COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3337

                                            Konkoly Observatory
                                            Budapest
                                            13 June 1989

                                            HU ISSN 0374 - 0676


           SAO 139 174 IS AN ECLIPSING BINARY STAR


SAO139174 (BD -1d2777 = HD 114125) was used as a check star during the
observations performed on 18 and 19 March 1988 at Sierra Nevada Observatory in
Spain. The star showed brightness variations which suggested that it might be
an eclipsing binary (Rodriguez et al., 1988).

During 18 nights, from March 21 to April 22, 1989, SAO 139174 was observed
using a solid state photometer attached to the Cassegrain focus of the 0.5 m
Mons telescope at Observatorio del Teide (Instituto de Astrofisica de Canarias
Canary Islands, Spain).

SAO 139171 was used as comparison 1, and SAO 139131 (48 Vir) as comparison
2, while SAO 139086 (44 Vir), SAO 139139, SAO 139186, and SAO 139196 as check
stars.


                              [FIGURE 1]


The results of this surveillance program proved that SAO 139174 is an eclipsing
binary star with a period close to 2.73 days. The star is a 7.81 magnitude (V)
object at the maximum light that fades to 8.10 and 8.05 at the primary and
secondary minima respectively. The eclipses last about 6.3 hours. Figure 1
shows the light curve obtained.

From our set of data we computed the tentative ephemeris for the primary
minimum:

HJD = 2447240.97128 + 2.73236d E
          +-0.00006 +-0.00002

After a quick first analysis of the light curve using the Russell-Merrill
model according to Irwin (1962) we obtained the following elements:

R_s=0.15   L_s=0.423
R_g=0.19   L_g=0.577
i=80.1deg

Additional photometric data are needed in order to compute more precise
elements and ephemeris for this new binary system.

We would like to acknowledge the Instituto de Astrofisica de Canarias for
allowing us to utilize their facilities. We would like to acknowledge also
C. Gallart for her assistance in the observation during some nights, and E.
Garcia-Melendo for his help in computing the elements of the system.


R. CASAS ^1^2 and J.M. GOMEZ-FORRELLAD ^1

^1 Grup d'Estudis Astronomics
   Apartat 9481
   08080 Barcelona, Spain
^2 Instituto de Astrofisica de Canarias
   38200 La Laguna, Tenerife, Spain

References:

Rodriguez, E., Sedano, J.L., Lopez de Coca, P., and Rolland, A. 1988, 
   Inf. Bull. Var. Stars, No. 3174.
Irwin, J.B. 1962, in "Astronomical Techniques", Univ. of Chicago Press, p. 584. [BIBCODE 1964aste.book..584I ]