great because it basically means that we have discovered like photochemistry in exoplanets it seems to be everywhere and you know that is promising for a field where we weren't even looking for this kind of stuff um so now you know I've shown you things that we have found now I'm going to show you something that we didn't find which hopefully you also find interesting there is no methane we can't find methane anywhere and that's actually it's a bad thing and it's a good thing right it's a bad thing because um it's exciting to find methane right but it's a good thing because it's actually telling us a lot about what's going on with these planets so this is a little bit busy um disposal a little bit busy but I'm gonna try to explain to you what we are seeing here so the points are the data and then the different lines with the different um you know intensities of pink are telling you you know in this case we fix the carbon two oxygen ratio of the star sorry of the planet and we change the metal the metallicity of the planet and in this case we do the opposite right we fix the metallicity to 10 times solar which is what we are finding from other things and then we change the carbon to oxygen ratio and you you're probably wondering Mercedes those models don't fit and that's the point right to say so there is no methane and actually the combined information between you don't have methane but you actually have a very strong CO2 band it's definitely telling you that the atmosphere is metal Rich because if you didn't have things like oxygen but you still had carbon all the carbon will combine with hydrogen but in this case we have a lot of oxygen around so you get a lot of CO2 CO2 instead of methane so that's one key piece of information and another key piece of information is that you know in this case none of the models actually fit and um so what we conclude from this particular fitting here is that our inability of simultaneously feed the methane and the CO2 in this particular case is because we're weren't including clouds in the model so this planet which initially from the Hubble data we were saying you know what this planet doesn't have any clouds we see all these features it actually does have clouds and once you include the clouds it's hard to see that gray model then everything fits so methane even though we don't say it it's actually telling a lot of the story here and he actually explains there is this big question from Hubble data for cooler planets it actually explains why we're not seeing methane in cooler planets with Hubble data because there should be a signal at 1.4 microns so we are not seeing it maybe the answer is that all these things don't form in situ they form further out and they are all metal rich like the planets in the Solar System so we might have you know this is only with one data point but we might have found why we cannot find methane so just to summarize quickly this part of the talk um this is what we have learned so far with just 39 hours of data with jwst we are detecting new new species that we had never seen before like CO2 and sulfur dioxide for the first time we're providing very strong constraints on carbon to oxygen and for example potassium to oxygen ratios which are actually consistent with migration and formation scenarios so we Are We Now can tell you where this planet form and how we migrated for the first time we have found a way to measure the metallicity of these planets um like high confidence and that's now we know that if the CO2 and the water don't do it we need to find we need we need to look for sulfur dioxide and that will provide um very high constraints from the on the metallicity in this particular case the information from the metallicity is crucial because you can place constrain of for example like core accre Christian models so what this means with the metallicity of this planet means is actually that this thing formed by core accretion no gravitational collapse of the disk because if it was gravitational collapse the composition of the planet and the atmosphere will be similar but they are not so core accretion is the one that allows for the heavier things to collapse first and then the planet to accreta gas envelope and this is what is happening in this case and also it tells you that the composition of Jupiter and Saturn are consistent with this kind of planets so maybe they all form the same way and also the first evidence of um uh photochemistry in an exoplanet which you know is promising for the for the detection of life in the future in other in other planets so quickly I wanna I wanted to give you uh before I move to the terrestrial planet you know I wanted to give you two hands in here this is actually the data from the four um instruments combined so you know it looks beautiful and one takeaway from this that I want to give to you is that the the instruments are working so well I mean it is the data are superb and all the instruments are actually giving results that are fully consistent one with with another with another so basically like every single instrument that we have tested on jwst can do extra Planet science easily the second thing is that all the results that I've shown you before like up to now they don't even involve a lot of modeling these are also for forward models but the modelers in the ERS team are now like working pretty hard on doing all the modeling like proper uh retrieval models uh to show like a full picture of what the planet is made of even give you different abundances of different molecules and so on but I'm not gonna go into that you should go to Ryan McDonald's ITC colloquium on Thursday because he's going to show you all this stuff so if you're interested go to Ryan's colloquium on Thursday at 11. so okay quickly now because I know that some of you have been waiting for this one so let's move now this is the last part of the talk let's move to to the actual uh the rest of your planet that we have down here um this planet is called LHS 475b which probably means nothing to most people um it is a exactly one is radius planet and uh it orbits an M dwarf which is about 30 the mass of the sun and uh it is at a distance of 12 parsecs this project is not part of the Year observations it's actually a separate project and basically you see here like all the members of the team for that particular project um and this is submitted to nature but nature basically has waived All rights and we can show this stuff everywhere and it was actually presented at the double as and there was a press release about this um two weeks ago so why is the science so important well for those of you following this kind of science you know that we are trying to find Earth-like planets and with the current technology that we have right now we don't we can't get yet to an Earth-like planet around uh you know like a sunlight star so for years people have been talking about this alternative of like looking for earth size planets around M doors because those are closer they're smaller so technically it is feasible to observe those planets but now the big elephant in the room has always been like okay well you know m d words are like pretty active you know like they give off this huge UV and x-ray flares so you know like the the atmosphere like the the environment that these planets are into is pretty harsh I'm more likely that no these planets cannot retain atmospheres and I plan it with an atmosphere is more than likely not habitable so one of the big questions right now is you know just because of the environment conditions do the rest of your planets around M dwarfs can actually retain atmospheres and this is how this this program came to be right so we basically have a pro that program um when jwc has five planets this is the first one that we observe and Dave is going to love this one so this is actually a theory like LHS 475 B now when we got the data or when we got uh the proposal approved wasn't even a planet yet it was it was a target of interest from Tess it was toi 910 and as you see in the Tesla curve you know it has like what appears to be very very clear transits but it had not been confirmed as a planet and the reason why it had not been confirmed as a planet is this one so the the hostar which we now know is a hostar is this red star here Sanam dwarf and there is another star that projected in the field is at a separation of 18 or seconds in principle everything is good except that the test pixel resolution is 21x seconds so in the test data those two stars appear in the same pixel so they're basically their light is basically Blended so even though Tess was saying like a really nice Transit we couldn't tell which one of the two stars the transit was coming from somehow we managed to convince it the time resignation committee that it that was okay because if this planet has a radius of one Earth radius it had to have a mass of about one Earth masses because based on just observations that we have from the solar system anything that has a radius of um one is radii or less is Rocky and it doesn't have a big large gas envelope so this planet had to be Rocky and somehow the tag bought into it and it actually gave us three observations for this particular Target uh so the first observation was in August 31st uh shortly after September 4th we had another observation we actually had a third attempt on September 27th which didn't go well and that one is free scheduled for next summer um I mean for this summer so hopefully we will have a you know a third observation soon so and these are the results from um the two transits that were successful again this was done with near spec 395 so we have data between 2.8 and 5.3 microns this is that this is an exercise Planet I mean that looks like the transit like Earth of a Jupiter to me but it's not it's earth size and you see that there is a little bit of a slope that's actually a systematic with the data and the Precision of those data points is on average will reach a Precision of 15 parts per million so but this is the white light curve basically this is like you get all the Spectra and you integrate all the light and that's the Precision that we can achieve so now if you do the same trick that I was telling you at the beginning you know you get the Spectrum you bin it into different bands in this case it's about 60 bands and you look at the changes in transit depth the black points here that's the spectrum of this planet is flat but that flatness is telling us a lot because the yellow lines that you see there those are um three atmospheres which actually contain hydrogen their hydrogen dominated atmosphere and different amounts of solar abundances of solar metallicities right so we can discard confidently that this planet does not have a hydrogen atmosphere and that has been a very good like you know a question that has been going you know around for like a few years now they say well you know every planet should form with a hydrogen atmosphere you know even if it is a terrestrial planet some of them are going to have hydrogen this guy doesn't and we can discard that like a very very high Sigma confidence so now if we zoom in I don't know if you can see this little like bluish grayish band but if you zoom in in the Spectrum this is what you see this is the same data you know the arrow bars now are a lot more prominent but still pretty much flat and again this is what we can tell from that flatness because in this case I mean it's not as much what we see about what we don't see that flatness basically tell us that even if it had like tiny little hint of hydrogen that would be like a thousand times solar metallicity that's not the answer yet you know this planet really does not seem to have hydrogen we can uh discard that model at about five Sigma the planet does not have a methane-rich atmosphere like something like Titan that's not it so if you see that like light purple line that goes off the data points a little bit that would be an atmosphere like Titan this thing is not like Titan but with the Precision of this data what we cannot tell yet is whether the planet is like Venus like Mars like Earth or if it has no atmosphere so right now on Friday we are putting a cycle to proposal to actually look at the secondary of these two uh to actually tell if it has an atmosphere or not and actually with the third data point that will come in um hopefully in the summer we will be able to make uh zero bars about 20 smaller but we still I will see that we're going to be able to tell you know if it is Avenues um so that was the last thing I wanted to show you I think I'm right on time and uh so to to wrap up the talk um you know I want to go back to to this uh slide where um I was I was showing you the targets that are scheduled between now and the end of the year the results that I've shown to you now that's just the tip of the iceberg I mean that's about two percent of the time that we have allocated and it's not even all the results that we have out I mean I can give you a heads up already we have carbon uh monoxide like our regular students are writing that paper we have a detection of carbon monoxide as well and like did there is so much more that is coming out just from this two percent of the results at least for gas giants you know exoplanets is now planetary science finally because just with those data we can already answer like pretty much all the questions that I post at the beginning you know we can tell how the planet form and evolve we can tell you what the plan is made of um how diverse the properties of these planets are we will need all this other data to answer that one and we will also be able to tell you how does Theta actually compare to other planets in the Solar System for terrestrial planets though we are still going to need something like the habitable habitable World Observatory we will be able to tell you what terrestrial planets around mdoors are made of sort of but we are going to have a really hard time pinning it down to anything that is that has an atmosphere is smaller than Venus for example so that's what I wanted to show you and you know the future is bright I would say and I'm happy to get to take your questions thank you [Applause] question all right Charles I think that's on so this is just a nomenclature question you refer to mentalicity and I'm old enough to think medalistically includes everything except hydrogen and helium but you're singling out carbon and oxygen yeah so what does metallicity mean oh it's the same it's still the same definition so for people in I mean I don't know if people are hearing but yeah so here met at least it is anything that is not hydrogen and helium and uh you know so far we have seen that everything is enriched somehow so yeah but we are also able to now look at individual elements and Elemental ratios which is something that we could not do a year ago and now it seems so easy so this is gonna be cool Sean at the uh giant planets you showed that were flat Spectrum you attributed that to clouds yeah but you didn't seem to allow that possibility for the terrestrial planet flat Springs right right right yeah yeah so the reason for yeah so so if it is a fully that's actually an extra question if that planet well first of all it could be that is fully cloudy but that cloud has to be very tenuous like it has to be like very very close to the surface of the planet because anything above that we would have we basically would have seen a much bigger planet if that was the case you know if you have something like a methane Rich Planet like Titan with a lot of clouds we would have seen it bigger and we don't so yeah that's a possibility that is totally close it out but that level of clouds has to be tiny that's uh yep that's a good question anybody else oh Charles number two plus there's also in some sense nomenclature again you didn't mention Haze and they're never completely sure in my mind what is there a distinction between Haze and cloudy and do you have anything to say yeah that's that's actually very a very good question so clouds for by condensation so basically you know the class owners you just you have water sitting around and because of gravity they condense Haze on the other hand forms by photo photo ionization so you basically have to have you know like some some kind of external irradiation in this case and the external irradiation photo dissociates whatever molecule are there and that forms a haze with jwc data thankfully we're not super sensitive to the haze because I you only see it in the um in the optical just because the the um the uh the particles of the particles that form the haze are about one micron in size so it shows in the optical and but what we are going to be able to do with um jwc but that will have to be with Miri observations between 5 and 10 microns is we are going to be able to tell you what the haze and the clouds are made of and you know and these are not clouds like clouds on Earth I mean these things are not made out of water they are made out of magnesium silicates and stuff like that so but yeah but that's that's the difference like Cloud synchronization Haze is photo Association so how many of these systems that you're going to be looking at or or that you have looked at already can you do you have any estimation of the age of the star oh yeah well to our knowledge for that I remember I think the large majority of them are main sequence Stars I think that there is a couple of young planets and there is also a couple white words like planets on a whiteboards which probably Andrew can tell me more about this but everything else I think is main sequence so anywhere between yeah and and do you have rotation periods for many of them uh yes and the ones that we don't we can get them from tests actually yeah so yep especially if they're young that's easy yep all right so when you're looking only at a small handful of transits how much do you worry about like stochastic weather you know like you know how would that affect these these results yeah I mean like for for HST sorry for jwst we don't right like what we worry about what we used to worry about was um you know like things that we're causing and like basically the the telescope and the instruments not being stable enough so we will see changes between like chances of different epochs that's not something that we're seeing like everything is super well-behaved we're seeing very little see um cortical related noise which is produced by these things here everything is for the noise we are reaching precisions which I forgot to say this at the beginning remember that I said that um the what was reported was a goal of a Precision of 30 parts per million we're reaching positions of five parts per million so anything that is at terrestrial planet we can do it as you see but to to go back to your initial questions from the ground that has been a nightmare and I think that that's really the limitation from the ground is both weather and also instrumentation that wasn't built for this well the jwc instrumentation actually like you know like exoplanets were discovered when jsw Steel uh you know started its design so the design includes observations of exoplanets while everything else including Hubble as pizza and so on this was before exoplanets even were known to exist so none of that instrumentation was was prepared for this and that's part of the headache yeah so well you set up a question I was going to ask 60 planets in the first year yeah and lots of proposals going in on Friday yes is there going to be anything for the Arielle to do left over when it launches maybe towards the end of the decade well I mean I can tell you one thing and this is uh so you know I'm also the chair of the users committee and there's going to be a call out for like what to do for exoplanets with jwst and one proposal that I have is this is a volume limited sample right we only this is not like cosmology that is like billions of galaxies that you can look at but EXO plan is you only have so many that you can actually observe so one of the things I'm going to propose is to actually have a program that observes every single planet that is observable and that is going to create a library of observations for the future that you know anybody can use um so hopefully we will not have to write proposals for exo-planners in the future but I mean that said that would be for two very very specific um modes of observations basically near aspect prison that covers from 0.5 to 5 microns I'm probably Miri from 10 to 12. but if people want to go into detail on other things then they would have to write proposals but that's the Hope right now but if you want to know about the weather you have to keep going back so there will be something for Arielle to do all right you're talking about the weather on the planets totally I sorry I totally misunderstood your question um I'm not sure we're sensitive though I haven't I haven't done calculations of like what kind of variability we will see uh so I don't know yeah sorry I totally misunderstood your question sorry sorry okay okay we're just about out of time uh we're going out for the colloquium dinner at Chang show I have one or two seats left if anybody is interested in joining us and let's thank Mercedes again for showing us the tip of the iceberg

Channel: CfA Colloquium

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Id: ldwISvjMMHU

Length: 60min 3sec (3603 seconds)

Published: Wed May 24 2023