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PPM - Positions and Proper Motions Catalog

HEASARC
Archive

Overview

The PPM database is the Catalog of Positions and Proper Motions. It combines the two catalogs for PPM North and PPM South, the Bright Stars Supplement to PPM, and the 90,000 Stars Supplement to the PPM. The PPM North list gives positions and proper motions of 181731 stars north of -2.5 degrees declination. PPM South gives positions and proper motions of 197179 stars south of about -2.5 degrees declination. The star density of PPM South is slightly higher than that of its northern counterpart and the accuracy of the present-epoch positions is roughly twice that in the north.

A number of bright stars are missing from the PPM and PPM South Star Catalogs. The Bright Stars Supplement included here makes the PPM catalogs complete down to V=7.5 mag. For this purpose it adds all missing stars brighter than V=7.6 mag that could be found in published star lists. Their total number is 321. Only 5 of them are brighter than V=3.5

Since its appearance in 1966, the SAO Catalogue has been the primary source for stellar positions and proper motions. Typical values for the rms errors are 1 arcsec in the positions at epoch 1990, and 1.5 arcsec/century in the proper motions. The corresponding figures for the AGK3 Catalog in the northern hemisphere are 0.45 arcsec and 0.9 arcsec/century. Common to both of these catalogues is the fact that proper motions are derived from two observational epochs only, and that positions are nominally in the B1950/FK4 coordinate system.

The PPM Star Catalogue (Roeser and Bastian, 1991, Bastian et al., 1993; for a short description see Roeser and Bastian, 1993) effectively replaced these catalogues by providing more precise astrometric data for more stars on the J2000/FK5 coordinate system. Compared to the SAO Catalogue the improvement in precision is about a factor of 3 on the northern and a factor of 6 to 10 on the southern hemisphere. In addition, the number of stars is increased by about 50 percent. Typical values for the rms errors on the northern hemisphere are 0.27 arcsec in the positions at epoch 1990, and 0.42 arcsec/century in the proper motions. On the southern hemisphere PPM is much better, the corresponding figures being 0.11 arcsec and 0.30 arcsec/century. The improvement over the SAO Catalogue was made possible by the advent of new big catalogues of position measurements and by the inclusion of the century-old Astrographic Catalogue (AC) into the derivation of proper motions. The AC contains roughly four million stars that are not included in PPM. For most of them no precise modern-epoch position measurements exist. Thus it is not yet possible to derive proper motions with PPM quality for all AC stars. But among the 4 million there is a subset of some 100,000 CPC-2 stars that are not included in PPM. These stars constitute the 90,000 Stars Supplement to PPM, and can be identified from their PPM Number having a value between 700001 and 789676.


Catalog Bibcode

1988A&AS...74..449R

References

Catalogue of Positions and Proper Motions (aka Positions and Proper Motions -
North) , S. Roeser and U. Bastian, Astronomy and Astrophysics Supplement,
74, 449. (1988).

The Introduction to PPM, S. Roeser and U. Bastian, Astronomisches
Rechen-Institut, Heidelberg, Germany, June 1989.

Positions and Proper Motions - South Star Catalogue, compiled by U. Bastian (1)
and S. Roeser (1) in collaboration with L.I. Yagudin (2) and V.V. Nesterov (3)
with contributions from D.D. Polozhentsev (2), Kh.I. Potter (2), R. Wielen (1)
and Ya.S. Yatskiv (4). (1) Astronomisches Rechen-Institut, Heidelberg,
2) Pulkovo Observatory, St. Petersburg, 3) Sternberg Institute, Moscow,
4) Kiev Observatory, Kiev. Heidelberg, 1993.

The Bright Stars Supplement to PPM, U. Bastian and S. Roeser, Astronomisches
Rechen-Institut, Heidelberg, Germany, 1993.

PPM Star Catalogue: the 90,000 Stars Supplement, S. Roeser, U. Bastian and
A. Kuzmin, Astronomy and Astrophysics Supplement, 105, 301. (1994).

Provenance

This database was updated by the HEASARC in October 1999 based on ADC/CDS catalogs I/146 (PPM - North), I/193 (PPM - South), I/206 (Bright Stars Supplement to PPM), and I/208 (90,000 Stars Supplement to PPM).

Parameters

Name
The catalog number of the star in PPM. The PPM number of the Supplement stars is a running number, starting with 400 001, and ending with 400 321.

DM_Number
Designation of the star in the Durchmusterung Catalogs: in the Bonner Durchmusterung (BD) for zones from +89 to -22 degrees, and in the Cordoba Durchmusterung (CoD) for zones from -23 to -89 degrees). Doubtful identifications are omitted (blank). The character 'x' denotes peculiar DM suffixes which are given in the List of Remarks on Individual Stars available from the HEASARC. In the Bright Stars Supplement, this is always blank.

Vmag
Photographic magnitude.

Spect_Type
Spectral type. In the Bright Stars Supplement, this is always blank.

RA
The Right Ascension of the object in the specified equinox. Notice that the equinox (and epoch) of the RA in the originating catalog was J2000, and that the HEASARC RA parameter is precessed, if necessary, from the J2000 value, with no allowance being made for proper motion. The right ascension in a form exactly as it appears in the originating catalog is given in the parameter RA_Cat.

Dec
The Declination of the object in the specified equinox. Notice that the equinox (and epoch) of the Dec in the originating catalog was J2000, and that the HEASARC Dec parameter is precessed, if necessary, from the J2000 value, with no allowance being made for proper motion. The declination in a form exactly as it appears in the originating catalog is given in the parameter Dec_Cat.

LII
The galactic longitude of the object.

BII
The galactic latitude of the object.

RA_Cat
The Right Ascension of the object in equinox and equator J2000 in hr, mins, and seconds, exactly as it appeared in the originating catalog.

Dec_Cat
The Declination of the object in equinox and equator J2000 in deg, arcmins, and arcseconds, exactly as it appeared in the originating catalog.

RA_Prop
Proper Motion in Right Ascension for epoch and equinox J2000.0, on the system of FK5, given in seconds of time per Julian year. For FK5 stars rounded FK5 data are given.

Dec_Prop
Proper Motion in Declination for epoch and equinox J2000.0, on the system of FK5, given in seconds of arc per Julian year. For FK5 stars rounded FK5 data are given.

N_Pub
Number of individual published positions used for the derivation of the position and proper motion given (cols. 5 to 8). For FK5 stars N is set to zero. In the Bright Stars Supplement, this value is always 0.

RA_Mean_Err
Mean error of Right Ascension at the mean epoch of Right Ascension, multiplied by the cosine of Declination, given in units of seconds of arc. For FK5 stars rounded FK5 data are given.

Dec_Mean_Err
Mean error of Declination at the mean epoch of Declination, given in units of seconds of arc. For FK5 stars rounded FK5 data are given.

PM_RA_Mean_Err
Mean error of proper motion in Right Ascension, multiplied by the cosine of Declination, given in milliseconds of arc per Julian year. For FK5 stars rounded FK5 data are given.

PM_Dec_Mean_Err
Mean error of proper motion in Declination, given in milliseconds of arc per Julian year. For FK5 stars rounded FK5 data are given.

Epa
Weighted mean epoch of the individual published positions used for the derivation of Right Ascension and proper motion, given in years since 1900.0. For FK5 stars original FK5 data are given.

Epd
Weighted mean epoch of the individual published positions used for the derivation of Declination and proper motion, given in years since 1900.0. For FK5 stars original FK5 data are given.

SAO
Designation of the star in the SAO Catalog. Doubtful identifications are omitted. In the Bright Stars Supplement, this is always blank.

HD
Designation of the star in the Henry Draper Catalogue. Doubtful identifications are omitted. In the Bright Stars Supplement, this is always blank.

Agk3
Designation of the star in AGK3. Doubtful identifications are omitted. This parameter not available for PPM South sources. In the Bright Stars Supplement, this is always blank.

Cpd
Designation of the star in Cape Photographic Duchmusterung. This parameter not available for PPM North sources. For the Bright Stars Supplement, this is always blank.

Notes
Notes on the individual stars are given in these columns. Notes B, P, C, and D mark objects that should preferably not be used as astrometric reference stars.

    B    bright star: do not use this object as astrometric reference star.
    P    problem case, preferably not to be used as astrometric reference star.
    C    a critical remark on this object is given in the List of Critical
         Remarks, it should not be used as astrometric refe- rence star.
    D    double star, preferably not to be used as astrometric reference star.
    H    member of the High-Precision Subset (HPS) of PPM North.
    F    member of FK5, high precision stars, mostly very bright stars.
    R    a remark on this star is given in the List of Remarks on Individual
         Stars.
    V    the magnitude is a photographic V magnitude copied from CPC-2.
  

Class
BROWSE classification type. The classification is based on the `Spect_Type` parameter, if a value is available. Otherwise the classification is left blank.


Contact Person

Questions regarding the PPM database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 8-Nov-2004