Using the Starlight Polarization Efficiency Integral to Constrain Shapes and Porosities of Interstellar Grains

نویسندگان

چکیده

We have developed a new method for using the observed starlight polarization and polarized submillimeter emission to constrain shapes porosities of interstellar grains. first present modified picket-fence approximation verify that it is sufficiently accurate modeling polarization. then introduce integral Πobs as measure overall strength starlight, efficiency Φ characterize effectiveness different grain types producing starlight. The ratio Πobs/Φ determines mass-weighted alignment 〈falign〉 Approximating aligned grains in ISM spheroids, we use show constrains minimum degree asphericity. For porosity , axial ∼1.4 oblate or ∼1.8 prolate spheroids. If are porous, more extreme ratios required. same produce able provide at wavelengths but with further limits on shape porosity. Porosities ruled out. can be approximated by "astrodust" predict 10 μm pV: p(10 μm)/pV = 0.219 ± 0.029. Cyg OB2-12, μm) (2.1 0.3)%, which should observable.

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ژورنال

عنوان ژورنال: The Astrophysical Journal

سال: 2021

ISSN: ['2041-8213', '2041-8205']

DOI: https://doi.org/10.3847/1538-4357/ac0050