Structural and compositional properties of brown dwarf disks: the case of 2MASS J04442713+2512164

Bouy, H.; Huélamo, N.; Pinte, C.; Olofsson, J.; Barrado Y Navascués, D.; Martín, E. L.; Pantin, E.; Monin, J.-L.; Basri, G.; Augereau, J.-C.; Ménard, F.; Duvert, G.; Duchêne, G.; Marchis, F.; Bayo, A.; Bottinelli, S.; Lefort, B.; Guieu, S.
Referencia bibliográfica

Astronomy and Astrophysics, Volume 486, Issue 3, 2008, pp.877-890

Fecha de publicación:
8
2008
Número de autores
18
Número de autores del IAC
2
Número de citas
51
Número de citas referidas
43
Descripción
Aims: To improve our understanding of substellar formation, we have performed a compositional and structural study of a brown dwarf disk. Methods: We present the results of photometric, spectroscopic, and imaging observations of 2MASS J04442713+2512164, a young brown dwarf (M 7.25) member of the Taurus association. Our dataset, combined with results from the literature, provides a complete coverage of the spectral energy distribution from the optical range to the millimeter, including the first photometric measurement of a brown dwarf disk at 3.7 mm, and allows us to perform a detailed analysis of the disk properties. Results: The target was known to have a disk. High-resolution optical spectroscopy shows that it is accreting intensely, and powers both a jet and an outflow. The disk structure is similar to what is observed for more massive TTauri stars. Spectral decomposition models of Spitzer/IRS spectra suggest that the mid-infrared emission from the optically thin disk layers is dominated by grains with intermediate sizes (1.5 μm). Crystalline silicates are significantly more abundant in the outer part and/or deeper layers of the disk, implying very efficient mixing and/or additional annealing processes. Submillimeter and millimeter data indicate that most of the disk mass is in large grains (>1 mm).