The Spectral and Orbital Characterization of Brown Dwarf–White Dwarf Systems

Abstract This research note presents a spectral analysis of the eclipsing brown dwarf–white dwarf (BD–WD) binary SDSS J1411. Using optical and infrared spectra from the Multi-Object Double CCD Spectrographs (MODS) on the Large Binocular Telescope (LBT), I measure the WD’s radial velocities, effective temperature, and surface gravity across its orbit. Fitting the individual H α line yields a radial velocity semiamplitude of 38.66 ± 5.35 km s −1 . A χ 2 minimization over an interpolated grid of WD templates yields T eff = 11,227 ± 1207 K and log 10 g = 7.62 ± 0.69 in CGS units. Cross-correlating against the best-fit template gives a consistent RV of 37.99 ± 4.57 km s −1 . Both RV values agree with previous orbital analyses of SDSS J1411.