A Disintegrating Rocky Planet with Prominent Comet-like Tails around a Bright Star
Abstract We report the discovery of BD+05 4868 Ab, a transiting exoplanet orbiting a bright ( V = 10.16) K-dwarf (TIC 466376085) with a period of 1.27 days. Observations from NASA’s Transiting Exoplanet Survey Satellite reveal variable transit depths and asymmetric transit profiles that are characteristic of comet-like tails formed by dusty effluents emanating from a disintegrating planet. Unique to BD+05 4868 Ab is the presence of prominent dust tails in both the trailing and leading directions that contribute to the extinction of starlight from the host star. By fitting the observed transit profile and analytically modeling the drift of dust grains within both dust tails, we infer large grain sizes (∼1–10 μ m) and a mass-loss rate of 10 M ⊕ Gyr −1 , suggestive of a lunar-mass object with a disintegration timescale of only several Myr. The host star is probably older than the Sun and is accompanied by an M-dwarf companion at a projected physical separation of 130 au. The brightness of the host star, combined with the planet’s relatively deep transits (0.8%–2.0%), presents BD+05 4868 Ab as a prime target for compositional studies of rocky exoplanets and investigations into the nature of catastrophically evaporating planets.
Authors
- S. Rappaport (ORCID: https://orcid.org/0000-0003-3182-5569)
- Akihiko Fukui (ORCID: https://orcid.org/0000-0002-4909-5763)
- Cristilyn N. Watkins (ORCID: https://orcid.org/0000-0001-8621-6731)
- Katharine Hesse (ORCID: https://orcid.org/0000-0002-2135-9018)
- W. Fong (ORCID: https://orcid.org/0000-0003-0241-2757)
- Samuel W. Yee (ORCID: https://orcid.org/0000-0001-7961-3907)
- Karen A. Collins (ORCID: https://orcid.org/0000-0001-6588-9574)
- Emily A. Gilbert (ORCID: https://orcid.org/0000-0002-0388-8004)
- Sara Seager (ORCID: https://orcid.org/0000-0002-6892-6948)
- Richard P. Schwarz (ORCID: https://orcid.org/0000-0001-8227-1020)
- Andrew Vanderburg (ORCID: https://orcid.org/0000-0001-7246-5438)
- Khalid Barkaoui (ORCID: https://orcid.org/0000-0003-1464-9276)
- G. Ricker (ORCID: https://orcid.org/0000-0003-2058-6662)
- Jeroen Audenaert (ORCID: https://orcid.org/0000-0002-4371-3460)
- Avi Shporer (ORCID: https://orcid.org/0000-0002-1836-3120)
- Alex S. Polanski (ORCID: https://orcid.org/0000-0001-7047-8681)
- Daniel Muthukrishna (ORCID: https://orcid.org/0000-0002-5788-9280)
- David R. Ciardi (ORCID: https://orcid.org/0000-0002-5741-3047)
- Marc Hon (ORCID: https://orcid.org/0000-0003-2400-6960)
- Norio Narita (ORCID: https://orcid.org/0000-0001-8511-2981)
- G. Petitpas
- Joshua N. Winn (ORCID: https://orcid.org/0000-0002-4265-047X)
- Jack Haviland
- Ellie Hadjiyska Schmelzer (ORCID: https://orcid.org/0000-0002-4853-8075)
Institutions
- California Institute of Technology (US)
- Jet Propulsion Laboratory (US)
- University of Kansas (US)
- University of Liège (BE)
- Princeton University (US)
- Lowell Observatory (US)
- NASA Exoplanet Science Institute (US)
- Astrobiology Center (JP)
- Center for Astrophysics Harvard & Smithsonian (US)
- Instituto de Astrofísica de Canarias (ES)
- Tokyo Metropolitan Komaba High School (JP)
- American Institute of Aeronautics and Astronautics (US)
- Massachusetts Institute of Technology (US)
- The University of Tokyo (JP)
Publication Details
- Journal
- The Astrophysical Journal Letters
- Published
- 2025-04-22
- DOI
- https://doi.org/10.3847/2041-8213/adbf21
- Citations
- 5
- Primary Topic
- Astro and Planetary Science
- Type
- article
- Field-Weighted Citation Impact
- 5.77
Funders
- National Aeronautics and Space Administration
- Massachusetts Institute of Technology
- Heising-Simons Foundation
- Fonds De La Recherche Scientifique - FNRS