TOI-4603 b is a gas giant exoplanet orbiting HD 245134, a F-type subgiant star located 731 light-years away, in the constellation of Taurus.

[4] NASA's Transiting Exoplanet Survey Satellite observed the host star TOI-4603 between September 16, 2021, and December 2, 2021.

[2] Afterwards, the group of astronomers led by Akanksha Khandelwal of the Physical Research Laboratory (PRL) in India, reported that a transit signal had been identified in the light curve of the star.

Radial velocity measurements taken with the PARAS and TRES[note 3] spectrographs confirmed the transit signal to be an exoplanet orbiting the star.

[1] [note 1] It is well suited for the study of the Rossiter–McLaughlin effect and helpful for measuring the projected stellar obliquity of planets.