COMMISSION 27 AND 42 OF THE IAU
                   INFORMATION BULLETIN ON VARIABLE STARS
                               Number 3833

                                                         Konkoly Observatory
                                                         Budapest
                                                         19 January 1993

                                                         HU ISSN 0374 - 0676


                  THE VARIABILITY OF BD +40d5040

In the course of photoelectric photometry of comparison stars on the AAVSO
chart for TY Andromedae (AAVSO 1942), one of us (B.A.S.) noted that the  star
marked 9.2 visual magnitude was 0.4 magnitude fainter than indicated, which
was about twice the usual error for the other measured stars in this
comparison sequence. More significantly, the star was unusually red, +2.12
B-V.
   This star is BD +40d5040 = AGK +40d2437, spectral type M8 (AGK3, 1975).
Espin (1895) first noted the strongly banded spectrum with a visual
spectroscope and included this star in his list as Espin 1051. It has also
been catalogued as a double star, ADS 16659.
   BD +40d5040 is not included in the General Catalogue of Variable Stars
(Kholopov et al. 1985) the subsequent Name Lists of Variable Stars (Kholopov
et al. 1985, 1987, 1989; Kazarovets and Samus 1990), or the New Catalogue of
Suspected Variable Stars (Kholopov et al. 1982). However, a star of this type
is likely to be variable, so D.B.W. estimated its magnitude on 76 Harvard
Observatory patrol plates of the Damon blue series spanning the interval 1975
to 1989. Comparison stars with photoelectric B magnitudes were used.
   Light variations were found over the range 10.5-11.2 ptg, with observations
near maximum or minimum recurring at intervals less than about 100 days. A
Discrete Fourier Transform analysis found a weak frequency peak equivalent to
the period 72.4 days. We conclude that BD +40d5040 is a semiregular variable
with a range of 0.7m ptg and a characteristic cycle length of about 72 days.
   Some of the information in this report was obtained from SIMBAD, database of
the Strasbourg, France, Astronomical Data Center. D.B.W. wishes to thank
Dr. Martha Hazen for the opportunity to use the Harvard plate collection for
this and other variable star investigations.


               DAVID B. WILLIAMS                 BRIAN A. SKIFF
               9270-A Racquetball Way            Lowell Observatory
               Indianapolis, IN 46260 U.S.A.     1400 West Mare Hill Road
                                                 Flagstaff, AZ 86001 U.S.A.



References:

AAVSO: 1942 "c" scale chart, 2310+40 TY And, Amer. Assoc. Var. Star Obs.,
       Cambridge, Massachusetts, U.S.A.
AGK3: 1975, Dreiter Katalog der Astronomischen Gesellschaft,
      Hamburg-Bergedorf.
Espin, T.E.: 1895, Astron. Nach. 137, 369. [BIBCODE 1895AN....137..369E ]
Kazarovets, E.V., and Samus, N. N.: 1990, Inform. Bull. Var. Stars No. 3530.
Kholopov, P.N., editor, et al.: 1982, New Catalogue of Suspected Variable
      Stars, Moscow.
Kholopov, P.N., editor, et al.: 1985, General Catalogue of Variable Stars,
      Vol. 1, Moscow.
Kholopov, P.N., Samus, N.N., Kazarovets, E.V., Perova, N.B.: 1985, 
      Inform. Bull. Var. Stars No.  2681.
Kholopov, P.N., Samus, N.N., Kazarovets, E.V., and Kireeva, N.N.: 1987,
      Inform. Bull. Var. Stars No. 3058.
Kholopov, P.N., Samus, N.N., Kazarovets, E.V., Frolov, M.S., and Kireeva, N.N.:
      1989, Inform. Bull. Var. Stars No. 3323.