Retrieving Dust Grain Sizes from Photopolarimetry: An Experimental Approach
| Autor: | Olga Muñoz, D. Guirado, F. Moreno, T. Jardiel, E. Frattin, Amador C. Caballero, Julien Milli, Juan L. Ramos, M. Peiteado, J. C. Gómez-Martín, François Ménard |
|---|---|
| Přispěvatelé: | European Commission, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Junta de Andalucía, European Science Foundation |
| Rok vydání: | 2021 |
| Předmět: |
Earth and Planetary Astrophysics (astro-ph.EP)
Physics Range (particle radiation) Scattering Linear polarization Experimental techniques FOS: Physical sciences Astronomy and Astrophysics Polarization (waves) Resonance (particle physics) Computational physics Spherical model Debris disks Space and Planetary Science Coma dust Particle size Astrophysics - Instrumentation and Methods for Astrophysics Spectropolarimetry Instrumentation and Methods for Astrophysics (astro-ph.IM) Astrophysics - Earth and Planetary Astrophysics Cosmic dust |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 1538-4365 0067-0049 |
| Popis: | Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. We present the experimental phase function, degree of linear polarization (DLP), and linear depolarization (δ L ) curves of a set of forsterite samples representative of low-absorbing cosmic dust particles. The samples are prepared using state-of-the-art size-segregating techniques to obtain narrow size distributions spanning a broad range of the scattering size parameter domain. We conclude that the behavior of the phase function at the side- and back-scattering regions provides information on the size regime, the position and magnitude of the maximum of the DLP curve are strongly dependent on particle size, the negative polarization branch is mainly produced by particles with size parameters in the ∼6 to ∼20 range, and the δ L is strongly dependent on particle size at all measured phase angles except for the exact backward direction. From a direct comparison of the experimental data with computations for spherical particles, it becomes clear that the use of the spherical model for simulating the phase function and DLP curves of irregular dust produces dramatic errors in the retrieved composition and size of the scattering particles: The experimental phase functions are reproduced by assuming unrealistically high values of the imaginary part of the refractive index. The spherical model does not reproduce the bell-shaped DLP curve of dust particles with sizes in the resonance and/or geometric optics size domain. Thus, the use of the Mie model for analyzing polarimetric observations might prevent locating dust particles with sizes of the order of or larger than the wavelength of the incident light. © 2021. The Author(s). Published by the American Astronomical Society. This work has been funded by the Spanish State Research Agency and Junta de Andalucía through grants LEONIDAS (RTI2018-095330-B-100) and P18-RT-1854, and the Center of Excellence Severo Ochoa award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). T.J. acknowledges the European Science Foundation (ESF) and the Ramon y Cajal Program of MICINN for their financial support. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|