COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 3046

                                        Konkoly Observatory
                                        Budapest
                                        13 July 1987

                                        HU ISSN 0374-0676


           UBV PHOTOMETRY OF NOVA ANDROMEDAE 1986

  Nova And 1986 (R.A. = 23h09m47.72s; D. = +47d12'00.8" (1950); l = 110d;
b = -13d) was discovered by Mitsury Suzuki on Dec. 5.44 (Kosai, 1986). We
report here our systematic UBV photoelectric observations between December
11.73 (1986) and January 21.75 (1987), when the star declined from V = 7.28
to V = 11.32. Between January and February 1987 we followed photographically
the fading of the Nova toward V = 12.4.
  All the observations were performed with the 0.4m reflector of the "G.
Colombo" Observatory. Photoelectric measurements were carried out at the
Cassegrain focus (F/20) equipped with a RCA 931 B photomultiplier tube and
UBV filters. The comparison star was 7 And (V = 4.52; B-V = 0.31; U-B = 0.02,
from USNO Photoelectric Catalogue). Photovisual magnitudes were estimated on
Kodak Tri-X plates exposed through a filter Schott GG 495 (2mm) at the Newton
focus (F/5) of the same reflector, adopting the comparison star sequence from
AAVSO Chart No. 230746.
   The V light curve is presented in Figure 1, where our data are plotted
as black dots. As open dots the V estimates published in IAU Circulars 4281,
4282, 4293, 4342, 4360 are also reported. The light curve shows that the Nova
attained the maximum at V=6.3 on Dec. 7, 1986. After that the Nova declined
rapidly (t2 = 10d; t3 = 21d) with a rate of 0.20 mag/day. The star entered
in the transition phase on December 31 and the final decline started about
on January 20.
   The (U-B) colour index showed a regular increase from -0.69 (S.D. 0.02)
to -0.53 (S.D. 0.04) between Dec. 22 and Jan. 21. By contrast the (B-V) colour
index displayed formerly a decline from +0.41 (S.D. 0.02) to +0.18 (S.D. 0.02)
about at the end of December, followed by an increase up to +0.52 (S.D. 0.04)
in January. These facts can be accounted for by the appearance of strong


                               [FIGURE 1]


emission bands in the spectrum of the star (L. Rosino, personal communication),
following the usual behaviour of Novae in this evolutionary phase.





                        GIANNANTONIO MILANI
                        ANDREA TONELLO
                        GIANCARLO FAVERO

                        "G. Colombo" Observatory
                        Padova - Italy


Reference:
Kosai, M., 1986, IAU Circular 4281 [BIBCODE 1986IAUC.4281....2K ]