Brown dwarfs, "stars" that don't achieve core fusion of hydrogen to helium, have masses between the lightest "proper" stars and the heaviest planets. Unlike the spectra of red dwarfs stars that exhibit absorption bands of metal oxides (titanium and vanadium) L dwarfs have strong metal hydride bands and clear alkali metal lines. In the near infrared there are absorption bands of water and carbon monoxide.
On the other hand in the infrared T dwarfs have absorption bands of methane and collision induced absorption results in them having a blue near infra-red colour.
IDENTIFICATION OF T DWARF CANDIDATES IN THE WISE RESULTS
PRIMARY SOURCES
The First Ultra-Cool Brown Dwarf Discovered by the Wide-field Infrared Survey Explorer (Mainzer et al 2010) - link
SECONDARY SOURCES
Ultracool Field Brown Dwarf Candidates Selected at 4.5 microns (Eisenhardt et al 2010 - link
FILTERING THE CANDIDATES
RESULTS - PART 1
Download details of the candidates from here.
IDENTIFICATION OF L AND T DWARF CANDIDATES IN THE SDSS AND WISE RESULTS
PRIMARY SOURCES
Ultra-cool dwarfs: new discoveries, proper motions, and improved spectral typing from SDSS and 2MASS photometric colors (Zhang et al 2009)- link
SECONDARY SOURCES
Benchmark ultra-cool dwarfs in widely separated binary systems (Zhang et al 2010) - link
FILTERING THE CANDIDATES
An initial target list was obtained by downloading all SDSS stars where (r-i) is between 0.62 and 2.61 and (i-z) is between 1.99 and 4.74. These objects were then used to create an input file for the WISE database and the results obtained filtered as indicated below.
RESULTS - PART 2
Download details of the candidates from here.
Download details of the rejected candidates from here.
The next stage would be to look at candidates where where (r-i) is between 0.62 and 2.61 or (i-z) is between 1.99 and 4.74.
Over the last few years I have carried out many astronomical data mining or data analysis projects. Most remain unpublished and this series of papers aims to put them all into the public domain. I welcome constructive feedback from readers and encourage colleagues to take the work forward, perhaps as far as peer reviewed publication. I can be contacted by email. and this address is monitored daily.
Martin Piers Nicholson - Shropshire, United Kingdom.
This page was last updated on July 19th 2011.