Stellar tidal-dissipation timescale and modified quality factor

Determine the tidal-decay timescale and effective modified stellar tidal quality factor for hot Jupiters as functions of planetary mass, orbital period, and host-star internal structure.

Background

The timescale on which stellar tides shrink a hot Jupiter’s orbit determines whether the planet can be engulfed during the host star’s main-sequence lifetime. The paper emphasizes that the effective modified tidal quality factor is commonly treated as fixed in observational work, even though tidal theory predicts dependence on planetary and stellar properties. The physical mechanisms governing stellar tidal dissipation therefore remain insufficiently constrained.

References

Nevertheless, the timescale of such tidal decay, or equivalently the (effective) ``modified tidal quality factor" of the star, $Q'*$, defined as the quality factor $Q\star$ divided by $2/3$ of the Love number $k_2$ \citep{goldreich1966solar}, remains highly uncertain due to our poor understanding of the tidal dissipation mechanisms within stars.

— Are Hot Jupiters Tidally Disrupted During Stellar Main Sequence?  (2608.12790 - Hu et al., 13 Aug 2026) in Section 1, Introduction