COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                         Number 969

                                      Konkoly Observatory
                                      Budapest
                                      1975 March 5


          upsilon^1 PUPPIS, A PULSATING B3 Ve STAR

The variability of this star (HD57150, alpha_1975 = 7h17m25s delta_1975=
=-36deg41', m_V = 4.78, S = B3 Ve) which shows strong H emission was
discovered by the author in 1970 at the ESO Observatory, where he
made discrete photometric observations with the 6" Zeiss telescope
on several early B-type stars, in a search for new beta CMa variables. 
In the publication (1) where the discovery was announced,
the following statement was made. "It is possible that the 
successive cycles have a different amplitude and shape with a mean
duration of the order of 6.5 hours, but this is hardly more than
a guess".
Photometric observations with the 60" Boyden reflector, which were
started in January and are still being continued, confirm the 
presumption of the changing amplitude, but prove that the period must
be doubled. They show that the star is indeed a pulsating variable
with a period that changes between 12h and 13h. It seems difficult
to attribute these changes of the period entirely to those phase
shifts which result from the interference of two oscillations. The
minimum amplitude observed up to now (6th February) is 0m.025 in V,
the longest observed change in brightness is 0m.06 but the maximum
amplitude may be higher. The amplitude in v is 1.3 - 1.4 times the
amplitude in V. Certain cycles seem to present singularities.
The beat period could not be determined yet because of breaks in
the observations, due to bad weather.
With its unusual long period and its low luminosity the star 
violates the P-L relation known to hold for the "classical" beta CMa
stars


                                     A. van HOOF,

                                     Astronomisch Instituut K.U.L.
                                     Naamsestraat 61,
                                     Leuven, Belgium.


(1) Mededelingen v.d. Kon.Acad. v. Wetenschappen, Letteren en
    Schone Kunsten v. Belgie, XXXV, Nr. 4, 1973



                     NOTE ON upsilon^2 PUPPIS

The variability of upsilon^2 Puppis (HD57219, alpha_1975 = 7h17m45s, delta_1975 =
= -36deg42'. m_V = 5.10, S = B3V) has been announced in I.B.V.S.
No. 807 where the star was described as a beta CMa star with a period
of ~3 hours, (amplitude of the light oscillations 0m.02V), it being
also the brighter component of a spectroscopic binary with a period 
close to twenty-four hours. Those were the conclusions from a
photometric observation campaign made with the 6" Zeiss reflector
of the ESO Observatory at La Silla.
Observations now going on at the Boyden Observatory confirm the
existence of the 3h-oscillations, though their amplitude is smaller 
than it was seen in Chile (presently 0m.02 in v and a bit less
in V). But the 5-6 hour runs on the star show moreover each night
a gradual decrease of the star's brightness by 0m.02 in v and almost
nothing in V. This is interpreted as the reflection effect in a
close binary. The difference in longitude between Bloemfontein and
La Silla (6 1/2 h) and the orbital period (= 24h) make it plausible
now to see in the sudden rise in brightness of the star observed
night after night at the same hour in La Silla, the end of an 
eclipse.


                                         A. van HOOF

                                         Astronomisch Instituut K.U.L.
                                         Naamsestraat 61,
                                         Leuven,
                                         Belgium.