ARIEL SCIENCE ADVISORY TEAM UK ACTIVITIES

ARIEL (the Atmospheric Remote-sensing Infrared Exoplanet Large-survey) has been selected by the European Space Agency (ESA) as the next medium class science mission (M4), expected to be launched in 2028. The mission will be devoted to performing spectroscopy, in which the optical and infrared light is spread into its component colours, or wavelengths to use the scientific term. Spectroscopy allows us to determine the chemicals present in an exoplanet atmosphere. ARIEL will observe a large and diverse population of exoplanets in our nearby Galactic neighborhood, revealing what they are made of, 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. It will travel to the second Lagrangian point of the Earth-Sun system, i.e. in the direction of Earth's shadow at a place where there is a special gravitationally stable point. This point is often abbreviated as "L2". During its four years of operation, ARIEL will continuously observe exoplanets passing across the face of 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 late 2020. Assuming the study finds no show-stopping problems, ARIEL is forseen to be adopted by ESA in November 2020. ARIEL is a UK-led mission, and the work we will do funded by this grant will help UK scientists to make sure the mission delivers the best possible new science. This proposal will enable the UK science team, led by UCL and OU: Prof. Tinetti and Prof. Haswell, the UK appointed members of the Science Advisory Team (ESA-SAT). They will complete the Phase B study, and maintain 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. Haswell is a Redcar Ambassador, and is developing a network of contacts on Teesside with the aim of promoting and invigorating the fledgling high-tech and space industry there. These contacts include the prime movers behind The Digital City (see https://thedigitalcity.com/about/). Teesside is currently economically deprived, but has a strong industrial heritage and a pool of under-utilised talent.

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. The Open University has recently launched a free course "An Introduction to Exoplanets" (https://www.open.edu/openlearn/science-maths-technology/introduction-exoplanets/content-section-overview?active-tab=description-tab) which was conceived and produced by Haswell as lead academic. This course provides a roughly GCSE-level introduction to the scientific field of ARIEL, including transit spectroscopy.


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 and racial balance in science and engineering, inspiring young female and BAME students to choose STEM subjects at A-level and higher education and to widen participation at universities from underrepresented communities. The Open University has an explicit widening participation remit, and a 50-year track record.