exosatellite

An exosatellite (or exomoon or extrasolar satellite or moon) is a satellite/moon outside the solar system, e.g., orbiting an extra-solar planet. No exosatellite has been unequivocally identified, though there have been candidates. The proposed detection methods are essentially variations of the methods used to detect exoplanets:

• Direct imaging.
• Doppler spectroscopy of the host exoplanet.
• Gravitational microlensing.
• Pulsar timing.
• Transit method.
• Transit timing variations (TTV).
• Transit duration variations (TDV).

For example, a series of exoplanet transit light curves from the same planet might show occasional additional blocked light that suggests during those transits, a moon was positioned to block a little bit more of the host star's light.