2017/05/17 by R. Siebenmorgen, Н. В. Вощинников, N. V. Voshchinnikov +3 · 11 citations
Chemistry · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Chemistry #Cosmic dust #Extinction (optical mineralogy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Interstellar medium #Molecular physics #Optics #Physics #Polarization (electrochemistry) #RADIUS #Silicate #Spectral line #Stars #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1016/j.pss.2017.05.007
published in Planetary and Space Science 149, 64-71 (Elsevier BV) · Planetary and Space Science, Planetary and Space Science, DOI:10.1016/j.pss.2017.05.007
openalex publication_date 2017/05/17 · arxiv created 2017/05/22 · openalex created_date 2017/05/26 · arxiv updated 2017/12/20 · openalex updated_date 2026/08/05
We present polarisation spectra of seven stars in the lines-of-sight towards the Sco OB1 association. Our spectra were obtained within the framework of the Large Interstellar Polarization Survey carried out with the FORS instrument of the ESO VLT. We have modelled the wavelength-dependence of extinction and linear polarisation with a dust model for the diffuse interstellar medium which consists of a mixture of particles with size ranging from the molecular domain of 0.5 nm up to 350 nm. We have included stochastically heated small dust grains with radii between 0.5 and 6 nm made of graphite and silicate, as well as polycyclic aromatic hydrocarbon molecules (PAHs), and we have assumed that larger particles are prolate spheroids made of amorphous carbon and silicate. Overall, a dust model with eight free parameters best reproduces the observations. Reducing the number of free parameters leads to results that are inconsistent with cosmic abundance constraints. We found that aligned silicates are the dominant contributor to the observed polarisation, and that the polarisation spectra are best-fit by a lower limit of the equivolume sphere radius of aligned grains of 70 - 200nm.