How many countries were involved in the study? Countries! Oh, so we have some people from France, people from US, people from Taiwan, and people from Belgium. So we have four countries. And how many people were involved in this study? Let me check exactly the number of people if I can. I think we were like ten people? I can check directly. There are one, two, three [counts]. We are eleven people. And what are their roles? Oh, the roles of the other people? Okay, so the other people contributed to the interpretation of the data, mostly. So once we have done the observation, we need to understand what we are observing. So we need to compare the observation with models for instance. So, a lot of people contributed to this comparison. Some people contributed to making a link with the previous data we have with ALMA. And that's basically the role of the other people. And some of them also contributed to the writing of the paper. Yes. Um. Well the challenges [are]: first, to get very good observation; and, well you know, when you observe at the telescope, sometimes the conditions are good, sometimes they are not so good. And I think we were very lucky to have very good — extremely good condition, in fact. So the fact that we see very clearly something is also related to the quality of the data, the quality of the telescope, of the instruments. So that's the first challenge to get the data with a very good quality. And then the second challenge is to compare the observation with the models. Because there are many models. Some are more or less complex. Some are very detailed. Some are less detailed. And you have to figure out which one is the most appropriate for the comparison. Because you don't want to make an interpretation that is too far. You don't want to conclude something that is not very correct. So you need also to make sure that you use the right model. And so, you use one of the models that exists. It's not the most sophisticated. It's the one, on the opposite, which is almost the simplest. Because it's enough to interpret the images, in fact. So now, of course we need to think about models that are more detailed in order to explain the observations. Coronagraphy of the Sun Astronomers using adaptive optics at a Very Large Telescope in Chile. Which technologies were used on this study? So we use a technology called which is something which is integrated into the instrument which is able to correct for the . So, when the light from the star cross[es] the of the , it becomes blurred. And we are correcting this blurring in order to have very very fine detail on the images. So that's one of the one of the technolog[ies] we are using. Sun's corona: the outermost part of the Sun's atmosphere. The second one is . So exactly like a system which is able to observe the . So you block: when you block the Sun and you try to see around the Sun, well it's the same sort of technology but applied to stars instead of the Sun. So all the stars — and so the stars are much smaller — and this system is able to block the light from the star, so you can see everywhere around, and look for planets, look for discs, look for structures. These are the two main technologies we used. Why were these two technologies ideal for this study? Oh, um yeah, it's not the only ones but yeah, they are necessary to perform this study, definitely. Yeah. What makes this study unique? Well, it's not unique because we have already many observation of planetary systems. We have a lot of observation of disks — protoplanetary disks — and especially SPHERE has observed a lot of them. We also have images of planets. And we know that planet are forming inside disks: inside protoplanetary disks. And we know that planet should generate structures like spirals in a disk. So we knew from the theory that planet and spirals are connected, but we never ever made the connection between the two. So we never observed in the same system a planet and the spiral, ok. So here, we don't have exactly observed that because we did not detect the planet, but we detected the presence of the planet in the structure of the spiral. So we are getting one step closer to making the connection between the planet and the spirals, and the structures in the disk. What is currently the best explanation for the formation of exoplanets? There are several scenarios for forming exoplanets and we have only — we never witness planet formation, so we only have theories, which are based on a lot of observations, of course, including observations of the Solar System, planet in the Solar System, et cetera. The analysis of rocks on the Earth as well in the Solar System. But we [have] never seen a planet forming. So, there are several theories. One of them is that you have rocks forming into the system. And these rocks are colliding, they are making bigger rocks. Bigger and bigger. And when this rock has reached a mass which is large enough, like maybe ten times the mass of the Earth, then this big rock, this big planet, starts to accrete the gas. And it becomes a giant planet like Jupiter or Saturn. So that's the theory for forming a giant planet. 1321 times heavier than the Earth, Jupiter is the largest planet in the Solar System. So what kind of exoplanet will this be if this planet forms? It will be a giant planet, really. Maybe even bigger than Jupiter. Maybe 10 times the mass of Jupiter. But it couldn't be a planet that is like the Earth. If it were a planet like the Earth, it wouldn't make this kind of spiral. The spiral would not be detectable, in that case. So it's necessarily a very big planet. Artist's impression shows a hot Jupiter planet orbiting close to one of the stars So, is it safe to conclude that it could be a ? No, it's not a hot Jupiter. Because, well hot Jupiter means two different type[s] of planets. Jupiter can be hot if it is very close to the star. And this is usually what we refer when we say hot Jupiter. But, when a planet like Jupiter is forming, then the temperature is very high. It's like one thousand, maybe two thousand degrees. So, it's also a hot Jupiter. But not because it's close to the star: because it's young, okay. So here, we are talking about a young Jupiter planet which is probably very warm. What do we know about the planetary system that is being formed? Well we don't know much, in fact. [laughs] We know we know a little bit about the edge of the system. We know the quantity of gas and dust that is there, and which will form planets anyway. But we don't know yet how many planets are formed; if this planet will survive, et cetera. So there's still a lot to be understood about this system. Artist's concept of an exoplanet being devoured by the host star. Why do you think this planet may not survive? [...] As you mentioned we do not know if this planet is going to survive. Yeah, because some planets: some planet form in the disk, okay. If you have a planet forming in the disk, then the disk is made of gas. And when the planet rotate[s] around the star, then there is a friction with the gas. And so the planet slow[s] down. And when it slow[s] down, it gets closer to the star. And eventually, it can be a hot Jupiter. And sometimes, it can even disappear into the star: swallowed by the star. So we know that some planets are forming in systems and they finally end up merging with the star. They disappear into the star. So we don't know if all planets survive, in fact. Well this one is probably like 30 [an astronomical unit is the distance from the Sun to the Earth, about 150 million km; 93 million miles] away from the star. So it's very far away. There's not a lot of change for this planet to migrate very close and disappear in the star. But we know that it can happen. Could you tell us more about the host star? The star is more massive than the Sun. It's 2.4 times the mass of the Sun [mass of Sun = about 2×1030 kg]. It's also very young, as I said, only a few million years. Yeah. Essentially that's the two parameters. And what do we know about the history of the system? Not much. [laugh] Unfortunately, not much. No. We don't even have an exact measurement of the age. Because it can be between like one and five million years old. So it's not very accurate. This host star is a star, right? Yeah, yeah. What are some of the typical characteristics of a Herbig Ae star? They are very bright. Because they are very massive, so it's essentially the mass of the star which makes it an Herbig star. And they have also a lot of emissions. So, when we started observing star with , we realised that it had signatures in the spectrum, and in fact, the reason why they have signature is because they have an environment of gas. So, the light from the star is traveling through the gas, and creates some absorption, or emission in some cases. And we see this is a signature in the spectrum. So, the fact that it's a Herbig Ae star means in fact, that it is surrounded by a disk. How common are these stars? Oh, I don't have a clear idea of that. [laughs] [I] cannot answer. And how often do Herbig stars have orbiting planets? I don't know if we have already example. I don't think we have many example[s] of planets around the Herbig Ae star. It could be it could be one of the first, in fact, yeah. Not many. What kind of atmosphere will this potential planet [be] likely to have in future? Well certainly a gas planet; so with an atmosphere of hydrogen and , in majority. How many spirals were observed? So in the central part we see at least two big spirals. But in fact, all these spirals have little structures, so we see a lot of them. But mostly in the very inner part. And then, if you look at the very outer part, then you see a lot of a lot more spirals. But we believe that these ones are not due to planets, but more to instabilities. Were these two spirals interfering? Um, yes, probably! Probably. Yeah, if you have more planets in the system, then they all launch spirals. And all of them interfere. How big were these spirals? How big? They can be several several hundreds of astronomical units. What does the next few million years for this system look like? Probably that in one million year the planet will be formed. And most of the gas will be dissipated. So, all the disk we see in the image will disappear and we will be left with planets. Or maybe it will take more than one million year. Maybe five or ten. That's the point. We don't know exactly. Planet K2-33b is the youngest fully formed exoplanet ever detected so far. If that is the case this will make it the youngest discovered exoplanet so far, right? Yes, if it is an exoplanet, then it's the youngest, yeah. When do astronomers use of the stars? Well we use an infrared because it's the wavelength where we can use adaptive optics also. So with adaptive optics, we can provide very detailed images. And we need to resolve the very central part of system so we need adaptive optics. So near-infrared is interesting because you can use adaptive optics, and also because it's the range where you expect a planet to be very bright. If you look in the visible [light range], the planet will be very faint. How do you test your hypothesis? How do we test the hypothesis? Of what — Of the planet? Of the object being the planet? Yes. Well, again I think it's: at the moment the only test is to compare with the models. That's the only thing we can do.
How many countries were involved in the study? Countries! Oh, so we have some people from France, people from US, people from Taiwan, and people from Belgium. So we have four countries. And how many people were involved in this study? Let me check exactly the number of people if I can. I think we were like ten people? I can check directly. There are one, two, three [counts]. We are eleven people. And what are their roles? Oh, the roles of the other people? Okay, so the other people contributed to the interpretation of the data, mostly. So once we have done the observation, we need to understand what we are observing. So we need to compare the observation with models for instance. So, a lot of people contributed to this comparison. Some people contributed to making a link with the previous data we have with ALMA. And that's basically the role of the other people. And some of them also contributed to the writing of the paper. Yes. Um. Well the challenges [are]: first, to get very good observation; and, well you know, when you observe at the telescope, sometimes the conditions are good, sometimes they are not so good. And I think we were very lucky to have very good — extremely good condition, in fact. So the fact that we see very clearly something is also related to the quality of the data, the quality of the telescope, of the instruments. So that's the first challenge to get the data with a very good quality. And then the second challenge is to compare the observation with the models. Because there are many models. Some are more or less complex. Some are very detailed. Some are less detailed. And you have to figure out which one is the most appropriate for the comparison. Because you don't want to make an interpretation that is too far. You don't want to conclude something that is not very correct. So you need also to make sure that you use the right model. And so, you use one of the models that exists. It's not the most sophisticated. It's the one, on the opposite, which is almost the simplest. Because it's enough to interpret the images, in fact. So now, of course we need to think about models that are more detailed in order to explain the observations. Coronagraphy of the Sun Astronomers using adaptive optics at a Very Large Telescope in Chile. Which technologies were used on this study? So we use a technology called which is something which is integrated into the instrument which is able to correct for the . So, when the light from the star cross[es] the of the , it becomes blurred. And we are correcting this blurring in order to have very very fine detail on the images. So that's one of the one of the technolog[ies] we are using. Sun's corona: the outermost part of the Sun's atmosphere. The second one is . So exactly like a system which is able to observe the . So you block: when you block the Sun and you try to see around the Sun, well it's the same sort of technology but applied to stars instead of the Sun. So all the stars — and so the stars are much smaller — and this system is able to block the light from the star, so you can see everywhere around, and look for planets, look for discs, look for structures. These are the two main technologies we used. Why were these two technologies ideal for this study? Oh, um yeah, it's not the only ones but yeah, they are necessary to perform this study, definitely. Yeah. What makes this study unique? Well, it's not unique because we have already many observation of planetary systems. We have a lot of observation of disks — protoplanetary disks — and especially SPHERE has observed a lot of them. We also have images of planets. And we know that planet are forming inside disks: inside protoplanetary disks. And we know that planet should generate structures like spirals in a disk. So we knew from the theory that planet and spirals are connected, but we never ever made the connection between the two. So we never observed in the same system a planet and the spiral, ok. So here, we don't have exactly observed that because we did not detect the planet, but we detected the presence of the planet in the structure of the spiral. So we are getting one step closer to making the connection between the planet and the spirals, and the structures in the disk. What is currently the best explanation for the formation of exoplanets? There are several scenarios for forming exoplanets and we have only — we never witness planet formation, so we only have theories, which are based on a lot of observations, of course, including observations of the Solar System, planet in the Solar System, et cetera. The analysis of rocks on the Earth as well in the Solar System. But we [have] never seen a planet forming. So, there are several theories. One of them is that you have rocks forming into the system. And these rocks are colliding, they are making bigger rocks. Bigger and bigger. And when this rock has reached a mass which is large enough, like maybe ten times the mass of the Earth, then this big rock, this big planet, starts to accrete the gas. And it becomes a giant planet like Jupiter or Saturn. So that's the theory for forming a giant planet. 1321 times heavier than the Earth, Jupiter is the largest planet in the Solar System. So what kind of exoplanet will this be if this planet forms? It will be a giant planet, really. Maybe even bigger than Jupiter. Maybe 10 times the mass of Jupiter. But it couldn't be a planet that is like the Earth. If it were a planet like the Earth, it wouldn't make this kind of spiral. The spiral would not be detectable, in that case. So it's necessarily a very big planet. Artist's impression shows a hot Jupiter planet orbiting close to one of the stars So, is it safe to conclude that it could be a ? No, it's not a hot Jupiter. Because, well hot Jupiter means two different type[s] of planets. Jupiter can be hot if it is very close to the star. And this is usually what we refer when we say hot Jupiter. But, when a planet like Jupiter is forming, then the temperature is very high. It's like one thousand, maybe two thousand degrees. So, it's also a hot Jupiter. But not because it's close to the star: because it's young, okay. So here, we are talking about a young Jupiter planet which is probably very warm. What do we know about the planetary system that is being formed? Well we don't know much, in fact. [laughs] We know we know a little bit about the edge of the system. We know the quantity of gas and dust that is there, and which will form planets anyway. But we don't know yet how many planets are formed; if this planet will survive, et cetera. So there's still a lot to be understood about this system. Artist's concept of an exoplanet being devoured by the host star. Why do you think this planet may not survive? [...] As you mentioned we do not know if this planet is going to survive. Yeah, because some planets: some planet form in the disk, okay. If you have a planet forming in the disk, then the disk is made of gas. And when the planet rotate[s] around the star, then there is a friction with the gas. And so the planet slow[s] down. And when it slow[s] down, it gets closer to the star. And eventually, it can be a hot Jupiter. And sometimes, it can even disappear into the star: swallowed by the star. So we know that some planets are forming in systems and they finally end up merging with the star. They disappear into the star. So we don't know if all planets survive, in fact. Well this one is probably like 30 [an astronomical unit is the distance from the Sun to the Earth, about 150 million km; 93 million miles] away from the star. So it's very far away. There's not a lot of change for this planet to migrate very close and disappear in the star. But we know that it can happen. Could you tell us more about the host star? The star is more massive than the Sun. It's 2.4 times the mass of the Sun [mass of Sun = about 2×1030 kg]. It's also very young, as I said, only a few million years. Yeah. Essentially that's the two parameters. And what do we know about the history of the system? Not much. [laugh] Unfortunately, not much. No. We don't even have an exact measurement of the age. Because it can be between like one and five million years old. So it's not very accurate. This host star is a star, right? Yeah, yeah. What are some of the typical characteristics of a Herbig Ae star? They are very bright. Because they are very massive, so it's essentially the mass of the star which makes it an Herbig star. And they have also a lot of emissions. So, when we started observing star with , we realised that it had signatures in the spectrum, and in fact, the reason why they have signature is because they have an environment of gas. So, the light from the star is traveling through the gas, and creates some absorption, or emission in some cases. And we see this is a signature in the spectrum. So, the fact that it's a Herbig Ae star means in fact, that it is surrounded by a disk. How common are these stars? Oh, I don't have a clear idea of that. [laughs] [I] cannot answer. And how often do Herbig stars have orbiting planets? I don't know if we have already example. I don't think we have many example[s] of planets around the Herbig Ae star. It could be it could be one of the first, in fact, yeah. Not many. What kind of atmosphere will this potential planet [be] likely to have in future? Well certainly a gas planet; so with an atmosphere of hydrogen and , in majority. How many spirals were observed? So in the central part we see at least two big spirals. But in fact, all these spirals have little structures, so we see a lot of them. But mostly in the very inner part. And then, if you look at the very outer part, then you see a lot of a lot more spirals. But we believe that these ones are not due to planets, but more to instabilities. Were these two spirals interfering? Um, yes, probably! Probably. Yeah, if you have more planets in the system, then they all launch spirals. And all of them interfere. How big were these spirals? How big? They can be several several hundreds of astronomical units. What does the next few million years for this system look like? Probably that in one million year the planet will be formed. And most of the gas will be dissipated. So, all the disk we see in the image will disappear and we will be left with planets. Or maybe it will take more than one million year. Maybe five or ten. That's the point. We don't know exactly. Planet K2-33b is the youngest fully formed exoplanet ever detected so far. If that is the case this will make it the youngest discovered exoplanet so far, right? Yes, if it is an exoplanet, then it's the youngest, yeah. When do astronomers use of the stars? Well we use an infrared because it's the wavelength where we can use adaptive optics also. So with adaptive optics, we can provide very detailed images. And we need to resolve the very central part of system so we need adaptive optics. So near-infrared is interesting because you can use adaptive optics, and also because it's the range where you expect a planet to be very bright. If you look in the visible [light range], the planet will be very faint. How do you test your hypothesis? How do we test the hypothesis? Of what — Of the planet? Of the object being the planet? Yes. Well, again I think it's: at the moment the only test is to compare with the models. That's the only thing we can do.