Colliding clouds: The star formation trigger of the stellar cluster around BD +40 4124

Leslie W. Looney, Shiya Wang, Murad Hamidouche, Pedro N. Safier, Randolf Klein

Research output: Contribution to journalArticlepeer-review


We present BIMA and SCUBA observations of the young cluster associated with BD +40 4124 in the dense molecular gas tracer CS J = 2 → 1 and the continuum dust emission at λ = 3.1 mm and 850 μm. The dense gas and dust in the system are aligned in a long ridge morphology extending ∼0.4 pc with 16 gas clumps of estimated masses ranging from 0.14 to 1.8 M . A north-south variation in the CS center line velocity can be explained with a two-cloud model. We posit that the BD +40 4124 stellar cluster formed from a cloud-cloud collision. The largest line widths occur near V1318 Cyg S, a massive star affecting its natal environment. In contrast, the dense gas near the other, more evolved, massive stars displays no evidence for disruption; the material must either be processed into the star, dissipate, or relax fairly quickly. The more evolved low-mass protostars are more likely to be found near the massive stars. If the majority of low-mass stars are coeval, the seemingly evolved low-mass protostars are not older: the massive stars have eroded their structures. Finally, at the highest resolution, the λ = 3.1 mm dust emission is resolved into a flattened structure 3100 × 1500 AU with an estimated mass of 3.4 M. The continuum and CS emission are offset by 1.1 from the southern binary source. A simple estimate of the extinction due to the continuum emission structure is AV ∼ 700 mag. From the offset and because the southern source is detected in the optical, the continuum emission is from a previously unknown very young, intermediate-mass, embedded stellar object.

Original languageEnglish (US)
Pages (from-to)330-338
Number of pages9
JournalAstrophysical Journal
Issue number1 I
StatePublished - May 1 2006


  • ISM: clouds
  • ISM: jets and outflows
  • Radio lines: ISM
  • Stars: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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