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PLEIADXRAY - ROSAT PSPC Catalog of the Pleiades (Micela et al. 1996)

HEASARC
Archive

Overview

This catalog contains the results of a deep X-ray survey of the core region of the Pleiades open cluster carried out with ROSAT. In a single PSPC field (~1 degree in radius), 99 of 214 Pleiades stars are detected in X-rays, and upper limits are computed for the remainder. This catalog lists the characteristics of these stars taken from the literature, including their rotational data, as well as their X-ray characteristics. The nucleus of the composite catalog used in this study is the catalog compiled from the published literature for the Einstein investigations of the Pleiades (Micela et al. 1990, ApJ, 348, 557). This list has been extended by the results of recent surveys to a completeness limit of visual magnitude of about 18.

Catalog Bibcode

1996ApJS..102...75M

References

ROSAT Observations of the Pleiades. I. X-Ray Characteristics of a Coeval
Stellar Population
    Micela G., Sciortino S., Kashyap V., Harnden F.R., Rosner R.
   <Astrophys. J. Suppl. 102, 75 (1996)>
   =1996ApJS..102...75M

Provenance

This database was created at the HEASARC in April 2002 based on the ADC/CDS Catalog J/ApJS/102/75 and is derived from Tables 1 and 5 of the published paper.

Parameters

Micela_Number
A running number in order of increasing Right Ascension.

Name
The star designation as listed in the reference. Notice that the prefixes of these names are typically not in the standardized system as used, for example, by Simbad. To convert them to their Simbad equivalents, one typically should add 'Cl* Melotte 22 ' in front of these names. For the convenience of users of this table, the HEASARC lists below a concordance of the names used in this table with their Simbad equivalents:

  Name in Table     Simbad Equivalent

      A #            not in Simbad
      ALR #          Cl* Melotte 22 ALR #
      B #            Cl* Melotte 22 B #
      Hz #           Cl Melotte 22 #
      HCG #          Cl* Melotte 22 HCG #
      JRS #          not in Simbad
      MT #           Cl* Melotte 22 MT #
      SK #           Cl* Melotte 22 SK #
      T #            not in Simbad
      VM #           Cl* Melotte 22 VM #
  

RA
The Right Ascension of the Pleiades star in the specified equinox. In the original table, the RA was given in equinox 2000 and with a precision of 0.1 seconds of time.

Dec
The Declination of the Pleiades star in the specified equinox. In the original table, this was given in equinox 2000 and with a precision of 0.1 arcseconds.

LII
The Galactic Longitude of the Pleiades star.

BII
The Galactic Latitude of the Pleiades star.

Vmag
The V magnitude of the Pleiades star.

Ref_Vmag
A code for the reference for the V Magnitude: the key is given in ftp://cdsarc.u-strasbg.fr/pub/J/ApJS/102/75/refs.dat.gz

BV_Color
The B-V color of the Pleiades star.

Spect_Type
The spectral type of the Pleiades star.

Ref_Spect_Type
A code for the reference for the spectral type: the key is given in ftp://cdsarc.u-strasbg.fr/pub/J/ApJS/102/75/refs.dat.gz

Limit_Vsini
This parameter is set to '<' to indicate an upper limit for the projected rotation velocity, v sin(i).

Vsini
The projected rotation velocity, v sin(i), in km/s, where v is the actual rotation velocity and i is the inclination angle.

Remarks
Some concise remarks on the binarity, variability, flare star nature, and/or alternate names of the Pleiades star.

Ref_Remarks
A code for the reference for the source for the remarks: the key is given in ftp://cdsarc.u-strasbg.fr/pub/J/ApJS/102/75/refs.dat.gz

Extinction_Flag
This parameter is set to 'Y' to indicate a value of the (B-V) reddening E(B-V) > 0.1.

Offset_RA
The X-ray to optical position offset in the Right Ascension direction, in arcseconds, for stars detected as X-ray sources with EXSAS or PROS that do not belong to complexes of overlapping sources.

Offset_Dec
The X-ray to optical position offset in the Declination direction, in arcseconds, for stars detected as X-ray sources with EXSAS or PROS that do not belong to complexes of overlapping sources.

Offaxis
The off-axis angle of the star, in arcminutes, i.e., the difference between the center of the ROSAT PSPC FOV and the stellar position.

Limit_Count_Rate
This parameter is set to '<' to indicate an upper limit for the PSPC count rate.

Count_Rate
The PSPC count rate of the X-ray source, in ct/s (converted by the HEASARC from the units of ct/ks in the original table).

SNR
The signal-to-noise ratio of the X-ray source, i.e., the number of sigma.

Hardness_Ratio
The hardness ratio of the X-ray source, defined as the ratio of the counts in the 0.2 to 0.9 keV band to those in the 0.9 to 2.01 keV band. The values of the hardness ratio were individually corrected for the vignetting energy dependence and for nonuniformities of the PSPC using the values of the exposure map at the source positions in the various energy bands considered.

Hardness_Ratio_Error
The mean error in the X-ray hardness ratio.

Conversion_Factor
The Counts-to-Energy Conversion Factor (CCEF), in units of 10^-11 erg/cm^2/count = 10^-14 W/count, i.e., the number which the count rate has been multiplied by to convert it to the source flux in the 0.16 to 4.0 keV bandpass.

Limit_Log_Lx
This parameter is set to '<' to indicate an upper limit for the (logarithm of the) X-Ray Luminosity, log L(X).

Log_Lx
The logarithm of the X-Ray luminosity, log L(X), in erg/s, in the 0.16 to 4.0 keV bandpass, computed for an assumed distance of 127 pc. For the stars B 203 and Hz 2366 the X-ray luminosities are quoted as upper limits, since the authors attribute the emission from the detected sources to different counterparts.

Multiple_Cpt_Flag
This parameter has a non-blank value to indicate X-ray sources that have been identified with more than one star or are in complexes of overlapping sources. Stars with the same value for this parameter are identified with the same X-ray source.

Class
The HEASARC browse classification, derived from the value of the spectral type parameter.


Contact Person

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

Page Author: Browse Software Development Team
Last Modified: 23-Mar-2006