ARIEL mission to better understand exoplanet evolution gets green light

Oxford University are to play a key role in ARIEL, a new research mission to better understand the formation and evolution of exoplanets.

The project was chosen by the European Space Agency (ESA) from three academic proposals, with the final selection announced today, 20 March 2018.

The ARIEL mission is intended to answer fundamental questions about how planetary systems develop over time. Over the course of four years, the ARIEL spacecraft, will observe 1000 planets orbiting distant stars and marks the first large-scale survey of the chemistry of exoplanet atmospheres.

The instrument will have a meter-class mirror which will collect visible and infrared light from distant star systems. A spectrometer will spread this light into a ‘rainbow’ and extract the chemical fingerprints of gases in the planets’ atmospheres. A photometer and guidance system will then capture information on the presence on clouds in the atmospheres of the exoplanets and will allow the spacecraft to point to the target star with high stability and precision.

The ARIEL mission has been developed by a consortium of more than 60 institutes from 15 ESA member state countries, including UK, France, Italy, Poland, Spain, the Netherlands, Belgium, Austria, Denmark, Ireland, Hungary, Sweden, Czech Republic, Germany, Portugal, with an additional contribution from NASA in the USA currently under study. UK institutions have provided the leadership and planning for ARIEL, including UCL, STFC RAL Space, STFC UK ATC, Cardiff University and the University of Oxford.

Scientists from Oxford’s Department of Physics will support the optical performance testing of the instrument alongside RAL Space. The team also have a strong interest in the atmospheric science data that the mission will generate, and will channel that into future projects.

ARIEL’s Principal Investigator, Professor Giovanna Tinetti of UCL said: “Although we’ve now discovered around 3800 planets orbiting other stars, the nature of these exoplanets remains largely mysterious. ARIEL will study a statistically large sample of exoplanets to give us a truly representative picture of what these planets are like. This will enable us to answer questions about how the chemistry of a planet links to the environment in which it forms, and how its birth and evolution are affected by its parent star.”

Discussing the announcement, Dr Neil Bowles, ARIEL Co-Investigator and Associate Professor in the department of Physics at Oxford, said: ‘This is fantastic news. Our experience of observing and exploring our Solar System has shown that each time we get new data we have to alter our understanding of how planets “work" significantly. With ARIEL surveying a large number of exoplanet atmospheres it will be fascinating to see how this extends beyond our Solar System and help us to form some context of how other planetary systems compare.’

ARIEL is set to launch in 2028 and will take-off from Kourou in French Guiana. It will be positioned to monitor Lagrange Point 2 (L2), a gravitational balance point 1.5 million kilometres beyond the Earth’s orbit of the Sun. A location that both shields the spacecraft from the Sun and offers an optimum clear view of the whole sky to maximise the possible target exoplanets for observations.