Probing the magnetosphere of the M8.5 dwarf TVLM 513-46546 by modelling its auroral radio emission. Hint of star exoplanet interaction?

Journal
Date Issued
2017
Author(s)
•
•
•
•
•
Cerrigone, L.
DOI
Abstract
In this paper, we simulate the cyclic circularly polarized pulses of the ultracool dwarf TVLM 513-46546, observed with the Very Large Array at 4.88 and 8.44 GHz on 2006 May, by using a three-dimensional model of the auroral radio emission from the stellar magnetosphere. During this epoch, the radio light curves are characterized by two pulses left-hand polarized at 4.88 GHz, and one doubly peaked (of opposite polarizations) pulse at 8.44 GHz. To take into account the possible deviation from the dipolar symmetry of the stellar magnetic-field topology, the model described in this paper is also able to simulate the auroral radio emission from a magnetosphere shaped like an offset dipole. To reproduce the timing and pattern of the observed pulses, we explored the space of parameters controlling the auroral beaming pattern and the geometry of the magnetosphere. Through the analysis of the TVLM 513-46546 auroral radio emission, we derive some indications on the magnetospheric field topology that is able to simultaneously reproduce the timing and patterns of the auroral pulses measured at 4.88 and 8.44 GHz. Each set of model solutions simulates two auroral pulses (singly or doubly peaked) per period. To explain the presence of only one 8.44 GHz pulse per period, we analyse the case of auroral radio emission limited only to a magnetospheric sector activated by an external body, like the case of the interaction of Jupiter with its moons.
Volume
469
Issue
2
Start page
1949
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2017MNRAS.469.1949L
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

stx995.pdf

Description
PDF editoriale
Size

6.41 MB

Format

Adobe PDF

Checksum (MD5)

272c629837eb1c822c6aea176b16cc9c

Loading...
Thumbnail Image
Name

1611.00511.pdf

Description
arXiv
Size

6.59 MB

Format

Adobe PDF

Checksum (MD5)

92e0d490929e86f3760ea85dbaed074c