Up until the early 2000s, the only known planets were in our own region, the Solar System. They generally fall into two divisions: the small rocky planets in the Inner Solar System and the cold gaseous planets located in the outer part.
With the discovery of exoplanets, planets erupting stars in addition to the Sun, additional classes of planets were discovered and a new picture began to emerge. Our solar system is not normal at all.
For example, data from the Kepler mission have shown that large, gaseous exoplanets can move very close to their star – rather than far away from it, as is the case in our Solar System, causing them to reach temperatures above 1,000K (727 degrees). Celsius). Jupiters have been called “hot” or “very hot”. And while most other exoplanets are smaller, between the size of Neptune and Earth, we don’t know much about their content.
But how can there be hot, gaseous planets and be so close to their star? What kind of physical processes take place here? The answers to these questions have a profound effect on our understanding of solar system exoplanets and planets. In our recent study, published in Letters of the Astrophysical Journal, we have added another piece to the puzzle of planetary creation and evolution.
Kelt-9 b
The hottest known exoplanet to date is Kelt-9 b, discovered in 2016. Kelt-9 is orbiting a star twice as hot as our Sun, at a speed of ten so much closer than Mercury is moving around our star. It is a large gaseous exoplanet, with a radius 1.8 times higher than Jupiter and the temperature reaches 5,000K. For comparison, this is hotter than 80% of all the stars in the universe and a temperature similar to our Sun.
In fact, Jupiters are hot as a window into real physical and chemical processes. They offer an incredible opportunity to study physics in environmental conditions that are virtually impossible to reproduce on Earth. Studying them strengthens our understanding of chemical and thermal processes, atmospheric dynamics and cloud formation. Understanding their origins can help us develop models of planetary shape and evolution.
We are still struggling to explain how planets shape and how elements, such as water, have been delivered to our own Solar System. To find out, we need to learn more about exoplanet writings by observing their emotions.
Air monitoring
There are two main ways to study the exoplanet atmosphere. In motion mode, we can pick up stellar light that will filter through the exoplanet’s atmosphere as it passes in front of its star, exposing the fingerprints of any chemical elements that are present.
The other way to study a planet is during an “eclipse”, when it goes behind the host star. Planets also emit and reflect a small fraction of light, so by comparing the small changes in total light when the planet is hidden and visible, we can emit the light coming from the planet.
Both types of observation are performed at different waves or colors, and because chemical elements and fertilizers absorb and emit at specific waves, a spectrum (light can be broken down by a wave- wave) to produce fruit for the planet to find the shape of its feeling.
Mystery of Kelt-9 b
In our study, we used publicly available data, provided by the Hubble Space Telescope, to obtain the eclipse spectrum of this planet.
We then used open source software to detect the presence of molecules and found that there were plenty of metals (made from molecules). This finding is interesting because it was previously thought that these molecules would not be present at such extreme temperatures – they would be separated from each other in smaller compounds.
Subject to the strong gravitational pull from its host star, Kelt-9 b is “quickly locked”, meaning that the only face of the planet permanently faces the star. This results in a strong temperature difference between the day and night sides of the planet.
As the eclipse observations study the warmer side of the day, we suggested that the molecules studied could be slowed down by dynamic processes from the coldest regions, such as the nocturnal side or from the depth of the side -in the planet. These observations reveal that the atmosphere of these real worlds is governed by complex processes that are not properly understood.
Kelt-9 b is interesting because of its curved orbit around 80 degrees. This suggests a past, with possible catastrophes, which is also visible for many other planets of this class. It is very likely that this planet formed away from its parent star and that the crashes occurred when it moved inward towards the star.
This supports the theory that large planets tend to form away from their host star in proto-stellar discs – which cause solar systems – to capture gaseous and solid materials while they do. migrated towards their star.
But we do not know exactly how precise this is. It is therefore essential to identify the character of many of these worlds in order to determine different situations and better understand the history as a whole.
Future missions
Observatories, such as the Hubble Space Telescope, were not designed to study exoplanet atmospheres. The next generation of space telescope will have far superior capabilities and instruments, such as the James Webb Space Telescope and the Ariel mission, which are designed specifically for close monitoring of the exoplanet atmosphere. They allow us to answer many of the basic questions raised by Jupiter’s terribly hot-planet planet, but they don’t stop there.
This new generation of telescopes will also explore a sense of a small world, a region that conventional instruments struggle to reach. In particular, Ariel, which is slated to launch in 2029, will monitor around 1,000 exoplanets to address some of the most fundamental questions in exoplanet science.
Ariel will also be the first space mission to look in detail at the sensations of these worlds. It should finally tell us what these exoplanets are and how they were created and evolved. This will be a real turnaround.
Quentin Changeat is a Postdoctoral Research Fellow in Astronomy and Billy Edwards is a Project Scientist at the Twinkle Space Mission, Astronomy Research Fellow at University College London.
This article originally appeared on An Còmhradh.