Multicolour polarization and CO observations towards a dark filament in Musca

• Published in: Monthly notices of the Royal Astronomical Society 1993-11, Vol.265 (1), p.1-11
• Main Authors: Arnal, E. M., Morras, R., Rizzo, J. R.
• Format: Article
• Language: English
• Subjects: Astronomy; dust; Earth, ocean, space; Exact sciences and technology; extinction; Interstellar medium (ism) and nebulae in milky way; ISM: clouds; ISM: individual: Musca; ISM: magnetic fields; ISM: molecules; Molecular clouds, h2 clouds, dense clouds, and dark clouds; polarization; Stellar systems. Galactic and extragalactic objects and systems. The universe
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/265.1.1

Multicolour polarimetry with high sensitivity of stars in the region of the Musca filamentary cloud and $^{12}\text CO (J = 1\rightarrow 0)$ observations towards the same area are reported. A lower distance limit of 150 pc is derived for this cloud from a polarization percentage versus distance modulus diagram. From the carbon monoxide data, a total mass of 170 solar masses is obtained. The molecular gas density is of the order of 300 cm–3. The direction of the observed projected interstellar magnetic field is almost perpendicular to the major axis of the cloud. We believe that the magnetic field has played a significant role in the evolution of this cloud. Based on the spatial variation of the ratio of total to selective extinction (Rυ is 3.72 for stars seen close to the dark filament and 3.37 elsewhere in the region), the grains associated with the dark cloud seem to be large in comparison with those usually present in the interstellar medium. Based on its distance and radial velocity, it is suggested that this cloud belongs to Gould's Belt.