Table information for 'hdgaia.main'

General

This table is available for ADQL queries and through the TAP endpoint.

Resource Description: This is the Henry Draper catalog (HD, Cannon & Pickering 1918-1924) as distributed by the Astronomical Data Center in 1989 (Vizier III/135A), with Gaia DR2 source_ids and positions added. The link to modern Gaia DR2 was done through Fabricius et al's match between HD and Tycho 2 (Vizier IV/25), TGAS to match Tycho 2 and Gaia DR1, and Gaia DR2 to match against Gaia DR1.

For a list of all services and tables belonging to this table's resource, see Information on resource 'The Henry Draper Catalog with Gaia IDs'

Further information

This resource grew out of the realisation just how hard it is to do useful things with HD numbers in the VO. In provides the original Henry Draper catalog together with Gaia DR2 source ids for the stars identified in Fabricius et al's Tycho 2-HD match (2002A&A...386..709F)

It was generated as follows (cf. sources):

  1. create a database table for the HD catalog with empty columns for the Gaia counterparts. While doing this, precess the B1900 positions to J2000. We haven't bothered with diffrences in the reference catalogs; at the 1 arcminute precision of the HD, this doesn't matter at all. All astrometry coming from HD is for debugging only.

  2. Get a mapping from HD numbers to standard Tycho-2 ids from VizieR:

    select HD, n_HD, n_TYC,
      TYC1 || '-' || TYC2 || '-' || TYC3 as tycho_id
    from "IV/25/tyc2_hd"
    
  3. Turn the Tycho 2 identifier to a Gaia DR2 source_id using the dr2_tycho_best_neighbour table. It does not exist on VizieR, so we used the ARI-Gaia service:

    select hd, n_hd, n_tyc, source_id
    from gaiadr2.tycho2_best_neighbour
    join TAP_UPLOAD.tyc
    on (tycho_id=original_ext_source_id)
    

    After this procedure, HD 45900, HD 260686, and HD 121169 did not have unique matches. It seemed excessive to complicate the data model just for these three objects. We have randomly dropped one possible match for each of them; in addition, HD 121169 should have had an second match, which did not work out in Gaia DR2. These doubtful cases can be identified by n_TYC=2.

  4. Complete the source_id, gaia_ra, gaia_dec, n_hd, and n_tyc columns of the table created in step (a) with the data obtained in step (c) and a local DR2 table.

Citing this table

This table has an associated publication. If you use data from it, it may be appropriate to reference 1924AnHar..99....1C (ADS BibTeX entry for the publication) either in addition to or instead of the service reference.

To cite the table as such, we suggest the following BibTeX entry:

@MISC{vo:hdgaia_main,
  year=2018,
  title={The Henry Draper Catalog with Gaia IDs},
  author={Cannon, A.J. and Fabricius, C. and Demleitner, M.},
  url={http://dc.zah.uni-heidelberg.de/tableinfo/hdgaia.main},
  howpublished={{VO} resource provided by the {GAVO} Data Center}
}

Fields

Sorted by DB column index. [Sort alphabetically]

NameTable Head DescriptionUnitUCD
hd Hd HD number for this object N/A meta.id;meta.main
dm DM Durchmusterung identifier, taken either from the Bonner Durchmusterung (BD), Cordoba Durchmusterung (CD), or Cape Photographic Durchmusterung (CPD); stars not given in any of them are referenced by their AGK number. [Note d] N/A meta.id.cross
ra_orig Ra_orig Original right ascension for equinox J1900.0. Note that this position is only good to about an arcminute. N/A pos.eq.ra
dec_orig Dec_orig Original declination for equinox J1900.0. Note that this position is only good to about an arcminute. N/A pos.eq.dec
ra_orig_2000 Ra_orig_2000 Original right ascension for equinox J2000.0 (precession done by DC staff). Note that this position is only good to about an arcminute. N/A pos.eq.ra
dec_orig_2000 Dec_orig_2000 Original declination for equinox J2000.0 (precession done by DC staff). Note that this position is only good to about an arcminute. N/A pos.eq.dec
mv_meas m_V? '0' if the m_v is a measured value, '1' if it's a value inferred from m_pg and the spectral type. N/A meta.code
m_v m_V Photovisual magnitude or the star, except for magnitudes >= 20, which are object type flags (see note). [Note m] mag phot.mag;em.opt.V
mv_comb Comb? C if m_v is a combined magnitude (with a neighbouring star given in this catalogue), NULL otherwise. N/A meta.code
mpg_meas Meas? '0' if the m_pg is a measured value, '1' if it's a value inferred from m_v and the spectral type. N/A meta.code
m_pg m_pg Photographic magnitude or the star, except for magnitudes >= 20, which are object type flags (see note). [Note m] mag phot.mag;em.opt.B
mpg_comb Comb? C if m_pg is a combined magnitude (with a neighbouring star given in this catalogue), NULL otherwise. N/A meta.code
spectral Spectral Spectral type, given in upper and lower case as in the published catalog. N/A src.sptype
pg_intensity Intensity Photographic intensity of the spectrum estimated by Annie Cannon. The faintest spectra which could be classified with certainty were assigned a value of 1, while the densest are given as 10. For stars having two intensities in the published catalog, only the first is given here. N/A meta.code.qual
remarks Rem Remarks. See note for what the letters mean. [Note r] N/A meta.code
n_hd #HD Number of HD stars matched to a Tycho 2 source by Fabricius et al, 2002A&A...386..709F. N/A meta.number
n_tyc #Tyc Number of Tycho 2 stars matched to a HD source by Fabricius et al, 2002A&A...386..709F. N/A meta.number
source_id Gaia source_id Gaia DR2 source_id matching the HD object through Fabricius' Tycho 2 match and Gaia DR2's tycho2_best_neighbour. For four ambiguous matches, a unique match was randomly chosen (see reference URL). N/A meta.id.cross
gaia_ra RA Gaia ICRS Right Ascension from Gaia DR2 (i.e., Epoch J2015.5) deg pos.eq.ra;meta.main
gaia_dec Dec Gaia ICRS Declination from Gaia DR2 (i.e., Epoch J2015.5) deg pos.eq.dec;meta.main

Columns that are parts of indices are marked like this.

Other

The following services may use the data contained in this table:

VOResource

VO nerds may sometimes need VOResource XML for this table.

Notes

More Information on the Base Resource

This resource grew out of the realisation just how hard it is to do useful things with HD numbers in the VO. In provides the original Henry Draper catalog together with Gaia DR2 source ids for the stars identified in Fabricius et al's Tycho 2-HD match (2002A&A...386..709F)

It was generated as follows (cf. sources):

  1. create a database table for the HD catalog with empty columns for the Gaia counterparts. While doing this, precess the B1900 positions to J2000. We haven't bothered with diffrences in the reference catalogs; at the 1 arcminute precision of the HD, this doesn't matter at all. All astrometry coming from HD is for debugging only.

  2. Get a mapping from HD numbers to standard Tycho-2 ids from VizieR:

    select HD, n_HD, n_TYC,
      TYC1 || '-' || TYC2 || '-' || TYC3 as tycho_id
    from "IV/25/tyc2_hd"
    
  3. Turn the Tycho 2 identifier to a Gaia DR2 source_id using the dr2_tycho_best_neighbour table. It does not exist on VizieR, so we used the ARI-Gaia service:

    select hd, n_hd, n_tyc, source_id
    from gaiadr2.tycho2_best_neighbour
    join TAP_UPLOAD.tyc
    on (tycho_id=original_ext_source_id)
    

    After this procedure, HD 45900, HD 260686, and HD 121169 did not have unique matches. It seemed excessive to complicate the data model just for these three objects. We have randomly dropped one possible match for each of them; in addition, HD 121169 should have had an second match, which did not work out in Gaia DR2. These doubtful cases can be identified by n_TYC=2.

  4. Complete the source_id, gaia_ra, gaia_dec, n_hd, and n_tyc columns of the table created in step (a) with the data obtained in step (c) and a local DR2 table.

Copyright and such: This work has made use of data from the European Space Agency (ESA) mission `Gaia `_, processed by the Gaia `Data Processing and Analysis Consortium (DPAC) `_. Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.