Scientists have investigated the isotopic composition of one of the hottest gas giants, the exoplanet WASP-121b. Worlds like it are usually called hot Jupiters. However, scientists have given them another unofficial nickname — “roasted marshmallows”.

Research on a hot gas giant
Scientists from the School of Earth and Space Exploration at Arizona National University have implemented a program to roast marshmallows in space. No, they didn’t go crazy and spend the allocated funds on their fantasies. They’re just okay with their sense of humor, and we’re talking about the study of the exoplanet WASP-121b.
It is one of the hottest gas giants known to mankind. Scientists call such worlds hot Jupiters, and their unofficial nickname is “roasted marshmallows.” These are really very loose and hot objects, so it suits them quite well.
The GRating INfrared Spectrograph (IGRINS) on the Gemini South telescope helped to study WASP-121b in detail. It helped to determine the chemical composition of this “roasted marshmallow” and to figure out exactly where it formed.
What did the research show?
Planetary systems are formed from gas and dust disks. The latter have a clear structure: rock grains, water ice and frozen gases can be found only at certain distances from the luminary. Therefore, by examining the chemical composition of a planet with a spectroscope, we can find out where it formed.
This is usually not such a simple process, because you need observations from two telescopes and two spectrographs on them at once. One should work in visible light and trace solid materials, the second — in infrared light where the gaseous component is especially visible.
However, WASP-121b is so hot that even the metals on it are in a gaseous state in the atmosphere. So IGRINS alone was enough to investigate it. And its results revealed a surprising thing. The composition of this “roasted marshmallow” has significantly more silicates and metals than scientists expected.
To be more precise, for the area where WASP-121b is now, there aren’t many. However, scientists expected much more of what were once chunks of ice as part of the protoplanetary disk. It is believed that gas giants only form in places where there must be a lot of it. But this study challenges such perceptions. Which means new observations will have to be made in order to understand what is really going on.
According to phys.org