ε Indi Ba,Bb: The nearest binary brown dwarf

By M. McCaughrean, L. Close, R. Scholz, R. Lenzen, B. Biller, W. Brandner, M. Hartung, N. A. I. Potsdam, Heidelberg · Germany, S. Observatory and 7 more. 2003

144 citations recorded by the source corpus.

We have carried out high angular resolution near-infrared imaging and low-resolution ($R\sim1000$) spectroscopy of the nearest known brown dwarf, e Indi B, using the ESO VLT NAOS/CONICA adaptive optics system. We find it to be a close binary (as also noted by Volk et al. 2003), with an angular separation of 0.732 arcsec, corresponding to 2.65 AU at the 3.626 pc distance of the e Indi system. In our discovery paper (Scholz et al. 2003), we concluded that e Indi B was a ~50 M Jup T2.5 dwarf: our revised finding is that the two system components ( e Indi Ba and e Indi Bb) have spectral types of T1 and T6, respectively, and estimated masses of 47 and 28 M Jup , respectively, assuming an age of 1.3 Gyr. Errors in the masses are ± 10 and ± 7 M Jup , respectively, dominated by the uncertainty in the age determination (0.8–2 Gyr range). This uniquely well-characterised T dwarf binary system should prove important in the study of low-mass, cool brown dwarfs. The two components are bright and relatively well-resolved: e Indi B is the only T dwarf binary in which spectra have been obtained for both components. The system has a well-established distance and age. Finally, their orbital motion can be measured on a fairly short timescale (nominal orbital period ~15 yrs), permitting an accurate determination of the true total system mass, helping to calibrate brown dwarf evolutionary models.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/6d15bb3d9f929f8afd0b2b8b0fce780880519979

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Citations in the corpus

Individual Dynamical Masses of Ultracool Dwarfs (2017, unknown): “5; McCaughrean et al. 2004), and 2MASS J22551861−5713056AB (L6; Reid et al. 2008a).”
Discovery of Two T Dwarf Companions with the Spitzer Space Telescope (2006, background): “…Oppenheimer et al. 1995), Gl 570 D (Burgasser et al. 2000), Gl 337 D (Wilson et al. 2001; Burgasser et al. 2005), ǫ Ind B and C (Scholz et al. 2003; McCaughrean et al. 2004), and SCR 1845 B (Biller et al. 2006), all of which orbit nearby stars that are older than ∼ 1 Gyr and have no known planets.”
Seventy-One New L and T Dwarfs from the Sloan Digital Sky Survey (2006, methodology): “…imaging searches for close-binary brown dwarfs are being conducted with the Hubble Space Telescope and ground-based adaptive optics imagers (Burgasser et al. 2003; Bouy et al. 2003; McCaughrean et al. 2004; Golimowski et al. 2004b; Liu & Leggett 2005; Liu et al. 2006; Burgasser et al. 2006b).”