HD 190984 b (also known as HIP 99496 b) is an exoplanet which orbits the F-type main sequence star HD 190984, located approximately 486 light-years away in the constellation Pavo.
This planet has a minimum mass three times that of Jupiter and takes 13 years and four-and-a-half months to orbit the star at a semimajor axis of 5.5 AU with an eccentricity of 0.57.
Since this is a very long-period planet detected by the radial velocity method and this planet didn't complete its orbit during the continuous observations, the error range for orbital period is very large, at 4885 ± 1600 days or 13.37 ± 4.4 years.
So this planet will need more years of observations to better constrain the period and semimajor axis.
In 2023, the inclination and true mass of HD 190984 b were determined via astrometry, and its orbit was updated, finding a longer period and larger semi-major axis than previously estimated, although still with a large margin of error.