Formation of wide binaries by turbulent fragmentation

Abstract

Understanding the formation of wide-binary systems of very low-mass stars (M ≤ 0.1 solar masses, M) is challenging1,2,3. The most obvious route is through widely separated low-mass collapsing fragments produced by turbulent fragmentation of a molecular core4,5. However, close binaries or multiples from disk fragmentation can also evolve to wide binaries over a few initial crossing times of the stellar cluster through tidal evolution6. Finding an isolated low-mass wide-binary system in the earliest stage of formation, before tidal evolution could occur, would prove that turbulent fragmentation is a viable mechanism for (very) low-mass wide binaries. Here we report high-resolution ALMA observations of a known wide-separation protostellar binary, showing that each component has a circumstellar disk. The system is too young7 to have evolved from a close binary, and the disk axes are misaligned, providing strong support for the turbulent fragmentation model. Masses of both stars are derived from the Keplerian rotation of the disks; both are very low-mass stars.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: Two compact continuum sources detected in the 1.3-mm continuum (black contours) on top of the C18O J = 2 → 1 integrated intensity (colour image).
Figure 2: Continuum images at two different resolutions.
Figure 3: Protostellar binary disks detected in the high-velocity wings of the C18O J  = 2 → 1 emission line on top of the continuum image (grey scale).
Figure 4: The velocity profiles for high-velocity wings of IRAS 04191+1523 A and B, respectively, along the white lines in Fig. 3.

References

  1. 1

    Béjar, V. J. S. et al. Discovery of a wide companion near the deuterium-burning mass limit in the Upper Scorpius association. Astrophys. J. Lett. 673, L185 (2008).

    ADS  Article  Google Scholar 

  2. 2

    Luhman, K. L., Mamajek, E. E., Allen, P. R., Muench, A. A. & Finkbeiner, D. P. Discovery of a wide binary brown dwarf born in isolation. Astrophys. J. 691, 1265–1275 (2009).

    ADS  Article  Google Scholar 

  3. 3

    Luhman, K. L. The formation and early evolution of low-mass stars and brown dwarfs. Annu. Rev. Astron. Astrophys. 50, 65–106 (2012).

    ADS  Article  Google Scholar 

  4. 4

    Goodwin, S. P., Whitworth, A. P. & Ward-Thompson, D. Simulating star formation in molecular cloud cores. I. The influence of low levels of turbulence on fragmentation and multiplicity. Astron. Astrophys. 414, 633–650 (2004).

    ADS  Article  Google Scholar 

  5. 5

    Fisher, R. T. A turbulent interstellar medium origin of the binary period distribution. Astrophys. J. 600, 769–780 (2004).

    ADS  Article  Google Scholar 

  6. 6

    Marks, M. & Kroupa, P. Inverse dynamical population synthesis. Constraining the initial conditions of young stellar clusters by studying their binary populations. Astron. Astrophys. 543, A8 (2012).

    ADS  Article  Google Scholar 

  7. 7

    Dunham, M. M. et al. The Spitzer c2d survey of nearby dense cores. I. First direct detection of the embedded source in IRAM 04191+1522. Astrophys. J. 651, 945–959 (2006).

    ADS  Article  Google Scholar 

  8. 8

    Offner, S. S. R., Kratter, K. M., Matzner, C. D., Krumholz, M. R. & Klein, R. I. The formation of low-mass binary star systems via turbulent fragmentation. Astrophys. J. 725, 1485–1494 (2010).

    ADS  Article  Google Scholar 

  9. 9

    Kratter, K. M., Matzner, C. D., Krumholz, M. R. & Klein, R. I. On the role of disks in the formation of stellar systems: a numerical parameter study of rapid accretion. Astrophys. J. 708, 1585–1597 (2010).

    ADS  Article  Google Scholar 

  10. 10

    Bate, M. R. Stellar, brown dwarf and multiple star properties from a radiation hydrodynamical simulation of star cluster formation. Mon. Not. R. Astron. Soc. 419, 3115–3146 (2012).

    ADS  Article  Google Scholar 

  11. 11

    Dunham, M. M . et al. in Protostars and Planets VI (ed. Beuther, H ., Klessen, R. S ., Dullemond, C. P . & Henning, T. ) 195–218 (Univ. Arizona Press, 2014).

    Google Scholar 

  12. 12

    Tobin, J. J. et al. The VLA Nascent Disk and Multiplicity survey of Perseus protostars (VANDAM). II. Multiplicity of protostars in the Perseus molecular cloud. Astrophys. J. 818, 73 (2016).

    ADS  Article  Google Scholar 

  13. 13

    Tobin, J. J. et al. A triple protostar system formed via fragmentation of a gravitationally unstable disk. Nature 538, 483–486 (2016).

    ADS  Article  Google Scholar 

  14. 14

    Pineda, J. E. et al. The formation of a quadruple star system with wide separation. Nature 518, 213–215 (2015).

    ADS  Article  Google Scholar 

  15. 15

    Offner, S. S. R., Dunham, M. M., Lee, K. I., Arce, H. G. & Fielding, D. B. The turbulent origin of outflow and spin misalignment in multiple star systems. Astrophys. J. Lett. 827, L11 (2016).

    ADS  Article  Google Scholar 

  16. 16

    Bonnell, I. A. & Bate, M. R. Massive circumbinary discs and the formation of multiple systems. Mon. Not. R. Astron. Soc. 269, L45–L48 (1994).

    ADS  Article  Google Scholar 

  17. 17

    Lee, J. W. Y., Hull, C. L. H. & Offner, S. S. R. Synthetic observations of magnetic fields in protostellar cores. Astrophys. J. 834, 201 (2017).

    ADS  Article  Google Scholar 

  18. 18

    Jensen, E. L. N., Mathieu, R. D., Donar, A. X. & Dullighan, A. Testing protoplanetary disk alignment in young binaries. Astrophys. J. 600, 789–803 (2004).

    ADS  Article  Google Scholar 

  19. 19

    Jensen, E. L. N. & Akeson, R. Misaligned protoplanetary disks in a young binary star system. Nature 511, 567–569 (2014).

    ADS  Article  Google Scholar 

  20. 20

    Salyk, C. et al. ALMA Observations of the T Tauri binary system AS 205: evidence for molecular winds and/or binary interactions. Astrophys. J. 792, 68 (2014).

    ADS  Article  Google Scholar 

  21. 21

    Williams, J. P. et al. ALMA observations of a misaligned binary protoplanetary disk system in Orion. Astrophys. J. 796, 120 (2014).

    ADS  Article  Google Scholar 

  22. 22

    Duchêne, G., Bouvier, J., Bontemps, S., André, P. & Motte, F. Multiple protostellar systems. I. A deep near infrared survey of Taurus and Ophiuchus protostellar objects. Astron. Astrophys. 427, 651–665 (2004).

    ADS  Article  Google Scholar 

  23. 23

    Luhman, K. L., Allen, P. R., Espaillat, C., Hartmann, L. & Calvet, N. the disk population of the Taurus star-forming region. Astrophys. J. Suppl. 186, 111–174 (2010).

    ADS  Article  Google Scholar 

  24. 24

    Connelley, M. S., Reipurth, B. & Tokunaga, A. T. The evolution of the multiplicity of embedded protostars. I. Sample properties and binary detections. Astron. J. 135, 2496–2525 (2008).

    ADS  Article  Google Scholar 

  25. 25

    Dang-Duc, C., Phan-Bao, N. & Dao-Van, D. T. Two confirmed class I very low-mass objects in Taurus. Astron. Astrophys. 588, L2 (2016).

    ADS  Article  Google Scholar 

  26. 26

    Bulger, J. et al. The Taurus Boundary of Stellar/Substellar (TBOSS) Survey. I. Far-IR disk emission measured with Herschel. Astron. Astrophys. 570, A29 (2014).

    Article  Google Scholar 

  27. 27

    Tobin, J. J. et al. A 0.2-solar-mass protostar with a Keplerian disk in the very young L1527 IRS system. Nature 492, 83–85 (2012).

    ADS  Article  Google Scholar 

  28. 28

    Young, C. H. et al. Submillimeter Common-User Bolometer Array mapping of Spitzer c2d small clouds and cores. Astron. J. 132, 1998–2013 (2006).

    ADS  Article  Google Scholar 

  29. 29

    André, P., Motte, F. & Bacmann, A. Discovery of an extremely young accreting protostar in Taurus. Astrophys. J. Lett. 513, L57–L60 (1999).

    ADS  Article  Google Scholar 

  30. 30

    Rebull, L. M. et al. The Taurus Spitzer Survey: new candidate Taurus members selected using sensitive mid-infrared photometry. Astrophys. J. Suppl. 186, 259–307 (2010).

    ADS  Article  Google Scholar 

  31. 31

    Kroupa, P. Inverse dynamical population synthesis and star formation. Mon. Not. R. Astron. Soc. 277, 1491–1506 (1995).

    ADS  Article  Google Scholar 

  32. 32

    McMullin, J. P., Waters, B., Schiebel, D., Young, W. & Golap, K. in Astronomical Data Analysis Software and Systems XVI (eds Shaw, R. A., Hill, F. & Bell, D. J.) Astronomical Society of the Pacific Conference Series Vol. 376, 127 (2007).

  33. 33

    Andrews, S. M. & Williams, J. P. Circumstellar dust disks in Taurus–Auriga: the submillimeter perspective. Astrophys. J. 631, 1134–1160 (2005).

    ADS  Article  Google Scholar 

Download references

Acknowledgements

This paper makes use of the following ALMA data: ADS/JAO.ALMA#2013.1.00537.S and 2015.1.00186.S. ALMA is a partnership of the European Southern Observatory (representing its member states), the National Science Foundation (United States) and National Institutes of Natural Sciences (Japan), together with the National Research Council (Canada), the National Science Council and Academia Sinica Institute of Astronomy and Astrophysics (Taiwan), and Korea Astronomy and Space Science Institute (KASI, Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. J.-E.L. was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (grant no. NRF-2015R1A2A2A01004769) and KASI under the R&D program (project no. 2015-1-320-18) supervised by the Ministry of Science, ICT and Future Planning. N.J.E. thanks KASI for support for a visit to participate in this work.

Author information

Affiliations

Authors

Contributions

J.-E.L. and S.L. performed the detailed calculations used in the analysis. S.L. and K.T. reduced the ALMA data. J.-E.L. wrote the manuscript. All authors were participants in the discussion of results, determination of the conclusions and revision of the manuscript.

Corresponding author

Correspondence to Jeong-Eun Lee.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Figures 1–3 and Supplementary Tables 1–3. (PDF 183 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Lee, JE., Lee, S., Dunham, M. et al. Formation of wide binaries by turbulent fragmentation. Nat Astron 1, 0172 (2017). https://doi.org/10.1038/s41550-017-0172

Download citation

Further reading

Search

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing