 Kappa Corona Borealis used to be a much hotter class A star,showing that such stars -- which are more massive than the Sun andfrequently have surrounding debris disks -- also have real planetsto go along with them.THE PLANETThe upper circle shows the location of the class K subgiant KappaCoronae Borealis (in the constellationCoronaBorealis). The planet orbits Kappa Coronae Borealis in 1191days (3.26 years), averaging 2.7 Astronomical Units from the star,which would place it nicely within our asteroid belt 1.8 timesfarther than Mars is from the Sun. However, a modest eccentricityof 0.19 makes the planet sweep from as far as 3.2 AU to Kappa to asclose as 2.2, a range of a full Astronomical Unit, which would makea fine mess of any asteroid belt that might ever have formed. Since we do not know the planet's orbital tilt, we can measure onlya lower limit to its mass, which is at least 1.8 timesthat of Jupiter.
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