ARIEL SCIENCE ADVISORY TEAM UK ACTIVITIES

ARIEL (the Atmospheric Remote-sensing Infrared Exoplanet Large-survey) has been selected by ESA as the next medium class science mission (M4), expected to be launched in 2028. The mission will be devoted to observing spectroscopically in the optical and infrared a large and diverse population of transiting exoplanets in our nearby Galactic neighborhood, opening a new discovery space in the field of extrasolar planets and enabling the understanding of the physics and chemistry of these far away worlds.

ARIEL is based on a 1 m class telescope feeding two instruments: a moderate resolution spectrometer covering the wavelengths from 1.95 to 7.8 microns; and a three channel photometer (which also acts as a fine guidance sensor) with bands between 0.5 and 1.2 microns combined with a low resolution spectrometer covering 1.2 to 1.95 microns. During its four years of operation from an L2 orbit, ARIEL will continuously observe exoplanets transiting their host star. The target sample will include rocky and gaseous planets around a range of host star types. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials and thus reveal their bulk and elemental composition (especially C, O, N, S, Si). Observations of these warm/hot exoplanets will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star.

The ARIEL Phase-B study is currently ongoing and will end in the autumn 2020. The adoption is expected in November 2020. This proposal will enable the UK science team, led by UCL and OU (Prof. Tinetti and Prof. Haswell, appointed members of the ESA-SAT) to complete the Phase B study, being adopted in 2020 and maintaining the scientific leadership in the ARIEL international consortium.

Industrial return - There are a number of items for which the UK ARIEL team is already engaged with UK industry teams. The items that are already within our planning are:
* Industrialisation and space qualification of tactical cooler compressors (e.g Hymatic, Exotec)
* One of our key goals is to get UK industry (e.g. Airbus, TAS-UK) as prime contractor for ARIEL or to provide a significant part of the spacecraft system

Discussions will continue in Phase B to iterate on possible workpackages for UK industry as a way to leverage UKSA investment in the payload in order to maximize the UK industrial return from the S/C contract.

Outreach - The discovery of over 4000 extrasolar planets in the last couple of decades is probably one of the most exciting developments of modern astronomy. It resonates enormously with a public that has already been shown to have high interest levels in the exploration of the diverse worlds of our own Solar System, and an insatiable hunger for news about space exploration. It directly addresses deep philosophical issues that concern our fellow citizens: what are other worlds like? how do they form and evolve? Are we alone in the universe?. So that means that public outreach that aims to engage our fellow citizens with the excitement of ARIEL and its science objectives will be at the forefront of our planning. An excellent way to engage and motivate the public is to provide access to data. The public will be invited to participate in the science exploitation of the ARIEL mission through access to data sets, taking advantage of the networks developed by very successful citizen science programs such as the Zooniverse/Planet Hunters team using Kepler data [Zooniverse website], and Solar Stormwatch [Solar Stormwatch website].

Attracting the Next Generation of Scientists, Engineers, forming future leaders - the UK future economy and competitiveness depends on strong science and engineering sectors. The promotion of observational and space sciences is crucial to inspire development of the next generation of scientists and engineers. Extrasolar planets are today one of the most trendy subjects, inspiring young people to take up the (physical) sciences in later studies and in their careers. The number of students choosing this field of research is increasing almost exponentially. The ARIEL team will work actively at promoting gender-balance in science and engineering, inspiring young female students to choose STEM subjects at A-level and higher education and to widen participation at universities from underrepresented communities.