Rare-Earth metals in the atmosphere of a glowing-hot exoplanet

I’m Kevin Heng, I’m a theoretical astrophysicist,
who is interested in exoplanets, planets around other stars beyond our solar system. I’m currently a professor of astrophysics
at the University of Bern and the director of the Center for Space and Habitability. My name is Jens Hoeijmakers. I’m from the Netherlands but I have worked
at the Center for Space and Habitability at the University of Bern and the Observatory
of Geneva for a little over a year. My interest is the study of the atmospheres
of exoplanets, using very large telescopes that are spread out all over the world. What is special about the Exoplanet KELT-9b? KELT-9b is a very hot gas giant planet. You can imagen it as a planet that is somewhat
similar as Jupiter in our solar system. But it is located very close to its host star. And that itself is not necessarily special,
because we know of many planets that are like this. We call them hot Jupiters. But this planet is orbiting a particularly
hot star as well. And that means that it is the hottest exoplanet
that we know of exists today. What did you discover? So, what we have discovered in the atmosphere
of KELT-9b is that it contains, in gaseous forms, heavy metals, such as iron, titanium,
chromium and other heavy metals, that have never been observed in the atmosphere of a
planet before. In the atmosphere of KELT-9b we have detected
a number of heavy metals, and two of these are what we call rare-earth metals, Scandium
and Yttrium. And these have not been observed in the atmosphere
of any planet before. How did you make these discoveries? To study what the atmospheres of a planet
is made of, astronomers make use of a technique called spectroscopy. So, the light from the exoplanets system will
reach our telescope and the telescope, instead of making a picture, will feed the light into
the instrument called spectrograph and the spectrograph acts to disperse the light into
its individual colors, like a rainbow. Now this rainbow will tell us, how bright
the object is, at each of its individual colors. But the material that is present in the planet,
will absorb colors at very specific places. And for many atoms or species that can be
a very complicated pattern of colors that it absorbs. You can think of that as some sort of a finger
print. Every atom has its unique pattern of colors
or its unique finger print that it absorbs. By passing the light through a spectrograph
and seeing which colors it absorbs, we’ll be able to distinguish which elements are
present in the object, even if its many lightyears away. Why are these discoveries important? One of the reasons why are so interested,
almost obsessed with this technique is because it is very general. It makes us think of molecules and atoms as
finger prints of an exoplanet Once you accept that idea you can use it to search for anything
you want. In the case of KELT-9b we searched for metals,
but you can imagine that in the future, we could use it to search for biosignatures. So, signs of life in another exoplanet.

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