Polarization of L Dwarfs by Dust Scattering
arXiv:astro-ph/0502309 · doi:10.1086/429659
Abstract
The degree of polarization in L dwarfs of spectral types L0 to L6 resulting from dust scattering in a rotation-induced oblate photosphere is calculated. Assuming that forsterite is the main condensate, the atmospheric dust distribution is derived for different spectral types based on a chemical equilibrium model. The degree of polarization at optical is then calculated using a single scattering model. The expected linear polarization at optical is found to peak at around spectral type L1. For a fixed rotational velocity, the degree of polarization decreases from hotter to cooler objects. However, with the increase in mean grain size, the degree of linear polarization reduces significantly. We fit the recently observed linear polarimetric data of L dwarfs and find that single dust scattering model coupled with the chemical equilibrium models of condensates is consistent with the observational results.
Latex (aastex sty), 23 pages including 7 postscript figures. Accepted for publication in the Astrophysical Journal (Part 1)
References in corpus (8)
- Near-Infrared Photometry and Spectroscopy of L and T Dwarfs: the Effects of Temperature, Clouds, and Gravity
- L' and M' Photometry of Ultracool Dwarfs
- Preliminary Parallaxes of 40 L and T Dwarfs from the U.S. Naval Observatory Infrared Astrometry Program
- Measuring the Oblateness and Rotation of Transiting Extrasolar Giant Planets
- Dust in the Photospheric Environment III. A Fundamental Element in the Characterization of Ultracool Dwarfs
- Optical Linear Polarization of Late M- and L-Type Dwarfs
- Dust in the Photospheric Environment II. Effect on the Near Infrared Spectra of L and T Dwarfs
- Explaining the Observed Polarization from Brown Dwarfs by Single Dust Scattering
Cited by in corpus (14)
- Observed Polarization of Brown Dwarfs Suggests Low Surface Gravity
- Polarized scattered light from self-luminous exoplanets. Three-dimensional scattering radiative transfer with ARTES
- Cloudy Atmosphere of the Extra-solar Planet HD189733b : A Possible Explanation of the Detected B-band Polarization
- Polarization of Starlight by Unresolved and Oblate Extra-solar Planet in Elliptical Orbit
- Near-infrared Linear Polarization of Ultracool Dwarfs
- Linear polarization of rapidly rotating ultracool dwarfs
- Multiple Scattering Polarization of Substellar-mass Objects : T-dwarfs
- Polarisation of very-low-mass stars and brown dwarfs
- Optical linear polarization in ultra cool dwarfs: A tool to probe dust in the ultra cool dwarf atmospheres
- Polarization of Trappist-1 by the Transit of its Planets
- Polarimetric Detection of Exoplanets Transiting T- and L- Brown Dwarfs
- Testing the existence of optical linear polarization in young brown dwarfs
- Short-term spectroscopic monitoring of two cool dwarfs with strong magnetic fields
- Polarization of Rotationally Oblate Self-Luminous Exoplanets with Anisotropic Atmospheres