Evolution of spheroidal dust in electrically active sub-stellar atmospheres
arXiv:2010.09431 · doi:10.1051/0004-6361/202037589
Abstract
Understanding the source of sub-stellar polarimetric observations in the optical and near-infrared is key to characterizing sub-stellar objects and developing potential diagnostics for determining properties of their atmospheres. Differential scattering from a population of aligned, non-spherical dust grains is a potential source of polarization that could be used to determine geometric properties of the dust clouds. This paper addresses the problem of the spheroidal growth of dust grains in electrically activated sub-stellar atmospheres. It presents the novel application of a mechanism whereby non-spherical, elongated dust grains can be grown via plasma deposition as a consequence of the surface electric field effects of charged dust grains. We numerically solve the differential equations governing the spheroidal growth of charged dust grains via plasma deposition as a result of surface electric field effects in order to determine how the dust eccentricity and the dust particle eccentricity distribution function evolve with time. From these results, we determine the effect of spheroidal dust on the observed linear polarization. Numerical solutions show that defines a watershed eccentricity, where the eccentricity of grains with an initial eccentricity less than (greater than) this value decreases (increases) and spherical (spheroidal) growth occurs. This produces a characteristic bimodal eccentricity distribution function yielding a fractional change in the observed linear polarization of up to corresponding to dust grains of maximal eccentricity at wavelengths of m, consistent with the near infrared observational window. The results presented here are relevant to the growth of non-spherical, irregularly shaped dust grains of general geometry where non-uniform surface electric field effects of charged dust grains are significant.
arXiv comment10 pages, 6 figures, accepted to Astronomy and Astrophysics
References in corpus (56)
- Precipitating Condensation Clouds in Substellar Atmospheres
- Magnetic fields of non-degenerate stars
- Neglected Clouds in T and Y Dwarf Atmospheres
- A comparison of chemistry and dust cloud formation in ultracool dwarf model atmospheres
- A catalogue of rotation and activity in early-M stars
- Activity and Kinematics of Ultracool Dwarfs Including An Amazing Flare Observation
- Dynamic mineral clouds on HD 189733b I. 3D RHD with kinetic, non-equilibrium cloud formation
- Dust in the Photospheric Environment: Unified Cloudy Models of M, L, and T Dwarfs
- Simultaneous Multi-Wavelength Observations of Magnetic Activity in Ultracool Dwarfs. III. X-ray, Radio, and H-alpha Activity Trends in M and L Dwarfs
- Atmospheric dynamics of terrestrial exoplanets over a wide range of orbital and atmospheric parameters
- Dust in brown dwarfs and extra-solar planets II. Cloud formation for cosmologically evolving abundances
- Auroral radio emission from late L and T dwarfs: A new constraint on dynamo theory in the substellar regime
- Formation of Silicate and Titanium Clouds on Hot Jupiters
- Simulating the cloudy atmospheres of HD 209458 b and HD 189733 b with the 3D Met Office Unified Model
- Atmospheres of Brown Dwarfs
- Origin of electron cyclotron maser-induced radio emissions at ultra-cool dwarfs: magnetosphere-ionosphere coupling currents
- A Survey for H-alpha Emission from Late L dwarfs and T dwarfs
- Characterizing exoplanetary atmospheres through infrared polarimetry
- Ionisation in atmospheres of Brown Dwarfs and extrasolar planets I The role of electron avalanche
- Optical Linear Polarization of Late M- and L-Type Dwarfs
- Optical Linear Polarimetry of Ultra Cool Dwarfs
- Ionisation in atmospheres of Brown Dwarfs and extrasolar planets III. Breakdown conditions for mineral clouds
- A Chandra X-ray detection of the L dwarf binary Kelu-1: Simultaneous Chandra and Very Large Array observations
- Observed Polarization of Brown Dwarfs Suggests Low Surface Gravity
- Polarized scattered light from self-luminous exoplanets. Three-dimensional scattering radiative transfer with ARTES
- Probing Dust in the Atmosphere of Brown Dwarfs Through Polarization
- Ionisation in atmospheres of Brown Dwarfs and extrasolar planets II Dust-induced collisional ionization
- Ionization in atmospheres of Brown Dwarfs and extrasolar planets IV. The Effect of Cosmic Rays
- Radio Flaring from the T6 Dwarf WISEPC J112254.73+255021.5 with A Possible Ultra-short Periodicity
- A Signature of Chromospheric Activity in Brown Dwarfs Revealed by 2.5-5.0 Micron AKARI Spectra
- Reference study to characterise plasma and magnetic properties of ultra-cool atmospheres
- Magnetic Properties of Dust Grains, Effect of Precession and Radiative Torque Alignment
- Variable and polarized radio emission from the T6 brown dwarf WISEP J112254.73+255021.5
- Quasi-Quiescent Radio Emission from the First Radio-Emitting T Dwarf
- The First Millimeter Detection of a Non-Accreting Ultracool Dwarf
- Lightning climatology of exoplanets and brown dwarfs guided by Solar System data
- Ionisation in atmospheres of brown dwarfs and extrasolar planets VI: Properties of large-scale discharge events
- Near-infrared Linear Polarization of Ultracool Dwarfs
- Explaining the Observed Polarization from Brown Dwarfs by Single Dust Scattering
- Detection of Radio Emission from the Hyperactive L Dwarf 2MASS J13153094-2649513AB
- Polarisation of very-low-mass stars and brown dwarfs
- Rotation, magnetism, and metallicity of M dwarf systems
- Ionization in Atmospheres of Brown Dwarfs and Extrasolar Planets V: Alfvén Ionization
- 2MASS 1315-2649: A High Proper Motion L Dwarf with Strong H-alpha Emission
- Optical linear polarization in ultra cool dwarfs: A tool to probe dust in the ultra cool dwarf atmospheres
- Optical and near-infrared linear polarization of low and intermediate-gravity ultra-cool dwarfs
- Self-consistent atmosphere modeling with cloud formation for low-mass stars and exoplanets
- Electrostatic activation of prebiotic chemistry in substellar atmospheres
- Ionisation and discharge in cloud-forming atmospheres of brown dwarfs and extrasolar planets
- Jupiter as a Giant Cosmic Ray Detector
- Polarization of Trappist-1 by the Transit of its Planets
- Photo-polarimetric characteristics of brown dwarfs, Part I: uniform cloud decks
- Time-resolved image polarimetry of Trappist-1 during planetary transits
- Testing the existence of optical linear polarization in young brown dwarfs
- Dust cloud evolution in sub-stellar atmospheres via plasma deposition and plasma sputtering
- The effect of internal gravity waves on cloud evolution in sub-stellar atmospheres