COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2674

                                  Konkoly Observatory
                                  Budapest
                                  27 February 1985

                                  HU ISSN 0374 - 0676




          IS CD HERCULIS = BD + 46d 2308 VARIABLE?

   To clarify the behaviour of the variable star CD Her = BD + 46d2308 Dr.
Samus' (Moscow) asked us to observe this star photoelectrically and on the
Sonneberg plate material.
   Discrepancies in the existing papers concerning both the identification
and the spectral type were already discussed by Samus' (1984).
   Previous observations made on the photographic plates of the Babelsberg
Observatory by Prager (1931) showed irregular variations in the range of
11.2m ... 12.5m. To confirm these observations Kroll (1983) estimated the
star on the same plates used by Prager (which are now at Sonneberg) and on
plates of the Sonneberg Sky Patrol. He also found variations between 11.3m
and 12.5m. A search for a hidden period was not successful.
   In order to get more accurate data I observed CD Her photoelectrically
in U, B and V with the Sonneberg 60 cm mirror II during 17 nights in 1984.
Only small variations of some hundredth of a magnitude were visible (see
the Table). If these are real, they are nevertheless too small to confirm
the estimations by Prager and Kroll. The cause of this discrepancy is as yet
unclear.


Table. Photoelectric observations of CD Her

J.D.            DeltaV     DeltaB  DeltaU
-------------------------------------------
2445780         -0.02m     -0.10m  -
   5782          0.00      -0.01   -
   5783         -0.05       -      -
   5810         -0.01       -      -
   5822         -0.01       -      -
   5890         -0.02      -0.09   -0.16m
   5903         -0.03      -0.08   -
   5912         -0.01      -0.10   -
   5913         -0.04      -0.07   -
   5916         -0.04      -0.10   -0.13
   5925         -0.02      -0.07   -0.15
   5926         -0.02      -0.10   -0.17
   5930         -0.02      -0.10   -
   5935         -0.05      -0.09   -0.10
   5936         -0.05      -0.11   -
   5944         -0.03      -0.05   -
   5946         -0.03      -0.03   -
-------------------------------------------


   The magnitude differences are in the sense CD Her minus comparison star,
which is situated 7.7' NW of the variable (see the finding chart given by
Samus' (1984)). In addition, the red star Z of that chart has been checked
occasionally; 10 observations also do not point to any significant variability.




                          R. LUTHARDT

                        Sternwarte Sonneberg
                        Zentralinstitut fur
                        Astrophysik der
                        Akademie der Wissenschaften 
                        der DDR





References:

Prager, R., 1931, Astr. Nachrichten, 243, 366. [BIBCODE 1931AN....243..359P ]
Kroll, P., 1983, private communication.
Samus, N.N., 1984, Astron. Tsirk., No. 1315, p. 3. [BIBCODE 1984ATsir1315....3S ]