NLTT5306B: An inflated, weakly irradiated brown dwarf

S. L. Casewell, J. Debes, I. P. Braker, M. C. Cushing, G. Mace, M. S. Marley, J. Davy Kirkpatrick

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


We present Spitzer observations at 3.6 and 4.5 μm and a near-infrared IRTF SpeX spectrum of the irradiated brown dwarf NLTT5306B. We determine that the brown dwarf has a spectral type of L5 and is likely inflated, despite the low effective temperature of the white dwarf primary star. We calculate brightness temperatures in the Spitzer wavebands for both the model radius, and Roche Lobe radius of the brown dwarf, and conclude that there is very little day-night side temperature difference. We discuss various mechanisms by which NLTT5306B may be inflated, and determine that while low-mass brown dwarfs (M < 35 MJup) are easily inflated by irradiation from their host star, very few higher mass brown dwarfs are inflated. The higher mass brown dwarfs that are inflated may be inflated by magnetic interactions or may have thicker clouds.

Original languageEnglish (US)
Pages (from-to)5318-5324
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Dec 1 2020
Externally publishedYes


  • binaries: close
  • brown dwarfs
  • white dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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