Probing Exoplanets Around Massive Stars

Fraction of white dwarfs showing photospheric metals in our Hubble Space Telescope ultraviolet sample (orange) as a function of white dwarf mass (top x-axis label) and main-sequence progenitor mass (bottom x-axis label). The most massive white dwarfs exhibit significantly less metal pollution (from Ould Rouis et al. 2024).

In November 2024, a manuscript led by graduate student and BUWD member Lou Baya Ould Rouis (Ould Rouis, Hermes, Gaensicke et al. 2024) was accepting which showed that the most massive white dwarfs (>0.8 solar masses) show metal pollution significantly less frequently than more normal-mass white dwarfs. Specifically, just 11% of white dwarfs that begin their lives as stars >3.5 solar masses on the main sequence show metals from remnant planetary systems, while 44% of white dwarfs that begin their lives as stars <2 solar masses show metals. We have also shown that mergers are unlikely to be the main explanation for this discrepancy. The findings likely have implications for planet formation and/or survival around massive stars on the main sequence which are hard to search for exoplanets using traditional techniques. The manuscript has been accepted in The Astrophysical Journal.

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