SIMBAD: Description of measurement types

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Appendices. Collections of measurements in SIMBAD

Measurements in SIMBAD contain various original observing data collected from the literature, as well as some historical compilations (e.g. GCVS, GCRV, or PLX catalogues).

  • Diameter:
    Stellar diameters, see 2001A&A...367..521P for an explanation of the coding of the methods of measurements.

  • Distance :
    Applies to any astronomical object, galactic or extragalactic. Please check the unit, which can be pc (galactic stars), kpc, or Mpc (galaxies), especially to make selections on criteria.

  • Fe/H :
    Historically devoted to stars, this measurement contains Teff, logg, and Fe/H. However we also collect the metallicity of other astronomical objects in this section. Note that FeI/H, FeII/H, and M/H are not collected.

  • SpT :
    Spectral types from UV, optical, or infrared spectroscopy. Spectral types estimated from photometric observations only are not collected. (Formerly named MK, standing for Morgan & Keenan classification)

  • Plx :
    Trigonometric parallaxes

  • PM :
    Proper motions

  • Rot :
    Stellar rotational velocities (vsini)

  • Var :
    Devoted to variable stars. Contains the classification as given by the authors, maximum and minimum magnitudes, photometric band of the measurements, and period. (Formerly named V*)

  • Velocities :
    Applies to any astronomical object, galactic or extra- galactic. Lists heliocentric velocities, or LSR velocities, or cz, or redshifts. Please check the flag type which can be v, lsr, z, or cz, especially to make selections on criteria.
See More details on each data.


Historical and obsolete measurements

  • Historical catalogues :

    Some catalogues were ingested in SIMBAD in a measurement section before the birth of the VizieR database. Since then they have been included in VizieR. Therefore they have been removed from SIMBAD to avoid an unuseful duplication of data. The following historical catalogues can be accessed directly in VizieR from a SIMBAD page by clicking on the VizieR icon next to the name : CEL, cl.g (name ACO), Einstein (name 2E), GJ, HGAM, IRAS, IRC, JP11, SAO, TD1, as well UBV and hbet (name GEN#), and uvby(1) (name uvby98).

  • Velocities and redshifts :

    There were 5 different measurements in SIMBAD to collect heliocentric velocities, cz, and redshifts : orv, rvel, GCRV, z, and ze. All these data have been transfered into the new and unique Velocities measurement. Note however that, unfortunately, there was no field to record the measurement uncertainty in some old measurements.

  • Photometry :

    In general, to get as many photometric data as possible on a given object from its SIMBAD page, we recommand to use the photometry viewer. Do not forget however that this is just a Xmatch within a search radius; it does not guarantee that all the data actually apply to the same source.


Observing logs in SIMBAD

put in SIMBAD at the request and in collaboration with the consortia

  • Herschel :
    Herschel Space Observatory

  • ISO :
    Infrared Space Observatory

  • IUE :
    International Ultraviolet Explorer

  • XMM :
    X-ray Multi-Mirror Mission

Last realease of this documentation : 2021-05-10

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