Finding Planets Around White Dwarf Remnants of Massive Stars

Abstract

Planet frequency shows a strong positive correlation with host mass from the hydrogen-burning limit to M ~ 2Msun. No search has yet been conducted for planets of higher-mass hosts because all existing techniques are insensitive to these planets. We show that infrared observations of the white-dwarf (WD) remnants of massive stars 3Msun < M < 7Msun would be sensitive to these planets for reasons that are closely connected to the insensitivity of other methods. We identify 49 reasonably bright, young, massive WDs from the Palomar-Green survey and discuss methods for detecting planets and for distinguishing between planet and disk explanations for any excess flux observed. The young, bright, massive WD sample could be expanded by a factor 4-5 by surveying the remainder of the sky for bright UV-excess objects.