Roman could test how often planets survive white-dwarf evolution

Zifan Lin and Tansu Daylan modeled how the Nancy Grace Roman Space Telescope's Galactic Bulge Time Domain Survey could detect planets around white dwarfs. Roman is expected to observe thousands of these compact stellar remnants at 12.1-minute cadence. The authors simulated transits and phase curves across planet sizes, periods, host properties, and a synthetic Milky Way population for the survey's first three high-cadence seasons.

Crowding is the dominant constraint: source blending removes about 95 percent of the raw predicted yield. Their period-averaged effective survey contains roughly eight Jupiter-size opportunities, so an underlying occurrence rate near 12 percent would be needed for one expected detection; smaller planets are harder. Phase curves add at most about four percent to the transit yield. A null result could still limit close-in Jupiter-size planets around white dwarfs to below roughly 28 percent at 95 percent confidence. These are forecasts, not Roman observations or discovered planets.

Why it matters

White-dwarf systems test whether planets endure or reassemble after violent stellar evolution. Roman could finally move that question from a handful of objects toward population statistics.

What the source establishes

Verified unreviewed survey simulation submitted to the AAS journals. Prospective yield and null-result limits only; Roman has not begun science observations and no new planet is reported.