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Gas flow and accretion via spiral streamers and circumstellar disks in a young binary protostar

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Science  04 Oct 2019:
Vol. 366, Issue 6461, pp. 90-93
DOI: 10.1126/science.aaw3491
  • Fig. 1 Dust distribution in [BHB2007] 11 on scales from the core to the circumstellar disks.

    (A) The core of Barnard 59 observed at 250 μm with the Herschel space telescope (20). (B) The [BHB2007] 11 disk and envelope observed at 1.3 mm with ALMA (8). The contours indicate intensity levels of 30, 60, 70, and 450 times the map noise of 62 μJy per beam (1 Jy = 10−26 W m−2 Hz−1). Intensity levels are scaled logarithmically in (A) and (B). (C) Zoomed-in view of the circumbinary disk, revealing the dust filaments surrounding the protobinary system, where [BHB2007] 11A is the northern component and [BHB2007] 11B is the southern and brighter component. The dashed lines are the intensity contours from (B). In (B) and (C), the ALMA synthesized beam is shown in the bottom left corner.

  • Fig. 2 Small-scale kinematics in [BHB2007] 11 measured from CO molecular line emission.

    (A) High-velocity components of the CO emission (with respect to the ambient local standard of rest velocity of [BHB2007] 11, vlsr ~ 3.6 km s−1) overlaid on the continuum map (gray scale). Circles indicate the position of CO emission peaks in each velocity channel (see the color bar). CO data between −2 and 9 km s−1 (indicated as a shaded area in the color bar) are not shown because most gas close to the ambient velocity is filtered out by the interferometer and/or arises from extended emission from outflows or the envelope. Circle sizes denote the uncertainty on the absolute position (9). (B) CO mean spectrum extracted from the disk area showing the CO velocity channels used in (A). The shaded areas indicate the CO velocity components that exceed the reference H2CO spectrum associated with the rotation of the circumbinary disk (9). The faint dashed lines show the strong filtering of the CO line near the systemic velocity of the source.

  • Fig. 3 Centimetric emission associated with the binary system.

    Continuum emission at 0.94 cm (32.5 GHz) associated with the [BHB2007] 11 binary system, observed with the VLA. Contours are at 3, 5, 10, 15, 20, and 25 times the map noise of 12 μJy per beam; the background image is the ALMA map from Fig. 1C. The extended emission to the east of [BHB2007] 11A suggests a radio jet associated with this source. The VLA synthesized beam is shown in the bottom left corner.

Supplementary Materials

  • Gas flow and accretion via spiral streamers and circumstellar disks in a young binary protostar

    F. O. Alves, P. Caselli, J. M. Girart, D. Segura-Cox, G. A. P. Franco, A. Schmiedeke, B. Zhao

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods 
    • Figs. S1 to S3
    • Table S1
    • References 

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