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A resolved outflow of matter from a brown dwarf


The birth of stars involves not only accretion but also, counter-intuitively, the expulsion of matter in the form of highly supersonic outflows1,2. Although this phenomenon has been seen in young stars, a fundamental question is whether it also occurs among newborn brown dwarfs: these are the so-called ‘failed stars’, with masses between stars and planets, that never manage to reach temperatures high enough for normal hydrogen fusion to occur3. Recently, evidence for accretion in young brown dwarfs has mounted4,5,6, and their spectra show lines that are suggestive of outflows7,8,9. Here we report spectro-astrometric data that spatially resolve an outflow from a brown dwarf. The outflow's characteristics appear similar to, but on a smaller scale than, outflows from normal young stars. This result suggests that the outflow mechanism is universal, and perhaps relevant even to the formation of planets.

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Figure 1: Resolving the outflow from ρ Oph 102.
Figure 2: The outflow signature in the Hα profile of ρ Oph 102.


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This work was supported in part by Science Foundation Ireland and the JETSET Marie Curie research training network.

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Correspondence to Emma T. Whelan.

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Reprints and permissions information is available at The authors declare no competing financial interests.

Supplementary information

Supplementary Discussion

Contains details of the spectro-astrometric technique, the method by which any displacement in the emission lines of p-Oph 102 is measured, and details of Additional ELRs and the critical density for a forbidden line scales with Mjet1/2 (DOC 995 kb)

Supplementary Figure S1

Continuum fitting and removal, using a long-slit spectrum of a typical young star, with an outflow (in this case DG Tau). (PDF 59 kb)

Supplementary Figure S2

Spectro-astrometric plots in the vicinity of the [OI] γ6300 line of p-Oph 102, before (top) and after (bottom) continuum straightening. (PDF 37 kb)

Supplementary Figure S3

The [OI]γγ 6300, 6363 ELRs were initially fitted with the night sky (NS) lines still present (left panel). (PDF 59 kb)

Supplementary Figure S4

The spectro-astrometric plots for the Liγ6708 and HeIγ6678 lines (PDF 44 kb)

Supplementary Figure S5

Displacement in the [OI] γγ6300, 6363, [SII]γ 6731 and HeI γ6678 ELRs, with respect to the continuum measured across a large part of the individual orders. (PDF 63 kb)

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Whelan, E., Ray, T., Bacciotti, F. et al. A resolved outflow of matter from a brown dwarf. Nature 435, 652–654 (2005).

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