RASSASASPV - All-Sky Automatic Survey (ASAS) Photometry of ROSAT All-Sky Survey Sources

Overview

Photometric data from the All-Sky Automatic Survey (ASAS) - South (Declination less than 29 degrees) Survey have been used for the identification of bright stars located near the sources from the ROSAT All Sky Survey Bright Source Catalog (RASSBSC). In total, 6,028 stars brighter than 12.5 magnitude in the I- or the V-bands have been selected and analyzed for periodicity. Altogether, 2,302 variable stars have been found with periods ranging from 0.137 days to 193 days. Most of these stars have X-ray emission of coronal origin, but there are a few cataclysmic binaries and early type stars with colliding winds. Whenever it was possible, the authors collected data available in the literature so as to verify the periods and to classify variable objects.

The catalog includes 1,936 stars (1,233 new) considered to be variable due to presence of spots (rotationally variable), 127 detached eclipsing binary stars (33 new), 124 contact binaries (11 new), 96 eclipsing stars with deformed components (19 new), 13 ellipsoidal variables (4 new), 5 miscellaneous variables and one pulsating RR Lyr type star (blended with an eclipsing binary). More than 70% of the new variable stars have amplitudes smaller than 0.1 magnitudes, but for the star ASAS 063656-0521.0 the authors have found the largest known amplitude of brightness variations due to the presence of spots (up to Delta V = 0.8 magnitudes).

Catalog Bibcode

2012AcA....62...67K

References

ASAS photometry of ROSAT sources.
I. Periodic variable stars coincident with bright sources from the
ROSAT All Sky Survey.
    Kiraga M.
   <Acta Astron., 62, 67-95 (2012)>
   =2012AcA....62...67K

Provenance

This table was created by the HEASARC in May 2018, based on CDS Catalog J/AcA/62/67 files catalog.dat and remarks.dat.

Parameters

Asas_Name
The ASAS source designation, viz., 'ASAS Jhhmmss+ddmm.m'.

RA
The Right Ascension of the ASAS star in the specified equinox. This was not explicitly given in the original table, but was constructed by the HEASARC from the positional part of the ASAS name. The precision is thus 1 second of time.

Dec
The Declination of the ASAS star in the specified equinox. This was not explicitly given in the original table, but was constructed by the HEASARC from the positional part of the ASAS name. The precision is thus 0.1 arcminutes.

LII
The Galactic Longitude of the ASAS star.

BII
The Galactic Latitude of the ASAS star.

Offset
The angular distance Between the formal ASAS position and the related object from the Simbad database, in arcseconds. Note that 1 pixel of the ASAS detector = 14 arcseconds.

Name
The Simbad designation of the star.

SIMBAD_Type
The Simbad object type of the star. See http://simbad.u-strasbg.fr/simbad/sim-display?data=otypes for details on the Simbad classification.

PM_RA
The Simbad proper motion of the star in the Right Ascension direction, in milliarcseconds per year (mas/year).

PM_Dec
The Simbad proper motion of the star in the Declination direction, in milliarcseconds per year (mas/year).

Parallax
The Simbad heliocentric parallax of the star, in milliarcseconds.

Radial_Velocity
The Simbad radial velocity of the star, in km/s.

Eq_Li_6707a_Limit
This parameter is set to '<' if the corresponding parameter value is an upper limit rather than a measured value.

Eq_Li_6707a
The equivalent width of the Lithium line at 6707 Angstrom, in Angstroms.

Eq_Li_6707a_Flag
This parameter is set to '?' if the corresponding parameter value is considered to be uncertain.

V_Sini_Limit
This parameter is set to '<' if the corresponding parameter value is an upper limit rather than a measured value, or set to '>' if the corresponding parameter value is a lower limit rather than a measured value.

V_Sini
The Simbad projected rotational velocity (v sin i) of the star, in km/s.

V_Sini_Flag
This parameter can contain a caveat about the Simbad projected rotational velocity, with the following possible non-blank values:

     a = there are substantial differences in v sin i values found in literature
     b = data about v sin i are probably related to a companion star
     ? = considered uncertain

Visual_Companion_Flag
This parameter can contain a caveat about the presence of visual companions to the ASAS star, with the following possible non-blank values:

       - = no known visual companion
       b = blended with much fainter star or stars (information based on visual
           inspection of DSS frames - usually DSS-2-red)
       B = blended with a star or stars of comparable brightness (information
           based on visual inspection of DSS frames - usually DSS-2-red)
       c = close visual companion (visual binary) much fainter than the primary
           star (information based on SIMBAD database or literature)
       C = close visual companion of comparable brightness (information based on
           SIMBAD database or literature)

Close_Companion_Status
This parameter can contain a caveat about the presence of close or spectroscopic companions to the ASAS star, with the following possible non-blank values:

       p = photometry may indicate a close companion
       P = definitely eclipsing binary (based on photometric data)
     SB1 = spectroscopic binary (single lined)
     SB2 = spectroscopic binary (double lined)
     SB3 = triple spectroscopic systems
     SB4 = quadruple spectroscopic systems
       ? = there is no data about spectroscopic variability (no radial velocity
           measurement or single radial velocity measurement, no spectroscopic
           lines of secondary star) and there is no photometric indication of
           close companion
      no = radial velocity measurements indicate constant radial velocity (no
           close companion star detected)
       C = composite spectrum of two or more stars, but without noticeable
           changes in the radial velocity

Bmag
The Simbad B magnitude of the ASAS star.

Vmag
The Simbad V magnitude of the ASAS star.

Spect_Type
The Simbad MK spectral type of the ASAS star.

Number_Asas_Imag_Obs
The number of ASAS observations of the star in the I-band.

Asas_Imag
The ASAS mean magnitude of the star in the I-band.

Asas_Imag_Dispersion
The dispersion of the ASAS I-band measurements, in magnitudes.

Number_Asas_Vmag_Obs
The number of ASAS observations of the star in the V-band.

Asas_Vmag
The ASAS mean magnitude of the star in the V-band.

Asas_Vmag_Dispersion
The dispersion of the ASAS V-band measurements, in magnitudes.

Bol_Correction_Imag
The adopted bolometric correction for the I-band magnitude of the star. This is based on the (V-I) color (calculated from the mean I- and V-band magnitudes) using a fit to atmospheric models presented by Bessel et al. (1998, A&38;A, 333, 231) of the form BC_I = -0.08 + 1.86(V-I)- 1.33(V-I)² + 0.251(V-I)³ for values of (V-I) in the range of 0 to 1.), and a slightly changed formula given by Reid and Gilmore (1984, MNRAS, 206, 19) for values of (V-I) in the range of 1.5 to 4.6: BC_I =-0.31(V-I) + 1.03. The value of the free parameter is changed from 1.05 to 1.03 to obtain continuity with the formula for smaller values of (V-I). There are 5 stars without V-band measurements and 6 stars without I-band measurements.

Count_Rate
The ROSAT Bright Source Catalog count rate of the associated X-ray source in the 0.1-2.0 keV band, in counts per second (ct/s).

Count_Rate_Error
The uncertainty in the ROSAT Bright Source Catalog count rate of the associated X-ray source in the 0.1-2.0 keV band, in counts per second (ct/s).

Hardness_Ratio_1
The ROSAT Bright Source Catalog hardness ratio 1 (HR1), where HR1 = (H-S)/(H+S), and H and S are the counts in the 0.5-2 keV and 0.1-0.4 keV bands, respectively.

Hardness_Ratio_1_Error
The uncertainty in the ROSAT Bright Source Catalog hardness ratio 1 (HR1).

Log_Lx_Lbol
The logarithm of the ratio of the X-ray to bolometric luminosity of the source, R_x. A conversion from the count ratio and HR1 index to the flux in the 0.1-2.4 keV photon energy range is given by Schmitt et al. (1995, ApJ, 450, 392): F_x = (5.31HR1 + 8.31) * 10^-12 * CR. Here F_x is expressed in ergs/cm²/s and CR is the count rate in counts per second listed in the ROSAT catalog. This formula was derived for X-ray coronal emission, but the authors adopted it for all of the stars in this catalog. The value of R_x is calculated as F_x/F_bol where F_bol was obtained from the mean I magnitude, the bolometric correction BC_I , and the assumption that the solar absolute bolometric magnitude is equal to 4.75.

Log_Lx_Lbol_Error
The uncertainty in the logarithm of the ratio of the X-ray to bolometric luminosity of the source, R_x.

Period
The adopted period for the variability of the ASAS source, in days.

Imag_Amp
The lower limit for the maximum amplitude of the I-band variability of the ASAS source, in magnitudes.

Vmag_Amp
The lower limit for the maximum amplitude of the V-band variability of the ASAS source, in magnitudes. The amplitudes of some variable stars (especially eclipsing variables) may be underestimated due to the rejection of extreme data points.

Var_Type
Information about the photometric variability type of the ASAS source, as follows:

    ED   = detached eclipsing binary (127 stars)
    EB   = close eclipsing binary with deformed component, and unequal depths
           of eclipses (96 stars)
    EC   = contact eclipsing binary (124 stars)
    Ell  = variability due to the deformation of a star in a close binary system
           (13 stars)
    rot  = rotational variability due to the presence of spots (1936 stars)
    puls = variability due to stellar pulsations (1 star)
    msc  = the variability is difficult to interpret (5 stars)

Remarks
This field can contain the authors' remarks and data from the literature about particular objects. Information from different sources is separated by semicolons and may include:

     P_ACVS = period from ASAS Catalog of Variable Stars
     P_phot = photometric period found in the literature (i.e., from other
               sources then ACVS)
     n(vrad) = number of radial velocity measurements in cited paper
   sig(vrad) = dispersion of radial velocity measurements given in cited paper
      P_orb = spectroscopic orbital period (with K1 and K2 radial velocity
               semiamplitudes when available)
          RS = RS CVn type variable star, i.e., a coronally active evolved star
               in a close binary system
         RS? = probably an RS CVn type star (based on photometric behavior and
               X-ray data), but its binarity should be confirmed
  EW Li line = equivalent width of Li line at 6707 Angstrom
     vis bin = visual binary star with a given separation and luminosity contrast
               given by the difference in magnitudes at given band, or measured
               flux ratio at given band
         F03 = star is listed in the catalog of Fuhrmeister and Schmitt (2003,
               A&#38;A, 403, 247) and has variable X-ray emission

The full version of the references that are mentioned in this field is available at http://cdsarc.u-strasbg.fr/ftp/cats/J_AcA/62/67/refs.dat.

Class
The HEASARC Browse object classification of the star based on its spectral type.

Contact Person

Questions regarding the RASSASASPV database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:33:19 EDT