The Metis coronagraph

Metis is the coronagraph of the scientific payload of Solar Orbiter, the first mission of the European Space Agency program Cosmic Vision 2015-2025. Solar Orbiter has been conceived to explore for the first time the poles of the Sun and the circumsolar region. The spacecraft launch has taken place on February 10th, 2020.

Metis flight telescope after integration

The main Metis objective is the investigation of the global corona in polarized visible light and in ultraviolet light. In the ultraviolet band, the coronagraph obtains monochromatic images in the Lyman-α line, at 121.6 nm, emitted by the few neutral-hydrogen atoms surviving in the hot corona.

By simulating a solar eclipse, Metis observes the faint coronal light, at least one millionth dimmer than the disk light, in an annular zone 1.6°–2.9° wide, around the disk center. When Solar Orbiter is at its closest approach to the Sun, at the minimum perihelion of 0.28 AU (i.e., astronomical unit), the annular zone is within 1.7 and 3.1 R (solar radii) from disk center.

Metis field of view (grey area) at 0.29 AU from Sun center

Metis field of view (grey area) at 0.39 AU from Sun center

Futher information can be found in the Metis paper on the Solar Orbiter mission book.

The Metis experiment

The Metis experiment is an international collaboration led by the Italian National Institute for Astrophysics (INAF) and supported by the Italian Space Agency (ASI), involving several Universities in Italy and research institutes in the world.

The Italian scientific team of solar space physics, formed during the development and operations of SOHO/UVCS, is responsible for the Metis concept, optical design, on-ground calibration, and in-flight operations and calibration. The Metis project is funded by the Italian Space Agency (ASI) and by INAF.

Two significant international contributions are acknowledged. The Max Planck Institut für Sonnensystemforschung (MPS), in Göttingen, Germany, and the Astronomical Institute of the Science Academy (AIAS) of the Czech Republic, in Prague, contribute the detectors and the mirrors of the Metis coronagraph, respectively. The manufacture of the mirrors has been assigned to TopTec.

Metis is part of the scientific program coordinated by Barbara Negri, ASI Head of Exploration and Observation of the Universe. During Phases A to D, the Metis Program Manager of the Italian Space Agency is Marco Castronuovo, co-adiuvated by Alessandro Gabrielli and Roberto Bertacin. During Phase E the ASI Metis Program Manager and Project Scientist is Marco Stangalini.

Metis team acknowledges the fundamental support of the ESA Solar Orbiter Payload manager, Filippo Marliani, during the instrument development.