Title

Optical Linear Polarization In Ultra Cool Dwarfs: A Tool To Probe Dust In The Ultra Cool Dwarf Atmospheres

Keywords

Atmospheric effects; Polarization; Stars: low-mass, brown dwarfs

Abstract

Aims: Recent studies have detected linear polarization in L dwarfs in the optical I band. Theoretical models have been developed to explain this polarization. These models predict higher polarization at shorter wavelengths. We discuss the polarization in the R and I band of 4 ultra cool dwarfs. Methods: We report linear polarization measurements of 4 ultra cool dwarfs in the R and I bands using the Intermediate dispersion Spectrograph and Imaging System (ISIS) mounted on the 4.2 m William Herschel Telescope (WHT). Results: As predicted by theoretical models, we find a higher degree of polarization in the R band when compared to polarization in the I band for 3/4 of these ultra cool dwarfs. This suggests that dust scattering asymmetry is caused by oblateness. We also show how these measurements fit the theoretical models. A case for variability of linear polarization is found, which suggests the presence of randomly distributed dust clouds. We also discuss one case for the presence of a cold debris disk. © 2009 ESO.

Publication Date

12-4-2009

Publication Title

Astronomy and Astrophysics

Volume

508

Issue

3

Number of Pages

1423-1427

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1051/0004-6361/200911830

Socpus ID

72849125099 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/72849125099

This document is currently not available here.

Share

COinS