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| A team of international researchers used state-of-the-art modelling techniques to extensively study the atmosphere of a ‘hot Jupiter’ found 150 lightyears from Earth. |
Fascinating new light could be shed
on the complex atmospheres of planets which orbit stars outside our own solar
system, thanks to pioneering new research.
A team of international researchers,
led by astrophysicists from the University of Exeter, Columbia University and
NASA Goddard Institute for Space Studies, used state-of -the-art modelling
techniques to extensively study the atmosphere of a 'hot Jupiter' found 150
lightyears from Earth.
The scientists adapted the
state-of-the art computer model used by the Met Office to study the Earth's
atmosphere to perform simulations of these exotic distant worlds that are the
size of Jupiter, but orbiting more closely to their parent star than Mercury
does to the Sun.
The results were compared to
observations carried out using the powerful Spitzer Space Telescope, probing
our understanding of the conditions within the atmospheres of these planets.
The research revealed results that
were largely consistent with existing observations, most notably around the
effect of heat transport in the upper atmospheres of the exoplanets where
extreme velocity winds carry heat so rapidly that the hottest part of the
atmosphere is shifted away from the closest point to the star, where it would
be expected to be.
However, the study also revealed
some intriguing discrepancies, including significant differences between the observed
and expected brightness of the hot Jupiter's `nightside' - or the hemisphere
facing away from the star.
The team are now calling on further
studies to be conducted to unlock the secrets of how these planets evolve in
such close proximity to their host.
Dr Nathan Mayne, Senior Lecturer in
Astrophysics at the University of Exeter and one of the authors of the study
said: "This research is not only important in developing our understanding
of this exotic class of planets, but also represents the first steps to
building a deeper understanding of how planetary atmospheres and climates work
across a range of conditions, including those more conducive to life.
"Additionally, over a longer
timescale, by keeping close connection between astrophysicists and climate
researchers, this programme will aid in the understanding of our own changing
climate."
The Met Office weather and climate
prediction model is one of the most advanced models of its kind. However, this
research applies this model to a planet with conditions far from that present
on Earth, with temperatures exceeding one thousand degrees and an atmosphere
spanning pressures orders of magnitude larger.
A key finding of this research
indicates that there is still no clear understanding of how the material that
is moving from the hot dayside of the planet onto the cold nightside both cools
and alters it chemical composition.
Additionally, the team found
intriguing hints that the deeper atmosphere, inaccessible to observations,
supports large-scale, slow moving circulations potentially altering the
temperature structure deep in the hot Jupiter's atmosphere.
Dr David S. Amundsen, formerly of
the University of Exeter and now at Columbia University and NASA Goddard
Institute for Space Studies in the USA, and lead author of the paper added:
"Models such as the UM uniquely allows us to study in great detail how the
atmospheres of these planets change depending on different factors such as
irradiation, composition and rotation. These models are becoming increasingly
important to understand the continuously improving observations that are now
starting to reveal the complex three-dimensional nature of these atmospheres."
"The UK Met Office GCM with a
sophisticated radiation scheme applied to the the Jupiter HD209458" is
published in Astronomy & Astrophysics and is available online.
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