Rho Coronae Borealis
Rho Coronae Borealis is an old star hosting four planets, one of which was among the first exoplanets discovered (in 1997). At one point, astrometric data suggested that the true mass of Rho CrB b was much higher, making it a low-mass star rather than a planet. However, more recent work has ruled out stellar companions to this star, as well as detecting three more planets in the system.
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