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J/A+A/441/685  HeI & HeII radial velocities of Sk 160/SMC X-1 (Val Baker+, 2005)
The mass of the neutron star in SMC X-1.
    Val Baker A., Norton A.J.,  Quaintrell H.
   <Astron. Astrophys. 441, 685 (2005)>
   =2005A&A...441..685V
ADC_Keywords: Binaries, X-ray ; Stars, supergiant ; Radial velocities ;
              Spectroscopy
Keywords: binaries: close - stars: neutron - stars: individual: SMC X-1 -
          stars: individual: Sk 160 - stars: fundamental parameters

Abstract:
    We present new optical spectroscopy of the eclipsing binary pulsar Sk
    160/SMC X-1. From the He I absorption lines, taking heating
    corrections into account, we determine the radial velocity
    semi-amplitude of Sk 160 to be 21/8±1.8km/s. Assuming Sk 160 fills
    its Roche-lobe, the inclination angle of the system is
    i=65.3±1.3° and in this case we obtain upper limits for the mass
    of the neutron star as Mx=1.21±0.10M☉ and for Sk 160 as
    Mo=16.6±0.4M_☉.

Description:
    This Table lists the raw and heating corrected HeI absorption line
    heliocentric radial velocity data for Sk 160 resulting from
    August/September 2000 observations at SAAO. Also listed are the
    heliocentric radial velocities measured from the HeII 4686Å
    emission line.
Objects:
    ----------------------------------------------------------
       RA   (2000)   DE       Designation(s)
    ----------------------------------------------------------
    01 17 05.1   -73 26 36    Sk 160 = X SMC X-1
    ----------------------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2.dat        32       56   HeI absorption line & HeII emission line
                             heliocentric radial velocity data for Sk 160


Byte-by-byte Description of file: table2.dat

   Bytes Format Units   Label    Explanations

   1-  9  F9.3  d       MJD      Modified Julian Date (JD-2400000.5) 
                                 of each observation
  11- 15  F5.3  ---     Phase    [0/1] Orbital phase of each observation (ecl=0)
  17- 19  I3    km/s    HRVHeI   Heliocentric HeI absorption line raw RVs
  21- 22  I2    km/s   e_HRVHeI  rms uncertainty in each RV
  24- 26  I3    km/s    HRVHeIc  Heating corrected heliocentric HeI RVs
  28- 31  I4    km/s    HRVHeII  ? Heliocentric HeII emission line RVs


Acknowledgements: A.J. Norton, a.j.norton(at)open.ac.uk

(End)                                        Patricia Vannier [CDS]  13-Jul-2005