= Exoplanet direct imaging
= Directly imaged exoplanet
{synonym}
<Exoplanet direct imaging> separates planetary light from the host <star>'s light on the sky. The two central obstacles are small angular separation and a large brightness contrast. <Diffraction> spreads stellar light into the surrounding image, and imperfect optics add structure that can resemble or hide a faint companion. <Adaptive optics> reduces blurring from the terrestrial <atmosphere>, improving the concentration and stability of the image.
Young giant <planets> on wide <orbits> are favourable targets because their intrinsic <thermal radiation> can be substantial. Measuring their light at several <wavelengths> constrains the <exoplanet atmosphere>; repeated positions trace the <orbit>. Brightness alone does not directly measure <mass>: converting it into <mass> requires an age and an evolutionary cooling model. <Doppler spectroscopy> or orbital dynamics can supply independent constraints.
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