The Astrophysical Journal Letters (Jan 2024)

The MIRI Exoplanets Orbiting White dwarfs (MEOW) Survey: Mid-infrared Excess Reveals a Giant Planet Candidate around a Nearby White Dwarf

  • Mary Anne Limbach,
  • Andrew Vanderburg,
  • Alexander Venner,
  • Simon Blouin,
  • Kevin B. Stevenson,
  • Ryan J. MacDonald,
  • Sydney Jenkins,
  • Rachel Bowens-Rubin,
  • Melinda Soares-Furtado,
  • Caroline Morley,
  • Markus Janson,
  • John Debes,
  • Siyi Xu,
  • Evangelia Kleisioti,
  • Matthew Kenworthy,
  • Paul Butler,
  • Jeffrey D. Crane,
  • Dave Osip,
  • Stephen Shectman,
  • Johanna Teske

DOI
https://doi.org/10.3847/2041-8213/ad74ed
Journal volume & issue
Vol. 973, no. 1
p. L11

Abstract

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The MIRI Exoplanets Orbiting White dwarfs survey is a cycle 2 JWST program to search for exoplanets around dozens of nearby white dwarfs via infrared excess and direct imaging. In this Letter, we present the detection of mid-infrared excess at 18 and 21 μ m toward the bright ( V = 11.4) metal-polluted white dwarf WD 0310–688. The source of the IR excess is almost certainly within the system; the probability of background contamination is <0.1%. While the IR excess could be due to an unprecedentedly small and cold debris disk, it is best explained by a ${3.0}_{-1.9}^{+5.5}$ M _Jup cold (248 ${}_{-61}^{+84}$ K) giant planet orbiting the white dwarf within the forbidden zone (the region where planets are expected to be destroyed during the star’s red giant phase). We constrain the source of the IR excess to an orbital separation of 0.1–2 au, marking the first discovery of a white dwarf planet candidate within this range of separations. WD 0310–688 is a young remnant of an A- or late B-type star, and at just 10.4 pc, it is now the closest white dwarf with a known planet candidate. Future JWST observations could distinguish the two scenarios by either detecting or ruling out spectral features indicative of a planet atmosphere.

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