MWDD contains only the information found in the Tables (and sometimes in the text) of the papers listed in the References section. One file (in .csv format) was created for each paper included in the database. This file contains various columns, one for each variables that one wish to include (see list below), that contains all the information concerning each stars in that paper. Since a star can be published under many different names, each star is assigned a unique identifier via Simbad. If a star is entered in different papers under different names, the entries will be merged together in the database.

The table and the charts show the most recent value of each variable of each stars.

See: How to include a new paper in MWDD

List of variables

Variable's names are case sensitive. Leave field blank if information is unavailable or unknown.

Variable Type Description Notes
ads String URL adress of the article ads page for this entry. Can also be a link to a website like Simbad or SDSS if the information is from there. 1
age float Cooling age of the star, in Gyr.
allnames String All names associated to a star, separated by a semicolon.
BD float Dipole magnetic field strength, in megagauss.
BDinc float Dipole magnetic field inclination, in degrees.
binarity String If is a binary system. Can be 'WDMS' if the system is made of a white dwarf and a main sequence star, 'DDu' if it is an unresolved double degenerate and should be counted as two stars, or 'DDr' if it is a resolved double degenerate and should be counted as one star (wich means its companion might have its own entry).
comp String Athmosphere composition of the star, can be 'H', 'He', 'C', etc. Leave blank if unknown.
D[X] float Error on variable [X].
date other Date, format YYYY.MM, of the article where the information comes form. 1, 3
Dpc float Distance, in parsec.
fiber integer SDSS fiber number, concern only the SDSS spectrum. 2
hasdisk String Write 'yes' if the star has an infrared excess (disk).
icrsdec float Declination in the International Celestial Reference System, in degrees (J2000).
icrsra float Right ascention in the International Celestial Reference System, in degrees (J2000).
ismag String Write 'yes' if the star is magnetic.
logg float Log of surface gravity, in cm/s2.
log[x]h float/String Abundance of [x] element compared to hydrogen, all in lower case (ex: logcah). 4
log[x]he float/String Abundance of [x] element compared to helium, all in lower case (ex: logcahe). 4
mass float Mass, in solar mass.
mjd integer Modified Julian Date, indicates when the observation was carried out by SDSS. 2
Mv float Absolute magnitude.
parallax float Parallax, in mas.
pm float Proper motion in mas/year (paired with pmangle).
pmangle float Proper motion angle (paired with pm).
pmdec float Declination proper motion, in mas/year (paired with pmra).
pmra float Right ascention proper motion, in mas/year (paired with pmdec).
plate integer An integer indicating which SDSS plug plate was used to collect the SDSS spectrum. 2
name String Alternative name for the star.
source String Article (or other source) where the information comes from, format Author et al. YYYY. 1
spectype String Spectral type. Most common are 'DA', 'DB', 'DC', 'DQ', 'DZ', 'DO and 'PG1159'. Can also be complex, for example 'DBAZ' or 'DA+dM'.
teff float Effective temperature, in kelvin.
variability String If the star is pulsating. Can be 'VAR' if the star is confirmed pulsating, 'NOV' (not observed to vary) if it is confirmed not pulsating. Leave blank unknown or uncertain.
velU float Velocity U, in km/s.
velV float Velocity V, in km/s.
velW float Velocity W, in km/s.
wdid String Unique identifier of the star. 1
wdname String White dwarf name, format WD xxxx+xxx.
B, V, R ,I , J, H, K float Magnitudes.
su, sg, sr, si, sz float ugriz magnitudes.

Notes

  • 1: The information is mandatory for every entry.
  • 2: Downloaded directly from SDSS. More information here.
  • 3: The date affects in wich order the information will be taken into account in the table and in the charts. They show the most recent information available for each variable.
  • 4: The database supports for a float (ex:-5.2) or a float preceded by '<' indicating an upper limit (ex:<-7.1) .





The Montreal White Dwarf Database is produced and maintained by Prof. Patrick Dufour at Université de Montréal. Please send database updates, corrections, suggestions or bug reports to dufourpa@astro.umontreal.ca.