On October 15, 2001, an
extrasolar planet was found orbiting the star.
Pi Mensae b is one of the most massive planets ever discovered, and has a very
eccentric orbit that takes approximately to complete. Because of its eccentricity, and being a massive
brown dwarf that passes through the
habitable zone, it would have disrupted the orbits of any Earth-like planets, and possibly thrown them into the star, or out into the
interstellar medium. Incorporating more accurate
Hipparcos data yields a mass range for the companion to be anywhere from 10.27 to 29.9 times that
of Jupiter, confirming its substellar nature with the upper limit of mass putting it in the
brown dwarf range. In 2020, the true mass of Pi Mensae b was measured to be via
astrometry. This was confirmed two days later, where the attention was called that the system is amenable for future planet atmospheric studies. Planet
c likely formed on a wide orbit, and then migrated inward under the gravitational influence of the planet or
brown dwarf b. It is likely to retain a portion of primordial, highly volatile atmosphere. In 2022, the discovery by the
radial velocity method of a third planet, Pi Mensae d, on a 125-day orbit was announced. Another 2022 study did not confirm this planet, but a 2023 study did detect it. ==See also==