The goal of Arago is to follow the cycle of matter, and therefore the entire life of stars and planets from their
formation from interstellar gas and grains to their death and feedback into the interstellar medium (ISM). During the
formation and throughout the life of stars and planets, a few key basic astrophysical properties, especially magnetic
fields, stellar winds, rotation, and binarity, influence their dynamics, and thus fundamentally impact their evolution.
The associated processes directly affect the internal structure of stars, the dynamics, and the immediate circumstellar
environment. They consequently drive stellar evolution, but also define the environments of planets, thereby
influencing the formation and fate of planets surrounding the stars. Arago will allow us to obtain, for the first time, a
full picture of the 3D dynamical environment of stars and their interactions with planets, and explore the conditions
for the emergence of life on exoplanets.
Mission: Arago is a candidate for ESA M7.
It is prepared by a consortium of about 250 scientists in 22 countries. Arago will observe all types of stars with a
typical magnitude between V=3 and 10. Observations will consist both in large surveys of thousands stars and in
detailed 3D mapping of 60 carefully chosen stars. If selected by ESA, Arago will be launched in 2037 at the L2
point, and the total nominal lifetime of the mission is 3 years.
Instrument: Arago consists of a 1-meter
Cassegrain telescope, equipped with a single polarimeter feeding two classical high-resolution echelle spectrographs
working in the UV [119-320] nm and visible [355-888] nm spectral range. The modulator is composed of a rotating stack
of plates followed by a polarizing beam-splitter, allowing users to measure the full Stokes (IQUV) spectrum. Arago
is equipped with CMOS sensors.