COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2547

                                        Konkoly Observatory
                                        Budapest
                                        6 July 1984

                                        HU ISSN 0374-0676


           HR 3337 : A BRIGHT NEW ECLIPSING BINARY

   UBV photometry obtained during the first quarter of 1984 with the 10 -
inch automatic photoelectric telescope at Fairborn Observatory West in
Phoenix, Arizona shows that HR 3337 is probably an eclipsing binary.
   HR 3337 is the visual binary ADS 6828. According to Batten, Fletcher,
and Mann (1978) one component is an SB1, with P(orb.) = 5.9766d; the other
component is another SB1, with P(orb.) = 2d49955. Because the separation
between components A and B is only 0.4 arcseconds, our photometry included
both (as well as component C, 18 arcseconds away) in the diaphragm. 
According to the Yale Bright Star Catalogue, components A and B differ in
brightness by only 0.1m, the composite magnitude is V = 6.39m, and the 
composite spectral type is A5m.
   We suspected variability because Gronbech and Olsen (1976) concluded
it might be "variable in V," on the basis of the scatter in three separate
photoelectric measures. HR 3337 was included in the list of 20 suspected
variable stars published by Hall (1983).
   Our photometry is described in detail by Boyd, Genet, and Hall (1984)
and the data have been sent to the I.A.U. Commission 27 Archive for Unpublished
Observations of Variable Stars (Breger 1982), where they are available
as file no. 136. Our comparison star was HD 71297.
  When our differential magnitudes were plotted with respect to phase
computed with the ephemeris

        JD(hel.) = 2442884.158 + 2.49955d n

given by Batten, Fletcher, and Mann (1978), where the initial epoch is a time
of periastron, there was evidence of a shallow eclipse around phase 0.48p.
This phase corresponds to a time of conjunction (the spectroscopic primary  
component in front) to within about 0.05p, which is approximately the 
uncertainty to be expected in extrapolating forward to the epoch of our 
observations.
   Figure 1 is a plot of all data in the phase interval between 0.4p and 0.5p.
The arrow indicates the mean level of brightness as defined by all the other
(non eclipse) points. The eclipse we see is approximately 0.06m deep in all


                             [FIGURE 1]

 Figure 1   The arrows indicate the mean level outside eclipse. The 
 points below define the shallow secondary eclipse we have discovered.


three bandpasses, but it could be deeper if the lowest points do not define
the bottom. We obtained no data in the corresponding phase interval a half
cycle away, where the other eclipse should fall. Fekel (1978) states that
the secondary star is "late F." Therefore the eclipse we have observed, when
the (earlier) primary star was in front, must be the secondary eclipse.


                LOUIS J. BOYD
                Fairborn Observatory West
                629 North 30th Street
                Phoenix, Arizona 85008

                RUSSELL M. GENET
                Fairborn Observatory East
                1247 Folk Road
                Fairborn, Ohio 45324

                DOUGLAS S. HALL
                Dyer Observatory
                Vanderbilt University
                Nashville, Tennessee 37235

References:

Batten, A. H., Fletcher, J. M., and Mann, P. J. 1978, P.D.A.O. 15, 121. [BIBCODE 1978PDAO...15..121B ]
Boyd, L. J., Genet, R. M., and Hall, D. S. 1984, I.B.V.S., No. 2511
Breger, M. 1982, I.B.V.S. No. 2246.
Fekel, F. C. 1978, B.A.A.S. 10, 660. [BIBCODE 1978BAAS...10..660F ]
Gronbech, B. and Olsen, E. H. 1976, Astr. Astrophys. Suppl. 25, 213. [BIBCODE 1976A&AS...25..213G ]
Hall, D.S. 1983, I.A.P.P.P. Comm. No. 13, 6. [BIBCODE 1983IAPPP..13....6H ]


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