Transit Timing of the White Dwarf-cold Jupiter System WD 1856+534

Le résumé fourni par la source

Abstract We present new transit-timing measurements for the white dwarf-cold Jupiter system WD 1856+534, extending the baseline of observations from 311 epochs to 1498 epochs. The planet is unlikely to have survived the host star’s red-giant phase at its present location and is likely too small for common envelope evolution to take place. As such, a plausible explanation for the short semimajor axis is that the exoplanet started out on a much larger orbit and then spiraled inward through high-eccentricity tidal migration (HETM). A past study found tentative evidence for orbital growth, which could have been interpreted as a residual effect of HETM, but we find the data are consistent with a constant-period model after adding 18 new transit measurements. We use the estimated period derivative P ̇ = 0.04 ± 0.43 ms yr −1 to place a lower limit on the planetary tidal quality factor of Q p ′ ≳ 3.1 × 1 0 6 , if the planet has not already achieved spin–orbit synchronization. We also test for the presence of companion planets in the system, which could have excited WD 1856 b onto an eccentric orbit via the Kozai–Lidov process, and ultimately rule out the presence of an additional planet with mass greater than 4.0 M J and period shorter than 1500 days. We find no evidence for nonzero eccentricity, with an upper limit of e ≲ 10 −2 . If the planet reached its current orbit through HETM, the low present-day eccentricity indicates that the migration process has now ceased, and any further orbital evolution, if any, will likely be governed by weak planetary tides.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.