Back to COPAINS. Let's return to HIP 29724 by way of HD 60584.
HD 60584 has proven an (?)accidental binary, F5V+F6V. CC1 is the closer to us at parallax 32.792 ± 0.035. This star weighs in at 1.352 ± 0.014 M⊙. The two stars are not gravitationally locked as far as the study can tell us but then, CC2 was only identified within this study so could be observed for a mere few years.
HD 60584 CC1 might have an orbiter 16.58 ± 0.15 AU. 0.028 M⊙ (29.316 Mj)... or maybe 0.008 ± 0.003 M⊙. Stellar age is 300-1700 My so tagged an even billion. Note that F stars of this mass simply can't live much longer than 1700 My, before redgianting. The imaging data wasn't the best. I shall assume the worst, that is 30 Mj.
By my maths 1415/r2 Jovian units of Pull go to the star; 30/(16.58-r)2 to the browndwarf. Let's put r at a habitable 2 AU. 707.5 Junits to the star; out to the dwarf 0.141 Junits at conjunction and 0.087 at opposition. 3.2e-4 total which is slightly more than the 2.1e-4 ratio Jupiter exerts on Mars, with the proviso that this putative planet hasn't had as much time.
Overall I think HD 60584 CC1 can maintain a habitable planet if there be Venuslikes beneath that orbit, keeping it in circularity. HIP 29724's 66 Mj "dwarf" at 6.3 AU seems a tougher sell, frankly. On the other side, HIP 21152's 1.442 M⊙ has its browndwarf at 18.28 AU, admittedly a slightly heavier 33.5 Mj.
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