Subaru Telescope 2.0

Key Instruments > InfraRed Doppler (IRD)

InfraRed Doppler (IRD)

赤外線ドップラー装置 IRD InfraRed Doppler

InfraRed Doppler (IRD), which experienced the first light in 2018, is an infrared instrument used in the search for exoplanets (extrasolar planets). IRD is specialized for finding exoplanets with the Doppler method by detecting wobbles of a host star with an accuracy of 2 meters per second, corresponding to the speed of a human walk.

M-type stars (or M dwarfs) with a smaller mass than the Sun are abundant in the vicinity of our Solar System. They emit most energy in infrared rather than visible light and are preferred targets for IRD. The five-year extensive observing program “InfraRed Doppler Subaru Strategic Program (IRD-SSP)” has been ongoing since 2019, observing for 170 nights. This program aims to discover Earth-like planets orbiting low-mass faint stars utilizing the world’s best precision in velocity determination of IRD and the large aperture of the Subaru Telescope.

IRD is developed in collaboration with the Astrobiology Center (ABC) of the National Institutes of Natural Science (NINS), the University of Hawai`i, and others. ABC leads the operation and maintenance of the instrument.


Doppler method: detecting exoplanets by detecting velocity changes of a host star.

Infrared observations: searching Earth-like exoplanets around low-mass stars.