Exploring planetary atmospheres line by line with Dr Mattia D'Arpa

Welcome to Growing Worlds, the podcast where we explore the science of exoplanets through conversations with early-career researchers on the front line of discovery. I'm Lorenzo.

And I'm Jenny. In each episode, we meet a guest who takes us behind the science of planets, stars, and the search for life in the universe.

Today we are looking through a different kind of window, one shaped by mirrors, instruments and the atmosphere of our own planet. Because even from the ground we can catch the faint fingerprints of alien worlds hidden in starlight.

And to guide us through how astronomers are using high resolution spectroscopy from Earth to reveal the composition and motion of exoplanet atmospheres, we're joined by Dr. Matthea Darper from INAF in Palmero. Matthea, welcome to Growing Worlds.

Thank you so much for inviting me. It's a pleasure being here.

Mattia is a postdoctoral researcher at the Instituto Nazionale di Astrofisica in Palermo, where he studies extraplanetary atmospheres using high-resolution spectroscopy, which is one of the most powerful tools that we have for detecting the molecules and the wind that shape alien skies. He earned his PhD by characterizing hot Jupiter and ultra-hot Jupiters, focusing on how the spectra can reveal dynamical processes such as atmospheric escape and high-speed winds. INAF, Mattiaf is part of several international collaborations using cutting-edge instruments such as harps, giano and espresso, which unfortunately is not the Italian coffee.

Hehehe.

and he combines their data with space missions like Ariel. His work helps bridge the gap between the precision of space-based telescopes and a spectral resolution achievable only from the ground.

So Matthea, I think it would be great to begin with your story. So what first drew you into astronomy and then how did you end up at spectroscopy? Is it all about the technology that drew you, the physics or just the idea that we can read the atmosphere of another planet from light that's streamed across our galaxy? So where does it all begin?

So I've always been curious about science in general and at some point I realized that I was really curious about astronomy, astrophysics and physics and trying to explain why things happen all around us, stuff like that. And during my third year of high school I started doing some physics experiments during a lab at the high school. was like, okay, this is my... The things that I have to do in my life is physics instead of like, for example, becoming a doctor, a real one. I became a doctor eventually. I mean, yes, I know. But the ones that you can call when you have an emergency, like it's a life or death situation, you won't like calling me probably.

Hey, hey, hang on. We are all real doctors here. We will not have that talk.

Wait a minute! Don't take that away from us.

Yeah. Yeah, I mean, you know, we can all we can do is soothe people with tales of the stars as they die Like that's that's where our use comes in. We can't save their life But we can keep them calm

Yeah, exactly.

Hahaha Come on, let's be honest, there are very worse ways for getting away, right? For dying.

Yeah, I understand, just don't ask me to save any life and it's fine. So decided to become a scientist and I started studying in Palermo physics for the bachelor degree and then I moved to Milan because I wanted to become an astrophysicist and I wanted to do a new experience in my life so I moved to Milan and I started studying cosmology.

Yeah. No, yeah.

which was really nice, but I kind of felt that it wasn't the things that I want to do later. And so I went back in Palermo, which is my hometown, studying again exoplanets because my Bachelor of Thesis was on exoplanets and starting this time with... Atmospheres and I think that I really liked back in the days as still nowadays the fact to try to assess What is and what is not in the atmosphere of an extra planet? Like what are the molecules or the atomic species that are in the in the atmosphere? Sometimes it seems like easy to do or just okay you once you acknowledge that it's done but still it's something that I really like. It combines several aspects of being a researcher that I like, like for example analyzing data but also planning observations, trying to understand which target you want to observe and why, and also observe directly several facilities. So this was the reason why I started studying exoplanetary atmospheres.

Hmm.

The high-resolution spectroscopy actually happened because in Palermo, within an Italian collaboration, there is CAPS, we have the possibility to work with the Telescopio Nazionale Galileo in La Palma, with ARPS North, the two-in-one ARPS instrument, and then of course also to work with Espresso along with other... low resolution instruments such as aerial missions that will be launched. So I started with high resolution side and I'm trying to move a little bit to the low one but the high resolution at this point is deeply in my heart so I really like it.

Yeah. So really, it's all about the travel, right? Going to La Palma and going, you know, all to all these different places. That's...

You won't say travel when you have to move from Palermo to anywhere else in Europe. It's always like two or three flights to go anywhere. consider that when I go to La Palma to observe, it's like 15 hours of traveling, then spending a night at the sea level, and then the next day going up observing, then everything back once you have to come back.

Yeah Mmm.

but often without sleeping the night. Really not about the travel. Maybe about the landscapes, but not the travel.

that's dedication. That's sh-

Yeah. Yeah.

Mattia, about the highest pollution spectroscopy that just happened in your life, can you walk us through what it is, how it works and what can tell us about exoplanets?

Okay, so I'll try. So spectroscopy is the study of the light coming from a source dividing it according to its wavelength, its energy, everything you want to call it. So you split the lights like the water vapor do. is the rainbow when the rainbow happens and so the same things apply to the study of stars. So you observe a star, you have some cool instrument like for example a spectrograph that splits the light and allows you to see what happens, what really happens in the star, let's say in the star which is the thing that we observe. So you can see that if you observe a star there are some markers in its spectrum which are to the elements, the atomic species and the molecular ones that are in its atmosphere, which we call photosphere. And you can do the same with an exoplanet. It's just slightly different because what happens is that when the planet transits in front of its own star, part of the starlight is scattered, so the photons interact with the species that are in the atmospheres of the planets, allowing us to see that in the spectrum some part of the spectrum is missing or has what we call an absorption feature, so you see that part of the stellar light has been absorbed by something and this something is something that is in the atmosphere of the planets, like in my case mostly atomic species because I work in the visible... visible band with arps, with half snort. So you can say okay now we are missing something here, it should be, we know from hearth lab that there should be a line of let's say hyron here, so maybe in the planet we have some hyron and...

We of course started to do this with the star and kinda everything, I don't wanna say star, but Palermo for example is a place where spectroscopy, stellar spectroscopy kinda started in the first society of spectroscopy. was founded from people in Palermo. There was a seminar today at the Astronomical Observatory talking about this, come on already.

Mmm. Yeah.

That's the same thing that you do for the star, you can do it for the planet as well, but you need the stellar light, because the planet does not have its own light, it's too faint. So we use the star, we can do this, we wait for the planet to in front of the stars and the atmosphere filters its radiation and we study it. least this is the Transmission Spectroscopy, to be clear, that is what I usually do.

Mmm.

gonna say anything about emission because it's really not my field.

No, that's fair. So you do a lot with high resolution spectroscopy. So I guess that means that's lots and lots of detail in the spectra, lots of fine wavelengths.

Exactly, so the resolution depends on the ability of your instrument to split the light into narrow or wider. channels, say. you can have something more detailed, like you were saying, with high resolution spectroscopy, where you are able to see and distinguish individual lines, like for example the ones that we can say this is iron. While of course if you go to lower resolutions, the line starts to blend all together and you are no more able to distinguish all of them, at least all of them, maybe the biggest one, yes, but not all of them altogether. And you start telling about bands more than lines. And of course, if you are able to study an individual line and you have more details, you can understand more about what you are investigating, thing that you can acknowledge from studying a low resolution spectrum, for example.

So why bother doing the low resolution broadband if like all of the information is in high resolution, like why bother?

Generally, say nowadays, low resolution and high resolution can refer to ground-based instrumentations and... space missions because from the ground you can build enormous facilities where you can put your spectrograph, high-resolution spectroscopy needs that instruments have to be really stable, you don't have to have any source of noise that may break your spectrum, that may contaminate your spectrum. While the low resolution is less sensible to these and requires smaller instruments and smaller mirrors, smaller telescopes to collect the light. usually nowadays bigger telescopes like the ones that we have like the Telescopio Nazionale Galileo with ARPS North or the ones in Chile with Espresso and ARPS are giant telescopes collecting a lot of lights with very stable foundations where you can put an high-resolution spectrograph, while low resolution is performed by space mission like for example HST, JWST, also aerial will be a low resolution mission. it's more something like an engineering problem to build an high-resolution facility orbiting is not that easy it seems.

Yeah.

I mean I'm not an expert but it's what they keep telling me. We can't have high resolution spectroscopy from space.

Yep. So then I guess in space you can maybe survey more with the low resolution so then you know what to target with the high resolution. Is that the idea?

Well, mean, the two techniques are kind of complementary because low resolution also allows you to do different things. For example, you can focus on a wider range of wavelengths and you can have what we call a continuum. So you can see the true level of the stellar flux that you receive while on high resolution usually you focus on a narrower region and you are not able to know what is happening globally and in the continuum. More important, most important, if you are on space, you do not have the Earth's atmosphere, which can be a problem, because the Earth's atmosphere has the stellar one and the planetary one as well.

Mmm.

do absorb light. And so what happens is that you also have to account for your own atmosphere while you are studying the other ones. And it can be challenging. I think that when I started my PhD, this was a that seems to be really bad. then, especially at high resolution, I have to say that nowadays, focusing on individual lines, we are getting

Yep. Mm-hmm. Hmm.

better avoiding the Earth's But of course we are still missing something and of course you have a lot of other pros observing from space. You do not have to wait for night for example to observe something like that. Different sides.

Mm-hmm.

And I also guess you may have some other, I'm going to say coms, least complications from observing from Earth, right? Because, true, you have your own atmospheres, but there are also other challenges, like telluric absorption, the weather which is changing, the gravity. How do you handle this in high-resolution spectroscopy from the ground?

So yes, of course there are some major problems related to planning the observation and then hoping of course that that night the weather will be nice and you will not have to put everything into the bin because some cloud decided that there was its moment to shine, let's say. Of course in the analysis you can, let's start from planning the observation, if you plan the observation you can try to mitigate these

Mmm. Yeah Yeah.

Mm-hmm.

effects, trying to repeat, to schedule more observations of the same target, to be sure that at least once the weather will be nice and you can try to model better the atmosphere above the place where you are observing and we are kind of nice doing this. We are getting good. Of course when you analyze the data you work with what you have at some point so you can correct for the atmospheric absorptions, the ludic lines. There are a lot of tools that do that. Again, we're getting good. And that's not a problem. If there is a cloud or anything else, some failure in the instrumentation, is really common. Really, I mean, not really common, but it can happen sometimes things that do not work or the automatic pipelines fail and you have to reduce again all your data. It's just... trying to see where the problem is and trying to get better fixing it. No tricks regarding this. Model your own atmospheres before studying the other ones. That's the first thing you have to learn. I think that one thing that we usually discuss with my colleagues is try to not overestimate and over... your data. You have what you have, try to get what you can get from your data without trying to squeeze them. don't know if you say this in English.

Mm-hmm. Yeah. Yeah. Yeah, yeah.

Yeah, was the Murphy load, right? If you torture the data long enough, they will confess anything.

yeah? I really hope so.

Yeah, yeah, yeah. So how do you model the atmosphere when the atmosphere is continually changing, right? It's not even on a night by night basis, but every few minutes, it's different to the minutes before.

Yes, of course you have to be time dependent in this case, but thing is that when you start an astronomical observation, you record all the parameters regarding what is happening in that moment. So you know the aim as to how much of atmosphere you have above you and you collect humidity and all of these other important... to model your atmosphere. since you know them point by point, let's say spectrum by spectrum, you can say, I have a tool that do model the Earth atmosphere and I can model the atmosphere in this condition and I can do it for all the conditions that I have in a night. So, the telluric contamination, the Earth spectrum evolves with your spectrum.

Mm.

Basically, that's it. It's not something that I personally do. Usually I think that these codes, these tools that study the Earth's atmosphere are developed by people focusing on our own planet while I like to look for other ones, as you can see.

So are like machine learning technologies and like AI, AI is always an interesting phrase to bring up because some people hate it and some people love it but are they changing the landscape? Are they helping with modeling the atmosphere, reducing the data, not you know overworking the data, things like that.

Regarding the modeling the Earth atmosphere, saw something recently with machine learning, but I think that the tools we have, the analytical tools that we have at this moment, works really good. For the exoplanet atmospheres, yes, there is a lot of work that people are doing for using machine learning. I'm not pretty sure about artificial intelligence, but for sure machine learning within the Ariel Consortium there is a... a lot of people working on that. So my experience, which Lorenzo knows really well about employing machine learning to fit Spectra, is that I'm not really sure that he's able to do it right now. It needs a little bit more of training. Will it be the future?

Yeah

Who knows? I'm not so sure. So they did not convince me a lot till now, but I'm really, really, really happy to learn and to see if machine learning can do the work that, of course, one single person, if you analyze targets individually, and of course you are putting all yourself doing this, it's different from something that a machine, let's say...

Nyeh heh heh. Mmm.

network is doing, a neural code is doing, something like that of course. But then again, for example for Ariel, we will not be able to analyze 1000 atmospheres all by ourselves. So yeah, we're gonna need it. It's just a matter of training them with what we did right now.

Yeah. Yeah, so you're need the help of the machines.

I chopped Lorenzo in the face!

Hmm

no, the rest are so happy. what you can't see dear listener is that Lorenzo is... Lorenzo is giving Matija the eyes like the evil eyes

He doesn't want to work with me anymore. Yeah, but let's be honest, Lorenzo talks with you.

You Mattia knows that I also work with machine learning on exoplanet. So I was like, I have a lot to say about that, but...

Yeah, I don't know, but I have to say, Lorenzo taught me to analyze some data and then we analyzed the same data with machine learning and it wasn't working, so up to this is a...

I have a lot to say about that, about this topic, but instead, back the ball to Mattias' garden and I will ask him, what about the location where we put all these huge telescopes? Because building telescopes that big that can work with high-solution spectroscopy, it's a huge effort. It's not only about money, and they cost a lot of money, it's also about people.

You

and time developed and hopes for the result. So you really need to put your telescope in a place where you can... Well, but the weight is not changing that much maybe, right? Can you elaborate a little on this?

Yes, of course. So let me start again from what I heard in the seminary that we have today at our Astronomical Observatory. The Astronomical Observatory of Palermo is one of the, I think it's the only one in Italy, along with Milan one, that is built in the city center. And of course you understand that at some point where they started with the lights in the city and stuff like that, the astronomical observatory is not good enough, can't stay in the city center, we need to move outside of the city center. And for the big facilities is the same, we build these facilities in place without... illuminations without any contamination from the the light and also with stable weather conditions like for example Chile where we have in English is Andes right I'm sorry I realize that I do not know how to say Andes in English. Andes yes I'm sorry.

Er, Andes. Like, so we have this joke in English which is like, er, where are the Andes? And like people say Chile but it's like you go, no, they're at the end of my armies. Like, arms. it's good!

Yeah, okay... You can cut it, right? Sounds good, okay, I'm not here to judge. Okay, so hand is yes. Yeah, English humor...

No, no, that's saying in. That was saying in.

And this people is English humor.

Usually I love English humor this time. No, I'm joking, was good. And so we built these, and these are not only for bad English humor jokes, but they are good for, a good place for building instruments for some sort of geographical conditions. They have stable weather, low levels of humidity. And of course there is also

you

the altitude of the Andes is helping us and that's the reason why the other instrumentations have been built on facilities that are high in altitude like for example the Canary Islands or some other facilities all around. you understand that Palermo's observatory on sea level in the city center is not good for nowadays science.

No. Yeah, I could imagine how it might be a problem, you know, just even you think about living in a town and city and just trying to use a pair of binoculars or a small telescope, you know, let alone trying to detect the light from an atmosphere of an exoplanet that's hundreds of light years away.

No, you won't see anything.

No, we collect some transits, are able to detect some planet transiting, so you can see that, for example, if you observe the star and the planets pass in front of the star, there is a decrease of the flux that you are collecting, because part of the stellar disk is obscured by the planet. And we can do this from here, but of course we can't... obtain the high-resolution data that we are able to obtain in huge facilities with less light contamination and way better conditions from humidity, temperature and stuff like that, of course.

Mmm. Yeah. Yeah.

About the instruments that you use, harps, espresso and in-gaps, where are they located?

So Arps North and Geno B are two instruments that are in the Telescopio Nazionale Galileo that is located in La Palma, Canary Islands, so the telescope is Italian, but has been built in La Palma because in the Canary Islands. Yeah, kind of.

Mm-hmm.

We know where to go for good weather and vacations.

Right, you say this, you say this, I went on a cruise in March and it was like to those islands and they get about five days rain a year, right? And for my cruise, we're all on my cruise. Like every single one, it was just raining like the entire time. Like you could not make it up. So I challenge your good weather.

Okay. about those five days? No, no, no.

Yeah.

You... You... You run away from the UK weather, from the rain from the UK and just jump into the rain of Canary Islands? gosh.

What I mean?

Yeah, basically I just pulled the clouds with me, they just followed the cruise ship and they were like, no Jen, you will not have sunshine.

Hahaha

The nice thing about building telescopes above a mountain is that usually the clouds are below. At least some of the clouds, not all of them, some of the clouds are below, so you can see them and enjoy the clouds without being worried of losing all the nights of observations. That's a nice pro.

That's Yeah. Mm, that's fair, yep. So with,

and

I'm sorry, I didn't finish the answer. Yeah, I remember. ARPS North and Gero B are installed mounted at the Telescopio Nazionale in La Palma, Canada Islands, while Espresso and ARPS, the twin of ARPS North, are both in Chile. One in La Silla, ARPS is in La Silla, and at the 3.6 meter telescope, while Espresso is in Paranal, at the VLD.

No, carry on. So of all these telescopes and instruments that you use, do you have like a favorite discovery or a favorite object that you've looked at with them?

Yes, I do. So, the first planet I started working with was Celt 9b. And Celt 9b is still my favorite planet because it is the hottest planet known. And it has a temperature. Hot is 4000 K, which means that it is hotter than several stars in the universe.

how hot is hot? Yeah, I was just thinking like 4000 Kelvin is like around about the temperature of sunspots on the surface of the Sun, right? It's around that. That's astonishing that there's a planet as hot as those.

Yes, it's other than most of the atmosphere. So if the most of the stars are type stars, Kelt 9b is other than most of the stars.

And that's these these red dwarf stars. So why is it so hot?

Exactly. So. The way we compute temperature is related to the stellar parameters and the distance of the planet from the star. So we do not actually know its temperature because we went there and we measured that. Of course, we compute what is called the equilibrium temperature and we assume that the planet has this temperature because it is located at some distance from the star and the star has its own temperature. And so an amount of light, certain amount of light arrives

Mm-hmm.

to the planet and then this irradiation causes that temperature. So the reason why it is so hot is because it's so close to its star. We are talking about an A-type star, so the star is pretty hot itself with 10,000 Kelvin temperature and this planet is located at one-tenth of the distance of Mercury from the Sun.

Pretty hot indeed.

So Mercury is the closest planet in the Kena and the star is a giant star. It has two point something the radius of the sun. So huge star, the planet is huge because it's an ultra-altitude Jupiter is larger than Jupiter both in radius and in mass and the reason why.

my goodness.

is basically surfing on the star.

Yeah. Yeah. And is it sort of puffed up because it's so close?

So the being puff depends on the mass of the planet, not only on the closeness to the star, because if the planet is massive enough to stay, let's say, compact to have a larger surface gravity that can retain all the gases surrounding it or the outer layer of gas, it's not puffy. So I won't say that the Kelt 90 is a puffy planet because it has a...

Okay, yeah. because it's massive.

Yes, it's massive, like 2.8 Jupiter masses, so it's really massive and it still has an extended atmosphere, mostly because the star is so close and it's a hot star that keeps irradiating the planet. But still, it's not what we usually call puffy from this point of view.

Okay. Okay.

At what point a system like this cannot, we can stop calling it a Python system and start calling it a binary system.

Hahaha

No.

A lot of people... So I think that the point is that everyone wants to get to Earth-like planets and so the big ones, the giant gaseous ones, close to the star, are always the bad planets, while the ones small, similar to hers, are the nice ones. No, I do not agree with you, Lorenzo. It's better to have bigger planets and hotter planets. But yeah...

you

There are some, it happens that objects like that with large temperatures and close to the star maybe is cheap for... binary system, but when you collect the spectra you can clearly see that the two are not two stars. You will see two different spectra while it's not the case. They are just the best thing that we have. The Hultral Jupiter.

Yeah. And so looking to the future, what do you think telescopes like the ELT and things like that are gonna impact, you know, the studies of these ultra-massive Jupiters and also, you know, the small planets which you're not too keen on, but you know, what do you think?

So the reason why we're not sticking on the small planets is because at this point we're good analyzing the big one and we are still not good enough analyzing the small ones. we should focus at least... This is what I do. I mean, not everyone should do the same, but I want more to focus on the ones that are large enough to be analyzed right now that have a signal in order to corroborate our analysis, our pipelines to be able, once we're going to have the next generation of instruments, to know what to do with the spectra of smaller planets. Because ELT, for example, will help us a lot with this huge size 30 meter diameter. But still, if you do not know what to do once you collect the light and you have the spectra, you can have a giant telescope and a wonderful spectrograph, but you have to be ready for when it comes. It's the same for what we did. Please.

Okay so it's like yeah so sort of right now you think it's it's all about study the big ones because the signals are stronger they're easier to understand hone the skills refine the knowledge and then when these big telescopes come online that's then when we can get into the the super earth's earth sized sort of worlds things like that based on the knowledge gained from learning how to analyse planets through studying the giant ones.

Well, mean, this is what I want to do right now, is that we try to focus on smaller planets, but... Unfortunately, the problem with smaller planets is that you are able to detect them around smaller stars. Otherwise, with the detection methods that we have, we are not able, so there is this selection effect. You have small planets, but only around small stars. And small stars are usually affected by stellar activity, which can... pretty much mimic all the things that we are able to observe in an exoplanetary atmosphere. And you need to collect a lot of spectra, lot of transits, lot of light to be able to fully analyze them. it's just not that I do not want to analyze them, of course. Analyzing smaller planets, it's what you need to start thinking about finding biotracers, for example, or trying to see if there is life anywhere else, or at least signs of that.

No, no.

But right now I'm working on refining the analysis that we have, trying to see if we can...

Mm-hmm.

develop some other ones to be able so when the ELT will be ready and observing we will need to collect let's say one spectrum instead of collecting 10 and so it will be we will be able to fully focus on smaller planets.

Okay, yeah.

Yeah.

And when ELT will be ready, available, ELT or all these huge facilities that, as you said, will collect more light, do you really have an idea of what are the answers that it can give us? mean, to which questions they can answer for us about, I don't know, pattern deformation or you say you measure habitability, for example, right?

Yes, this is not strictly my field, so I usually perform the analysis of the observations of the data and then ask for the help of some theoretical astronomer. Sorry? No, no, no, it's fine.

I can cut the question out if you do. Ok, if it's fine then take a step and start again.

Okay, so nice question, of course, we do not know what we will see, but we can start thinking what to expect. That's for sure. at least from my experience, for example, the single line analysis in the atmospheres of ultra-autotrumpeters. If during the time that we build these instruments, we, for example, identify a line or a feature in a spectrum that can be linked with habitability, with the presence of life, what we call a biosignature, At this point we can try to look for it. Of course, I'm not going to look for a biosignature on the Kelt 9b planet which is older than stars. But we can start thinking about doing that on planets that are more similar to the Earth. So we can try to do this. For example, if we will be able to distinguish among all the noise...

Yeah.

a feature, an individual feature that will tell us, yes, here we have something that reminds us of what we see on earth. We can try to think about life, we can try to think about everything that we want. I think that I will start looking, starting investigating them, for sure.

with the ELT, yeah, so it's like, the big questions around habitability for ground-based observations, you need that big telescope.

Yeah, I think so. I think that talking about beatability, talking about biomarkers right now, with the resolution that we have right now, is kinda... I mean, it's not feasible, at least from my point of view right now. You can try to feed some molecules in the atmosphere, also the resolution spectrum, saying, yes, this is a biomarker, we can see these... But I feel that we do not have the instruments able to do this right now. But that we are going to have them. The problem is that someone has to tell us what to look for. Because if I work on refining pipelines, someone has to work on identifying biomarkers and what we have to observe and tell us where to look for it.

Yeah. Yeah, they're coming. Yeah, yeah, that's true. That's where the modelers come in. Yeah.

Yeah. Yeah, so I think before we finish, we're gonna ask you our signature question. It's always an interesting one. And it is, if you could choose a celestial body, so it's a planet, a star, something like that, that represents you, what is it and why?

Oh-ho!

Okay. So before starting my diet a few weeks ago I would have said a black hole.

I know how you feel because I've been on like two back-to-back trips one of them was a cruise and You know five courses available at buffets. It's just it's not good

Yeah, I understand. I'm a black hole for sure during conferences and coffee breaks and stuff like that, honestly. But, I don't know, that's a tough one. Honestly, it's ice 2D planets, but I do like the stars, because it's what we really have to investigate planets. You can't study the planet without having...

You

Yeah. Yeah.

a And so I would say yes, a star. Not a specific one. A bright, a hot one, yes. A red one, maybe, yes. Just because I like the color. But just to not say black hole. But only because I'm on a diet right now. That's it. I can't. I'm just wearing black. But really, I really want to be able to do this.

Yeah. Yeah. Yeah. Yeah. Yeah.

So you can't, you can't be a black hole.

It's not possible right now.

Mattia, thank you. Thank you for joining us, thank you for being here. Thank you for bringing us closer to the art and precision of spectroscopy and telling us how we can investigate the huge giant, mostly, with the amazing telescopes that we built here on Earth.

And thanks to all of you for listening. Join us next time as we look further into the cosmos and meet the people transforming starlight into discovery.

Thank you so much.