COMMISSION 27 OF THE I.A.U.
      INFORMATION BULLETIN ON VARIABLE STARS
                  Number 2404

                                  Konkoly Observatory
                                  Budapest
                                  26 September 1983

                                  HU ISSN 0374-0676


      IQ Vel: IMPROVED LIGHT-CURVE PARAMETERS

   The eclipsing binary IQ Vel was discovered in April 1978
at the European Southern Observatory, La Silla, Chile (Kohoutek, 
1979). We have continued to observe this star in 1979 and
1982 at the ESO using again the 50 cm telescope and a pulse
counting photometer (EMI 6256 A photomultiplier) and we made
174 UBV measurements. Stars in the E-regions (Cousins, 1973;
Vogt, et.al., 1981) served as photometric standards.
   Our photometry is consistent with that made in 1978:for
the comparison star No.1 we found in 1982: V =12.404, B-V =
+0.547, U-B = +0.053 ( n = 23); the brightness of the variable
star outside eclipse was: V =12.812, B-V = +0.294, U-B =
+0.174 ( n = 8 ).
   Three primary and two secondary minima were recorded
having parameters summarized in Table I (a graphical method

            Table I Observed minima


Min.hel.JD Min.   Eclipse depth             Eclipse
                     V         B       U    duration
------------------------------------------------------
2443940.5489   I    0.92m     0.98m     -       -   */
         +-5 m.e.
   4994.7515  II    0.110     0.086   0.078   0.24d
         +-5 m.e.
   4996.7212   I    0.910     0.977   0.947   0.24
         +-2 m.e.
   4998.6885  II    0.120     0.099   0.093   0.24
         +-5 m.e.
   5000.6477   I    0.920     0.981   0.952   0.24
         +-2 m.e.
------------------------------------------------------
*/ observed by U. Haug

was used for determining the times of the minima), Combining
the five primary minima in the period 1978-82 (for the minima.
observed in 1978 see Kohoutek, 1979) the following elements
of the light-curve could be derived:

    Min.hel.I = JD 2444996.72137 + 3.9262974d * E
                            +-14         +-6 m.e.
  
  The secondary minima of 1982 are placed at phase 0.498
and 0.501, respectively, confirming a circular orbit of the
binary. The eclipse depth and duration are comparable with
those observed in 1978. Also the parameters of the binary system 
are similar to the preliminary values published earlier.
The detailed analysis of the light curve based on all available 
measurements are planned.
    I wish to thank Prof. U. Haug for kindly measuring the
minimum in 1979. The observations have been collected at the
European Southern Observatory, La Silla, Chile,





                 L. KOHOUTEK
              Hamburger Sternwarte
               D-2050 Hamburg 80
                 West Germany





References:
Cousins, A.W.J., 1973, Mem.Roy.Astron.Soc. 77, 223 [BIBCODE 1973MmRAS..77..223C ]
Kohoutek, L., 1979, I.B.V.S. No, 1532
Vogt, N., Geisse, H.S., Rojas, S., 1981, Astr.Astrophys.
    Suppl, 46, 7 [BIBCODE 1981A&AS...46....7V ]