Planetary Radio: Space Exploration, Astronomy and Science - JWST detects water vapor in a planet-forming disk

Episode Date: August 16, 2023

A team of researchers using the James Webb Space Telescope (or JWST) has made the first detection of water vapor in the inner region of the protoplanetary disc that is already forming worlds. Giulia Perotti and Thomas Henning from the Max Planck Institute for Astronomy in Germany join Planetary Radio to discuss their team's research on PDS 70 and what it can tell us about the formation of planets like Earth. The Planetary Society's most recent intern, Ariel Barreiro, reflects on her summer working with The Planetary Society, and Bruce Betts, our chief scientist, pops in for What's Up and a conversation about terminator zones. Discover more at: https://www.planetary.org/planetary-radio/2023-water-vapor-in-a-planet-forming-disk See omnystudio.com/listener for privacy information.

How do rocky worlds get their water? New data from JWST adds another piece to the puzzle, this week on Planetary Radio. I'm Sarah Al-Ahmed of the Planetary Society, with more of the human adventure across our solar system and beyond. and beyond. A team of researchers using the James Webb Space Telescope, or JWST, has detected water vapor in the inner region of a protoplanetary disk that is already forming planets. Julia Parati and Thomas Henning from the Max Planck Institute of Astronomy join us to talk about their team's research and what it might be able to tell us about the formation of worlds like Earth. But first, you'll hear from the Planetary Society's most recent intern, Ariel Barrero, as she reflects on her summer working with our team.

Then Bruce Betts, the chief scientist of the Planetary Society, will join me for What's Up and a conversation about Terminator Zones. Here at the Planetary Society, we believe that space is for everyone. No matter who you are or where you come from on this planet, we all deserve to know more about our place in space and have opportunities to work in the field if that's what we choose to pursue. As part of our organization's commitment to making the space community more inclusive, we've been very lucky to have a series of wonderful interns from the Z Factor Fellowship join our teams. Ariel Barrero, our most recent intern, just ended her time with us last week. She's here to talk about her summer at the Planetary Society and what fellowship programs like Zed Factor can do

to help people from underrepresented groups find their place in the space industry. Hey, Ariel. Hi. It's so funny because I feel like your time with us has gone by so fast. Really fast. Yeah. You just started what in June? Yeah. It feels like the blink of an eye now, though. It really does. But you're our most recent intern from the Zed Factor Fellowship. Would you mind sharing what that organization does? The Zed Factor Fellowship is great. They are helping underserved community members get into the space sector.

That's so important. There are so many people that deserve this opportunity. And classically, there have been so many barriers in the way for these underrepresented groups, yourself and myself included, to get into this field. So anything we can do to try to help people out is great. Yeah, I agree. They were really great too, because they opened it up past just engineering. So they opened up for anybody in communications, marketing. I think we even had a student who didn't really have any aerospace background at all that was able to come in and get involved.

So I think that's really, really big. What kind of opportunities does it provide for people? So they match you with a host company. And depending on your background, you kind of interview and then see who works best with you. They also place you with two mentors. And I have to say, they just did such a great job. I'm going to shout out Sarah Monero a little bit. She works in defense and she was mine and we just clicked really well.

And then obviously I clicked really well with everybody at the Planetary Society. So I think they do a really great job placing students with a host company that suits them. What in your life led you on this journey that ultimately put you with us at the Planetary Society? So I'll try to keep it short, right? I'm older, so that's my non-traditional burden to bear. And I have been in restaurants for the last 20 years. And at some point when you're in that industry, you kind of reach the top and realize there's nowhere else to go. And do you really want to do this backbreaking work for the next 30 or 40 years? So I decided to switch out. I had like a really great high school physics professor that kind of always stuck with me. And then I just got really lucky along the way. Honestly, I met women in physics, women in astronomy that just

helped me every step of the way, stay involved and push through getting a degree later in life. That's so cool. Do you have any aspirations for what you want to do in the field later? I have no idea. I feel like I learned so many new avenues being here and through the fellowship that now like where it was just scientific journalism. Now I see so many different paths. I will say a very long-term goal of mine is to work in the White House though, for sure. Now that I've seen it. I love that. Are you making any plans to potentially go to our day of action in Washington, DC? Cause I feel like that would be a great opportunity to see what that's all about. Oh my God. Yes. Big time. I've been like on Jack, like I'll be there. I'm going to help

you. I can't wait to come and be a part of this. So yeah, I have, I absolutely plan to be there for that. That's awesome. I'm really looking forward to it myself. So what's your time at the Planetary Society been like? Life-changing. Oh my gosh. The society not i'm gonna like shamelessly plug you on your own platform but just what amazing an amazing group of people you know i immediately felt comfortable meeting all of you you were just also welcoming and then working with ray specifically you know she is a wealth of information as far as science communication is concerned. And she didn't hold back in like giving me that information and just any question I had, she had an answer. And anytime I do something, she just very like diplomatically show me a better way to do things. So it's just been a

really great experience. Like I'm so sad that it's over. Yeah, Ray Paoletta is our associate producer for the show, but also our editorial director here at the Planetary Society. And I'll shout her out as well, because she's done so much for me recently during this transition into planetary radio and being someone there that I can count on to help me get through it. And that's really what it's all about. You know, if we want to make people feel safe in the space community, and make it more welcoming for other people, we got to lift each other up and be kind to one another because we're all on our learning journey no matter where we are, you know? I think that's honestly one of my biggest takeaways from working with the Planetary Society. And I said this in the beginning and it held through

the whole 10 weeks that I was with you guys is just the amount of respect that I see interplayed between everybody that works here, the way that everybody talks about their job and the work culture. Like, again, I'm old enough to know a good one when I see one. And this is like top notch, just the way everybody feels about their positions about the company, a company that's really true to its like mission and vision statement. It's just it's really great to see and be a part of. That makes me so happy to hear. But I know, you know, behind the scenes, you've been working on some of our cool communications work, and you just came out with your first article on our website. What's it called? Oh, my gosh, the whole title. I know

it's about Terminator Zones. It's our Terminator Zones, our next search for life. This wasn't necessarily something scientists were looking at before. And over the last few years, they started to think, hmm, maybe we should check this out. I love this concept. We can't get deep into this article right now because we're time limited. But if you want to learn more about Terminator Zones, I'm going to link to Ariel's article on this page for this episode of Planetary Radio. So if you want to read it, it's at planetary.org slash radio. And it's awesome.

It's at planetary.org slash radio. And it's awesome. But thanks for being here with us, Ariel, both on the show and as one of our interns. And I cannot say it enough. I really, really can't wait to see what you do next. And I wish you all the luck in the future. Oh, thank you so much. Thank you for having me.

It's really been a blast. Pun intended. And now for our main topic of the day, water and the formation of rocky worlds. Water is a necessary ingredient for life on Earth, at least as we know it. But we still aren't 100% sure how our planet ended up with its vast oceans. We can't take a time machine back to the beginning of the solar system as much as we want to. But as our technology improves, we can study other young star systems as they form their first worlds, and that can give us some insights. Our guests today are Dr. Julia Perotti and Dr. Thomas Henning from the Max Planck Institute of Astronomy,

or MPIA, in Heidelberg, Germany. They've made a discovery that can help us learn more about how rocky planets get their water. While observing a planetary system with JWST called PDS-70, which is 370 light-years away from Earth, they detected water vapor in the inner part of the protoplanetary disk. That's the region of the disk where rocky or terrestrial planets might be able to form. PDS-70 is already home to two known gas giants. So, that makes this the first detection of water in the terrestrial region of a planet-forming disk that already has two or more planets. Julia Perotti is a postdoctoral fellow at the MPIA and the lead author on this research paper. Her studies focus on the astrochemistry of young stars and their inner planet-forming disks.

Her co-author Thomas Henning is the director of the MPIA. He's the co-principal investigator for JWST's Mid-Infrared Instrument or MIRI, which was the instrument that made this detection. He's also the principal investigator of the MINDS program. That's the MIRI Mid-Infrared Disk Survey. That's the survey that took the data for this study. PDS-70 is just one of the many star systems that they're investigating. Their paper, called Water in the Terrestrial Planet-Forming Zone of the PDS-70 Disk, was published in Nature on July 24, 2023.

Hi, Julia and Tom. Thanks for joining me. Hi, Sarah. It's a great pleasure to be here. Hi Sarah, thanks for having us. It's funny because I feel very personally invested in the story, you know, surely not as much as both of you since you work on it, but for many years I taught a school program in an observatory and part of what I did was I presented the show to children about the role that water plays in our search for life and how comets might have been the vehicle that brought water to Earth. And if I had known the results of your paper, it would have completely changed my storytelling.

So, Julia, you're the lead author on this paper. So what did your team discover? Right, so we pointed the JWST Space Telescope to a very young star in the constellation of Centaurus that is called PDS 70. And while this star is not alone, it has a disk that is composed of interstellar dust and gas to the birthplace of planets. And this is a very cool system because this is the first one where we detected, with direct imaging, two giant planets during their formation in the making. We used JWST to study the innermost regions

close to the star, so an inner disk close to the star. And we detected water vapor. We detected a substantial reservoir of water vapor there. So this is what JWST allowed us to discover this year. How did you both become involved in this project? Well, it has a long history. I was getting involved in JWST more than 20 years ago. I was getting involved in JWST more than 20 years ago.

I'm actually a co-PAI of one of the instruments, MIRI, and we provided the mechanisms for the instrument. And as a return, we got guarantee time. I'm leading one of the biggest projects of this guarantee time to study the inner disks of these planet forming regions and PDSM team will argue its choice because we were the team who discovered the planets so we also wanted to know what's going on in the disk. I'm a postdoc fellow at the Max Planck Institute for Astronomy in Heidelberg and I work in the team led by Thomas Henning. And so I was really glad to be able to work on this beautiful data set and join efforts in getting a better

understanding of what is the chemical composition of the terrestrial planet forming zones in protoplanetary disks such as PDS-70. And so together with Thomas, I'm involved in what it's called MINDS survey, Miri Mid-Infrared Disk Survey. That is a GWST GTO program that will probe 51 disks. Thus, we'll be able to gather a much better understanding of physical structures of the disks in the mid-infrared and the chemical composition where planets similar to our Earth form. I love these kinds of collaborative projects because I mean you're the principal investigator for mines right Tom yes I am but I also have a cool eye uh Inga Kamp from the University of Cunningham and of course quite a

number of very active postdocs and PhD students are part of our program pd70 is only one of the many results we are getting at the moment. There are other very interesting results we are obtaining and I think JWST is a great instrument because it provides a sensitivity and also a spectral resolution to define the molecular emission in these inner disks. Despite the fact that the telescope isn't large enough to dissolve these regions, we can nevertheless get information about the molecular content of the inner disks. JWST is really changing up our ability to study these systems and not just figure out the composition of planet-forming disks, but even

analyzing the atmospheres of planets when we find them, which is just a complete game changer. Julia, why did you choose to study this star system in particular for the study? Well, so this is an iconic disk in the planet's deformation community for some of the reasons we mentioned earlier, but this is the really first disk where we detected two giant planets in the gap that separates the inner disk that I've been studying with an outer disk. And these two giant planets have been directly imaged using VLT. These are called PDS70B and PDS70C. and PDS-70C. And so this young protoplanetary system is even more attractive to the community

because towards planet PDS-70C, also a circumplanetary disk has been detected where exomoons may be forming. And so I was really extremely curious in looking at the inner disk of the system where planets like Earth may be forming right now. And so it was an obvious choice for me. It's definitely my favorite target in the survey. It's always cool to be able to take up an instrument as powerful as JWST and then study one of

your favorite star systems. That's so exciting. For a long time, the prevailing hypothesis has been that rocky planets form closer and toward their stars, and then later they're seeded by water with comets and other icy bodies that form further away and then migrate in and impact these objects. So why was that the assumption for so long? I think we have actually two competing theories for the delivery of water. One indeed was that delivery by comets, but actually more by asteroids would be the source of water.

The other theory was that small particles, small silicate particles containing water would bring the water early to the Earth and so the Earth formed wet instead of dry. The reason why we saw that asteroids are the main source of water is simply that the Earth formed in a region where we would not expect to have water at the time of formation. And on top of that, we also know that the isotopic composition, the ratio of heavy water to normal water in the asteroids, is very similar to the ocean water on Earth. So that was another reason that we saw that asteroids are important. And that could still be the case today.

So it's not that this is no longer a valid theory. But with our discovery, we actually found that there's also water early on in the zone where the Earth could form. And we now have to find out where the water actually came from. This is a real puzzle triggered by our observations. And that is the question for me, because there's kind of two ways that this could have occurred. Either the water is forming in the inner region of this planet-forming disk, or a similar situation where it's forming in ices further away

and then migrating in toward this inner part of the stellar system which of these two scenarios do you think is most likely with the current data we cannot exactly say that one rules out the other we tend to prefer the possibility that well we can have transport of gas from the outer part of the disc to the inner part of the disc so if oxygen rich gas can populate the inner disc and and therefore sustain the inner disc then if we have oxygen atoms there and we know that the inner disk of PDS 70 is reaching hydrogen, then we can form water in the gas phase. We can form water vapor, as you said. And we know water molecules being UV absorbers. So they can sort of shield the water reservoir from the UV radiation from the star so this is a viable scenario together with the dust coming from the

outer part of the disk and filtering through the gap and reaching the innermost disc regions also small dust particles ice rich particles could couple with the gas populate the inner disk could, coupled with the gas, populate the inner disk. But in that case, we would really have the silicate to play a major role to trap some of these water ice to higher temperature and therefore assure that even at temperature like 600K, 500 Kelvin, the water is still preserved and then sublimates at these temperatures together with the

with the silicates so i think this paper starts offering a clue and and the take of messages that there is water in the innermost regions of discs that are cool and faint like pds70 and that they host planets and right now I have to continue investigating the spectrum and investigating other systems and PDS-70, but all the other instruments on board of JWST to be able to disentangle which of these two mechanisms plays the biggest role. Because we've got a scenario here

where there's an inner disk and an outer disk that's separated by this large gap with protoplanets in between, would that make it any more difficult for the silicates to transport water into the inner disk? We know that this gap where the two giant protoplanets are currently assembling is gas and dust depleted and so we know from several observations and also modeling that the substantial amount of dust is not filtering through this gap this is something that would speak for also the other mechanism so filtering of the gas of oxygen-rich gas to play a role here what kind of star is at the heart of this star system, and how might that influence how much water vapor we see in the inner disk? It's actually a star which is very similar in mass to the Sun,

a little bit less massive, but still comparable at 0.8 solar masses. But it's very young, as Julia already alluded to. So the age of the system is about 5 million years compared to 4.567 billion years of the solar system so it's really a baby system and I think it's also important to realize that these systems are surrounded by two types of dust particles or solid particles. One, which is very small, around a micron, smaller than a hair, which is very, very coupled to the gas. And the other one, which we call pebbles, which are much larger, a centimeter in size, which are actually decoupled from the gas, move from the outer to the inner disk.

And indeed, the big gap makes it very difficult for these pebbles to cross. But the smaller potters could cross, and they could actually bring the water to the inner zone, and they could also bring water to relatively warm regions because silicates, at least some silicates have the property to contain water and divine water even at higher temperatures but the system is a very young one and it was actually discovered many years ago in a survey to find new young stellar objects and this was triggered by another satellite by iras which was the first infrared satellite to do surveys and then put up work at a variety of observatories

try to to find these young stellar objects and that was one which was actually discovered by astronomers in Brazil using a relatively small telescope and confirming that this is a young stellar object. It's only 5.4 million years old, but it still has this very predominant planet-forming disk. Is that a timescale on which we expect to still have a planet-forming disk around a star? This is a very good question. Is that a time scale on which we expect to still have a planet forming disk around a star? This is a very good question. If you would have asked me this question many years ago, I would have clearly answered no. Because we saw that planet formation would be a much longer process.

But now with this system, we know that these two giant planets were formed within 5 million years very rapidly, very early. And the average age of these systems, of these disks, is about three mega years. So up to three mega years, the disks are gone on average. Of course, we find older systems like TWA Hydra, which has an age of 10 mega years, and younger systems. But on average, after three mega years, the disks are gone. And that means if we want to form planets, they should have formed within this relatively short period of time. Is there any reasons that we can think why this disk still exists at this point in the star's lifetime?

Yeah, as I said, I mean, we have a variety of disk ages and some are a little bit older, some are a bit younger. That very much depends on the radiation environment from the young stellar object but also on the stellar environment if you would be in an environment which is very dense in terms of a lot of stars and the interactions may actually lead to shorter lifetimes but this object has a quite average lifetime. I think we already see that the planet formation in the gap is nearly finished because the accretion rates, the amount of matter falling onto these planets is extremely small. They will not grow a lot in the coming decades or hundreds of years or millions of years, because there is no longer any material

or very little material around, despite the fact that one has a circumplanetary disk. So one can argue that the formation of the giant planets is practically done. What is going on in the very inner disk, apart from our water detection, we don't know. We have still to find out if there are actually Earth-like planets in the inner disk. It would be a very challenging observation.

And it's always very difficult to find smaller planets, even with an instrument as powerful as JWST. It's always way easier to find the giant planets, which is a little sad because those rocky terrestrial planets are the ones that we really want to study if we want to find Earth-like planets. But Julia, is it possible that the water in this planet-forming disk is still there because the star itself is a smaller star that might not be putting out as much ultraviolet radiation? Besides the water vapor detection, there is a lot to learn still using JWST, in particular also the NIRSpec and NIRCam to understand the structure of inner disc and also with other high resolution ground-based facilities, the star itself.

Understanding whether there are stellar winds constraining even better what is the UV flux of the star. So there are a lot of missing pieces to this puzzle, but with JWST, we are starting unveiling some of the secrets of the thinner disk. That's the exciting thing. If we study enough of these star systems, then maybe we can start to get an idea of which star systems are better for having water vapor in these regions or finding these larger patterns that can tell us more about these exoplanetary systems that we're only beginning to be able to study. Thomas, in your paper, you make comparisons between PDS 70 and a star system called Doe R44. Why is that a good star system for

us to compare these findings to? In general, I think we are interested in placing a discovering context with other objects. We now have observed close to 20 low mass solar type young stellar objects, so-called deuterizedized stars which have this and the nice feature of our program is now that we have disks which are small and large this which have various masses and also different radiation environments and one hypothesis is actually that large disks would need longer time in order to transport the pebbles from the outer disk to the inner disk, and they should have less water. We now have discovered a disk which actually has a large disk, which has a lot of water in the inner regions.

So we now will be able to have a more comprehensive picture of the water distribution in the disks around these young stars. And the comparison star is just one possibility among many, I would say. Is this a situation where you've taken data on many different star systems with JWST, but you've only kind of crunched the numbers on this one star system? Or did we just not find water vapor in the same regions in these other star systems? No, no, no. We have now seen a number of objects where we see water vapor,

but the PDS-70 is the only system that we know that there is actually a planetary system and where we have imaged the inner disk. But we know other systems which are similar, but we don't have seen the planets yet we are still hunting for the planets and other systems but we have seen water in quite a number of objects now that was actually

already discovered by spitzer but now we see it in a glory detail and we will find out how the water is actually transported to the energies but we not see water, we also see something which I find extremely surprising. We see hydrocarbons and even benzene in disks around LOMAS stars and brown dwarfs. And that is really very strange because you also would expect oxygen-rich material in these environments, but we do see completely different

compositions. That is very interesting. And the complexity of these molecules that we're detecting can tell us a lot about their development, but we definitely need more data. I wish we had an entire bank full of just every star system we'd studied in the composition, but we're limited in time with what we can observe with JWST, unfortunately. I think we already have quite a good collection. At the end of our program, we will have observed about 60 to 70 objects. Other colleagues will observe additional sources. We already have a very nice program accepted for groundwork. So I think we will get a very nice program accepted for ground work this so i think we will get a very

comprehensive picture and on top of that we are hunting for more directly image planets both from the ground and with jdst so i think the real goal is of course to connect these birthplaces uh with the properties of the planets i think that that is a hot topic in the exoplanet community and in the community of people investigating that information process. We'll be right back with the rest of my interview with Julia Perotti and Thomas Henning after this short break. I have an urgent message for all American Planetary Radio listeners. Space science needs your help. Congress has proposed the first cut to NASA's budget in a decade, and missions like Dragonfly, Veritas, and Mars Sample Return

are facing shrinking budgets, delays, and even cancellation. Our elected leaders in Washington need to hear from you. Reverse course and fund NASA's innovative science programs. On September 17th and 18th, join the Planetary Society in Washington, D.C. for the annual Day of Action. This is our return to in-person, and the timing couldn't be better. While partisan politics today sows division, space is something that can truly unite us all. As a part of the Day of Action, you will receive an all-inclusive advocacy training, briefings from experts, a minimum of three scheduled meetings with your lawmakers, and the opportunity to shape the future

of space exploration. Go to planetary.org slash dayofaction to learn more and sign up. With your voice, you can speak up for space science. With your passion, you can inspire others to take action. Join us. Are there currently any other ground base or space observatories that are looking at this system in particular to try to follow up on these results? system in particular to try to follow up on these results well for when it comes to pds70 triers for example very large telescope it's has been looking at this system observing the system also targeting the inner disc but different wavelengths compared to what we did with with gwst so definitely providing complementary high resolutionresolution data, for example. And as I was mentioning earlier, as part of the MIND survey,

also near-spec observations of PDS-70 have been taken and of NIRCAM. So this system will be observed with all four instruments on board of GWDST. That's why it's particularly exciting because for this particular system, we can use all the great capabilities of James Webb. How long is it going to take for this project to complete, to study all these different star systems? Yeah, I think we should have completed the program in terms of observations in summer next year. We get such amazing harbors that it will take a couple of years to publish everything and to investigate everything. I think we have really a wonderful data set and the next paper is already submitted or

coming out. I guess the next two to three years will keep us busy. The spectra are extremely rich, as we were talking about. It's amazing to see, first of all, and at the same time, it requires a detailed analysis and also development of tools to perform an accurate interpretation of the result. But it's really great to see all this data coming in and we're constantly surprised when when

we start looking at the data set new data set that gwsg provided us with yeah we mainly talked about the gas but we also get of course a lot of information about these small solid particles and in this particular system we have seen that we have amorphous silicates, but also crystals. Actually, some of the crystals have a color very similar to the Green Beach in Hawaii. I mean, the olivines. And they tell us a lot about the thermal history of these disks. And that's also another topic of research we have at the moment. So it's not just gas, it's also the dust.

And both components together are important ingredients of the planet formation process. And that's an important thing to note as well, because Earth is very rich in olivine. So we might be seeing these planets forming in a way that's very similar to Earth's past. If they form, when they form, once we find them. Yeah, absolutely. I think, as I said, the crystals tell us a lot about the thermal history of the systems. And one thing we also would like to find out is, of course, the ratio of carbon to oxygen. Because from Earth, we know that we have a very carbon poor

planet that sounds very strange but it is the case compared to the carbon we could expect from the interstellar medium we also have a very nitrogen poor planet again something very surprising if you think about living systems and we have to find out what the reason is what is carbon and nitrogen deficiency and one possibility is indeed that the carbon is somehow destroyed in these inner planet forming zones and in a number of objects we actually do not see a lot of carbon but in the low mass stars we do so we have to study the diversity of planet forming regions. And I think this diversity in composition may later be reflected in the diversity of compositions

of exoplanets which form in these environments. It was only recently I was speaking with one of the people on the team that detected phosphorus in the oceans of Enceladus. And we got into a very deep conversation about the impacts that the distribution of carbon dioxide across a solar system can have on what water is able to absorb and how it impacts these worlds. So understanding more of that carbon distribution could tell us a lot about those oceans if and when they form as well. Absolutely. And I mean, we find it a lot of different molecules apart from water. We find CO, CO2, OH, HCN, this around the Lomas stores, we find C2H2 or benzene.

So a large family of molecules and HCN is a particularly interesting molecule because it's a key molecule in the origins of life field. It is often used as a molecule to produce amino acids but also RNA precursors. So HCN is really a molecule which is very close to my heart because of my interest in the origins of life. This finding has some really interesting implications in the search for life because life as we know it requires water and the timeline for how these planets get water could change a lot. Can this result tell us anything about, say, the history of how water came to Earth? tell us anything about, say, the history of how water came to Earth? Yeah, well, again, as I said, we are trying to understand what is the most dominant scenario for the origin of water in PDS-70, and being the star cooler and less massive than our sun, but still comparable that's it's really the best test bed that we have right now what we also

have to do is to combine the information that we obtain with gwst with also upcoming alma observations and in my opinion and to be able to constrain further whether our oceans on earth are mostly due to asteroid impacts or water coming from the inner disk we also have to study for example the deuterium deuterium to hydrogen ratio that would be an important piece in this puzzle to be able to answer however it's very difficult for PDS-70, for the star, which is so faint, to be able to detect deuterium and therefore estimate the deuterium to hydrogen ratio. But for other sources, for the stars that are brighter than PDS-70, that might be possible. So that would be a key question to answer, in my opinion. I'm wondering, we can't actually do this, right? We can't take a planet and slice it in half

and see what the entire planet is made of from the inside out. But if we did have a scenario where these planets formed with water with them in the disk, could that have any impacts on, say, the hydration of the minerals as you went into the planet? Would it have any impact that we could detect in its composition? We'll have to look at, for example, deuterium and to see if the isotopic anomalies that we detect on Earth, they resemble to the ones in the inner disk during the formation of terrestrial planets.

It is challenging to do, observationally speaking, at the moment, but that would be a way to do it. I mean, the meteoritic community is actively discussing what kind of meteorites or better asteroid material entered earth early on was more iron material or was it material which is also carbon based and contained water and at the moment i think there is no clear decision made but if there was also a lot of water coming, then that would be a great connection to our own discovery. And I think Julia is completely right that deuteration is a key element of the story, but also is certainly the nitrogen isotopes. And deuteration is important because our ocean water is actually not from this world and what i mean with this is that it has a content of heavy water which can only be formed at very low temperatures so we somehow have water which has a signature of low temperatures and the question is this is also true for the water in PDS-70

or for the water in other disks around young stars? And indeed, in the near-spec waveplanes range, one could observe HTO if one is a bit lucky. And of course, we hope to be lucky and have another nice discovery of deuterated water in the infrared. I think this will be very difficult for PDS-70, but we have a number of other targets which are very water-rich and I guess should be possible. What other targets are upcoming in your studies on this? I mean, one is AOTA, which is a very water rich source.

We will get near spec data says in the infrared data, not only miri data, but a million for ad and let's see if you find due to either water in this system. That's an interesting point to make about the fact that the water on Earth shows shows evidence that it formed somewhere else and like migrated in. This could be a very complex situation where some of the water was already here when the planet formed and then on top of that water from other places that formed in cooler environments then migrated in and created this interesting kind of cocktail of water from different locations. Some of the other targets that will be observed as part of the MIND survey are

Ejon compared to PDS-70, which is face-on. And the fact of having this Ejon configuration means that WGW-ST will be able to probe the mid-plane, so really the region where planets are forming, and in the near-spec range, we'll be able to study water ice. So not only water vapor, but also the composition of the dust grains. So that's also going to be a really important analysis, an important step of the program and general answer question with the community. What is the abundance of water ice in disks?

That would be useful too, because if it's edge on, it might be easier to detect the planets in that system instead of just seeing them directly as you did in this situation. But instead, you could see them transit in front of their stars. Given the buzz around this, how do you think it might impact future research or funding priorities for JWST studies? One thing we will certainly do is we study the disk properties as a function of mass of the central star. I mean, most of the Earth-like planets or rocky planets we find today are actually orbiting so-called M-type stars. These are stars which are less massive than the Sun.

And the disks around these stars are poorly investigated. The reason is simply that our previous observatories like Spitzer, they were just not sensitive enough to do a good job. They only could investigate a few objects. So I think this is one thing we would like to do. The other thing we are already doing now is together with another colleague, the solar system was probably formed in a cluster environment. What I mean with this is that it wasn't formed alone,

but there were a lot of stars around. There was a lot of UV light. And the question is, what is actually the composition of this in regions where we have such clustered star formation? Because all the nearby objects we observe are relatively isolated, and we have observed such a disk. And in this case, we actually don't see a lot of difference. We see that the disk is much smaller than our disk,

but the inner disk composition seems to be similar. So I think to investigate disk and clusters will be another important goal. I'm really looking forward to it. I just cannot wait until we have so much information about these things that we're bored of studying exoplanetary systems. And it just seems old hat because I mean, this kind of information, even just the plane detection of worlds when I was a child was a thing that lit my imagination on fire to the point where

I dedicated my whole life to studying astronomy and astrophysics and planetary formation. You know, like these are the kinds of discoveries that inspire the future. So I'm really happy that you guys are dedicating so much time and thought to this. I think we have a lot of fun. Yes, absolutely. And it was the great machine, you know, it's really working very, very well. And so many people made it possible. And I think we now have the harvest and it's just wonderful.

I'm really hoping that all of the studies that come out of JWST help us justify building more and more of these, maybe even a whole suite of them in different parts of the spectrum. Just create a new system of great observatories based off of JWST because this one telescope is completely changing so much of what we know about planetary formation and exoplanets in general. And we need more of this. Yeah, I think the exoplanet community is also getting a lot of exciting results. And of course, this also paves the way for an observatory, which we may have in about 20 years from now,

where we want to observe Earth-like planets directly and characterize the atmospheres. And at some point, we would like to look for evidence for life by infrared spectroscopy or optical spectroscopy. So I think exciting times. Well, thank you both for joining me and for doing this amazing study. And I would love to hear more when you analyze more of these systems and might be able to make more comparisons between them, because this could really change the way we think about how water transports to these terrestrial worlds. Thank you.

Thank you very much, Sarah. It's been a great pleasure to be here on the Planetary Radio with you. It's amazing how far the field of exoplanet studies has come. When I was born, we hadn't even discovered any planets outside of our solar system yet. Just a few decades later, we've detected over 5,000 exoplanets, and we can study the composition of protoplanetary disks hundreds of light years away. I can only imagine what discoveries lie ahead of us, or what they might tell us about our place in space. There's a lot to look forward to. Now let's check in with Bruce Betts, the chief scientist of the Planetary Society, for What's Up.

Hey, Bruce. Hey, Bruce. Hey, Sarah. It's funny. Earlier in the show, I had an opportunity to talk to our latest intern from the Zed Factor Fellowship, Ariel, and I feel like her time with us completely disappeared. Like she came here in June and she's already done her whole time. Like how do things move so fast? The relativistic time in our brains is something that I very much do not understand. But Ariel's new article was all about Terminator zones. And I realized we didn't

actually get an opportunity to explain what Terminator zones are or what tidal locking is. So would you mind explaining as our chief scientist would you mind explaining what tidal locking is and how that could make planets really weird for life sure uh yes so tidal locking is uh we have half the system tidally locked in our system with the moon always facing one side of it towards the earth it's basically when you get a large gravitational body and you get a small one hanging out near it the small one gets grabbed by tides that it just wants to face one face always towards the face of the other face i did not describe that very well but bottom line is we can end up with a lot of tidal locking.

Let's move on to the Pluto system, shall we? Because that's interesting, because Pluto and its large moon, Charon, or Charon, are tidally locked in both respects, so that Pluto always faces the same side to Charon, as well as Charon always facing the same side to Pluto, and that's because they're somewhat comparable in size. Although Charon is smaller, it's a significant fraction. So over time, tides grab onto each other. And because they're not perfect spheres, but they have mass distributions, you can end up with this situation. Now you go to a star system, and if you put a planet close enough to a star, it will end up getting tidally locked. So it will always face one side of the star, which tends to make that side hot and crispy.

As you get farther away from the parent star, you don't have enough tidal interaction to do tidal locking. So what Ariel's talking about is this recent research on M dwarf or red dwarf stars that are lower mass but still very massive and lower temperature and so when you put a planet close enough to get tidally locked you could conceivably come up with happy little temperatures except it gets tidally locked so you end up crisping one side of the planet that's always facing the star and freezing the other side of the planet ah but that's where we talk about the terminator the terminator in planetary world is the line between day side and night side it's between dark and light oh sounds kind of like something out of star wars and so the light side is getting fried in the dark side it's getting frozen and so people have now researched

and she's talking about the fact that in between you can depending on the situation on the planet surface end up with a happy little temperature in between that might be stable. So you might have a strip following this terminator zone where you end up with the situation conducive to even having liquid water and therefore the potential for life. But it gets tricky, tricky, tricky, and she talks about the details, which I will leave to the article. It's one of the first research papers focusing on this. So we'll see where the science evolves.

But it's an interesting exercise to think that these planets that offhand you would say, oh, it's just bad for life. But maybe, maybe not if you have the right situation. How's that? It's good. I like that science is getting on this because I was introduced to this concept through sci-fi primarily. And I'm glad that you brought up Star Wars because when we posted this article

in our member community, we actually had a member write in. It was Devin O'Rourke from Colorado who mentioned that the Twi'lek species in Star Wars was actually from a Tile-Lock planet and they only lived in the Terminator zone. So that's one example. I've read many books in sci-fi where they just live in this beautiful little twilight zone all the time.

But woe unto you if you get too far away from that nice little temperature zone, or you're either going to crisp or you're going to freeze. Come with me if you want to be habitable. So funny you mentioned that that because I was just watching Terminator 2 this last weekend. I think a bunch of people on staff ended up watching Terminator this weekend because of this article. Alright, well I'm sure this topic

will recur and we'll be back. So what's our random space fact this week? That seemed like a lot of facts, but let's go with the random space fact, because that wasn't random. We're talking dwarf planets and their friends. You've got to do your random space fact. Oh my god, I'm so thrown off.

Random space Fact! So, dwarf planets. We got Pluto, we got Eris, Haumea, Makemake, and Ceres right now. But there are others that, with more data, will probably end up being classified as dwarf planets. And in fact, interesting little point, this is really the kernel of the random space fact. little point. This is really the kernel of the random space fact. There are four objects that in mass

are more massive than Ceres, or in diameter I should say, and in mass are either more massive or very similar that are out there, which all have names that are either fun or very hard for me to pronounce. We've got Gong Gong,

Quarwar. Quar war? Quar war. Quo war? I'm sorry. I just, I believe the proper pronunciation is quar war war war war war war war. That's so not true.

It's not true at all. I just enjoy saying that. It's kind of like when you talk about the cloud, I can't, I can't say it without doing that. So anyway, we have gong gong, quar war, Sedna, and then Sharon. when you talk about the cloud i can't i can't say it without doing that so anyway we've gone gone korwar sedna and then sharon itself uh is actually more massive considerably than series and larger in diameter and so the the there are other objects that are out there series being the smallest

of the dwarf planets and the only asteroid in the gang. And even getting very, very close, and this one also can be fun, Orcus. Orcus. Orcus, which has a moon that's fun to say, too. Vanth. So anyway, as more data comes, look for more things to be classified as dwarf planets there's more stuff that's just what we found out past neptune and the trans-neptunian objects there's undoubtedly more good stuff out there so whatever you call them dwarf planets uh planets dwight

they are still quite intriguing interesting and worlds that are big enough to be fascinating in and of themselves. I always try to mention that whenever people are sad that Pluto got reclassified. Like, Pluto is one of the coolest dwarf planets. I'm not sad about it at all. Especially knowing that it's tidally locked to Charon and Charon is tidally locked to it. They're doing this beautiful kind of almost romantic dance in space together. Yeah. no, there's all sorts of good interesting stuff going out there. Too bad it's so hard to observe, but we're getting better. I also wanted to share with you, Bruce, and with everyone else that this was the first week that we did our space trivia contest in our member

community. And I've been really grateful for people's feedback on it because it's been a lot of fun. And this week, we actually got to do a multiple choice question. So I'm really looking forward to doing more of this in the future. We had some people write in and say that this was just one more reason why they feel like the Planetary Society community is one of the best places that they've been. Between that and our book club, I feel like it's a really good time. So if anybody wants to join us in the community, just need to be a planetary society member and you can check it out at community.planetary.org or download our app.

We have an app now. We have an app. We have an app for that. All right. That's cool. All right, everybody go out there. Look up the night sky.

Think about dolphins going along, just past the surf line, chilling hard, flipping around and being dolphins. Thank you and good night. We've reached the end of this week's episode of Planetary Radio, but we'll be back next week to discuss the slow evolution of Jupiter's moon Europa. the slow evolution of Jupiter's moon Europa. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by our curious members. You can join us as we puzzle over the formation and beauty of the worlds around us at planetary.org. Mark Hilverda and Ray Paletta are our associate producers. Andrew Lucas is our audio editor.

Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser. And until next week, Ad Astra.