Skip to content
Astrophysics group
 

Accreting Brown Dwarf and Disc, Spectra and Photometry

WARNING: Upper limits may not be handled correctly. I am investigating this (the edit to the formula in the paper would be to change to 1.0-Q for the probability.

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.


Validate   Link-check © Copyright & disclaimer Privacy & cookies Share