COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                   Number 3019



                                Konkoly Observatory
                                Budapest
                                4 May 1987

                                HU ISSN 0374-0676

     EARLY UBV PHOTOMETRY OF SUPERNOVA 1987A IN LMC*

The supernova 1987A in the Large Magellanic Cloud could be
observed by the author just after its detection on Feb. 24
during the nights of Feb. 24/25 and Feb. 25/26, using the
ESO 50cm telescope on La Silla/Chile. Observations were made
in UBV Johnson system using the blue-sensitive photomultiplier
EMI 6256.
Because of a limit of 5.5 mag for V-brightness it was necessary
to mount a mask on the telescope tube which reduced the 
aperture to 25 cm.
Stars in E-regions (Cousins, 1973 - updated by Vogt et al.,
1981) were used as extinction stars; as local comparison stars
served HD 42525 (A0V-type) and HD 43107 (B8V-type).
  As reported by Wampler (1987) and West (1987) the supernova
brightened very rapidly during a few hours by a factor of 200
till about Feb. 23.4 UT and reached around V = 6 mag. One night
later V went up to a value between 5 and 4.5 mag.
Now the first few nights after detection of SN 1987A were 
interesting for the fact that its V-brightness was still 
somewhat increasing before reaching a maximum for the following
days.
The results of my UBV measurements are given in Table I.
The observations started on Feb. 25 at about 1:30 UT with
V = 4.65 mag. Five hours later V had increased slowly, but
rather continuously to V = 4.60 mag. One night later around
V = 4.52 mag was measured during five hours, indicating a more
slowly increase of V than before.
The change of the colours during both nights shows that B
remained about constant and U dropped slightly.
Further observations with the ESO 50cm telescope were carried
out by Magnusson (1987) beginning on Feb. 26/27. The evolution
of the lightcurves during the next few days shows a rather
constant value of V around 4.4 mag and a significant decrease
of B and U, together with an increase of the infrared 
brightness I.
Altogether the evolution of the B-lightcurve indicates a maximum 
of B between Feb. 25 and 26; the maximum of U was reached
probably before Feb. 24. Further photometric observations will
provide us with data about the final maximum of V which is
still some unclear at the moment. As far as we know, this
supernova is too faint for a type II supernova, probably due
to physical conditions of this unusual object itself.

*Observations collected at ESO/La Silla, Chile


              Table I: UBV data

Date UT       V       B-V     U-B
Feb. '87      (mag)   (mag)   (mag)

25.067        4.65    0.03    -0.68
25.077        4.64    0.03    -0.70
25.087        4.63    0.03    -0.69

25.246        4.60    0.08    -0.66
25.254        4.61    0.07    -0.66
25.264        4.60    0.07    -0.62
-----------------------------------
26.226        4.52    0.17    -0.47
26.242        4.52    0.16    -0.46
26.259        4.52    0.17    -0.48
26.270        4.52    0.18    -0.47
26.289        4.51    0.19    -0.47
-----------------------------------
Error (+/-)   0.01    0.01     0.02


Acknowledgements:
I would like to thank L. Kohoutek/Hamburg for a photometry
program and P. Magnusson/Uppsala for his still unpublished
photometric data of SN 1987A.


                                THILO GUNTER
                                Hamburger Sternwarte
                                Gojenbergsweg 112
                                D-2050 Hamburg 80
                                Federal Republic of Germany


References;

Cousins, A.W.J., 1973: Mem. Roy. Astron. Soc. 77, 223 [BIBCODE 1973MmRAS..77..223C ]
Magnusson, P., 1987: private communication
Vogt, N., Geisse, H.S., Rojas, S., 1981: AA Suppl. 46, 7 [BIBCODE 1981A&AS...46....7V ]
Wampler, J., 1987: ESO Messenger 47, 26, in "The Supernova
  in the LMC" [BIBCODE 1987Msngr..47...26W ]
West, R.M., 1987: ESO Messenger 47, 30, in "The Supernova
  in the LMC" [BIBCODE 1987Msngr..47...30W ]