TOI-1136 is a G-type main-sequence star away in the constellation of Draco. It is slightly smaller than the Sun and similar in mass and temperature, but is much younger, with an age of about 700 million years. It hosts a system of at least six, and possibly seven exoplanets.
Planetary system TOI-1136 was discovered to have six transiting planets in 2022 using the Transiting Exoplanet Survey Satellite (TESS), all orbiting closer to their star than Mercury is to the Sun. All of them are Neptune-sized or sub-Neptunes, and their masses have been measured using a combination of radial velocity and transit-timing variations, showing them to have low densities. The planets are in an orbital resonance, with period ratios near 3:2, 2:1, 3:2, 7:5, and 3:2.
A possible single transit of a seventh planet was also identified. This candidate planet would also be sub-Neptune-size planet, but its orbit is poorly constrained. If this is confirmed, it would make TOI-1136 one of the most populous known planetary systems.
See also HD 110067 Kepler-90 Kepler-385 TOI-178 TRAPPIST-1
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