The only inflated brown dwarf in an eclipsing white dwarf–brown dwarf binary: WD1032+011B
ABSTRACT Due to their short orbital periods and relatively high-flux ratios, irradiated brown dwarfs in binaries with white dwarfs offer better opportunities to study irradiated atmospheres than hot Jupiters, which have lower planet-to-star flux ratios. WD1032+011 is an eclipsing, tidally locked white dwarf–brown dwarf binary with a 9950 K white dwarf orbited by a 69.7 M$_{\text{Jup}}$ brown dwarf in a 0.09 d orbit. We present time-resolved Hubble Space Telescope Wide Field Camera 3 spectrophotometric data of WD1032+011. We isolate the phase-dependent spectra of WD1032+011B, finding a 210 K difference in brightness temperature between the dayside and nightside. The spectral type of the brown dwarf is identified as L1 peculiar, with atmospheric retrievals and comparison to field brown dwarfs showing evidence for a cloud-free atmosphere. The retrieved temperature of the dayside is 1748$^{+66}_{-67}$ K, with a nightside temperature of 1555$^{+76}_{-62}$ K, showing an irradiation-driven temperature contrast coupled with inefficient heat redistribution from the dayside to the nightside. The brown dwarf radius is inflated, likely due to the constant irradiation from the white dwarf, making it the only known inflated brown dwarf in an eclipsing white dwarf–brown dwarf binary.
Authors
- R. Amaro (ORCID: https://orcid.org/0000-0002-1546-9763)
- S. P. Littlefair (ORCID: https://orcid.org/0000-0001-7221-855X)
- Xianyu Tan (ORCID: https://orcid.org/0000-0003-2278-6932)
- S. L. Casewell (ORCID: https://orcid.org/0000-0003-2478-0120)
- Joshua D. Lothringer (ORCID: https://orcid.org/0000-0003-3667-8633)
- L. C. Mayorga (ORCID: https://orcid.org/0000-0002-4321-4581)
- Jenni R French (ORCID: https://orcid.org/0000-0003-0825-4876)
- Dániel Apai (ORCID: https://orcid.org/0000-0003-3714-5855)
- Ben W. P. Lew (ORCID: https://orcid.org/0000-0003-1487-6452)
- Mark S. Marley (ORCID: https://orcid.org/0000-0002-5251-2943)
- Vivien Parmentier (ORCID: https://orcid.org/0000-0001-9521-6258)
- Yifan Zhou (ORCID: https://orcid.org/0000-0003-2969-6040)
Institutions
- Ames Research Center (US)
- Space Telescope Science Institute (US)
- University of Arizona (US)
- University of Leicester (GB)
- Shanghai Jiao Tong University (CN)
- Université Côte d'Azur (FR)
- Johns Hopkins University Applied Physics Laboratory (US)
- University of Oxford (GB)
- McCormick (United States) (US)
- Bay Area Environmental Research Institute (US)
- Université Bourgogne Franche-Comté (FR)
- Observatoire de la Côte d’Azur (FR)
- University of Virginia (US)
- University of Sheffield (GB)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society
- Published
- 2024-09-13
- DOI
- https://doi.org/10.1093/mnras/stae2121
- Citations
- 3
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 0.99
Funders
- National Aeronautics and Space Administration
- California Institute of Technology
- Space Telescope Science Institute
- University of Leicester
- College of Science and Engineering, University of Minnesota
- Science and Technology Facilities Council