Accreting Brown Dwarf and Disc, Spectra and Photometry
Nathan Mayne , Tim Harries
These pages outline research on the interaction of low mass stars
(brown dwarfs) and the disc of material, orbiting the star, left over
from the star formation process. For a general overview of the science
included please see the
science overview
page. This site also includes a browsing tool to explore and download
the spectra and photometry of the models, an interpolation tool to
derive spectra and photometry for values in between the sample
parameters and a fitting tool. The fitting tool includes the capacity
to fit multiple spectroscopic and photometric data types and returns
best fitting models alongside uncertainties and statistical analysis
of the fits.
In Mayne and
Harries (2010) we investigate the effects of accretion and disc
presence on the spectral and photometric characteristics of brown
dwarfs. In particular we examine the reliability of mass, age and
disc fraction derivation, and selection biases affecting mass to
accretion rate relationships. The fitting and interpolation tools are
introduced and used to explore the performance of the grid in Mayne,
Harries, Rowe & Acreman (2012).
Grids available:
For the
browser,
isochrone,
interpolation and
fitting tools two grids of models are available. These
grids are explained in detail
here. Essentially the "Ad-hoc Grid" covers a parameter space
designed to explore the effects of accretion on the variable dust
sublimation and vertical structure of the disc (
Mayne and
Harries, 2010). Whereas the "Semi-emp" covers a wider range of
ages and masses but adopts simplifications such as analyticaly
prescribed disc structures.
Contact and Referencing
To request extra detail or content for this website (e.g. extra
filter sets, parameters or different stellar models) please
email:
nathan@astro.ex.ac.uk
Navigation
- Fitting tool:[FIRST VERSION] a
tool providing best fitting models, with uncertainties and degeneracy
analysis for SED and/or photometric magnitude
observations.
- Interpolation
tool: a tool allowing linear intepolation for values
between grid points in our parameter space (and adjustment by
distances and reddenings).
- SEDs, Monochromatic
Fluxes & Magnitudes: a browsing tool allowing you to
plot the spectra and monocromatic fluxes of a given model, and
retrieve the selected data, i.e. the SED, monochromatic fluxes
or magnitudes.
- Isochrones and Mass
Tracks: a tool allowing you to select, and
download, isochrones or mass tracks constructed from the
magnitudes and colours presented in Mayne
and Harries (2010).
- Calibration and
Convergence Information: details of the physical
assumptions made, photometric systems adopted (i.e. filter
responses and zero points etc) and the parameter space covered
(i.e. models which have converged).
- Disc
Structure: a description of the importance of the
disc structure on the resulting SEDs.
- Classification of
Accreting Brown Dwarf Disc systems: a description
of some of our main results, detailing the effects of disc
presence and accretion on classification of brown dwarf
systems. Subsequently leading to unreliability in the derived
quantities, such as age and mass, and selection affects
involving mass to accretion rate relations.
- Disc
Fractions: a study of disc fraction estimates for our
model grid, including suggested cuts for selecting brown dwarf
systems with discs.
- Science Overview: a brief
description of the science behind the available data, meant
for a general audience. For a more in depth description of
this work please refer to Mayne
and Harries (2010) and Mayne,
Harries, Rowe & Acreman (2012)
Want the data now?
Grid ( what does this mean?)
|
Type
|
Units
|
Contains
|
|
"Ad-hoc"
"Semi-emp"
|
SEDs
|
Angs, erg s-1 cm-2 A-1
|
SEDs-all systems
|
"Ad-hoc"
"Semi-emp"
|
SEDs
|
μm, mJy
|
SEDs-all systems
|
"Ad-hoc"
"Semi-emp"
|
Magnitudes
|
Mags
|
Magnitudes-all filters, all naked systems
|
"Ad-hoc"
"Semi-emp"
|
Magnitudes
|
Mags
|
Magnitudes-all filters, all disc systems
|
"Ad-hoc"
"Semi-emp"
|
Fluxes
|
μm,erg s-1 cm-2 A-1
|
Monochromatic fluxes-all filters, all naked systems
|
"Ad-hoc"
"Semi-emp"
|
Fluxes
|
μm,mJy
|
Monochromatic fluxes-all filters, all naked systems
|
"Ad-hoc"
"Semi-emp"
|
Fluxes
|
μm,erg s-1 cm-2 A-1
|
Monochromatic fluxes-all filters, all disc systems
|
"Ad-hoc"
"Semi-emp"
|
Fluxes
|
μm,mJy
|
Monochromatic fluxes-all filters, all disc systems
|
"Ad-hoc"
"semi_emp"
|
Properties of all disc models
|
Various
|
Properties of all the disc models e.g. inner edge radius and temperature etc.
|
All .tar.gz files contain a README file explaining file names, and
all individual files contain header lines preceded by # explaining
content.
