COMMISSION 27 OF THE I.A.U.
               INFORMATION BULLETIN ON VARIABLE STARS
                            Number 1473

                                                      Konkoly Observatory
                                                      Budapest
                                                      1978 September 18

              R Pup - A VARIABLE AFTER ALL

The G0Ia supergiant R Pup (HD 62058) was first reported by
Gould (1879) to be variable. During the following century however
its variability could not be confirmed by any of the numerous 
subsequent observers. R Pup thus was considered constant since 1907
although recently White (1975) finds some possible evidence for
very slow variations in both brightness and colours.
   R Pup was observed in UBV on 7 nights between January 3 and
January 30, 1977. The comparison stars used were HD 61409 a K0
star and HD 60646 a F0 star. Their, respective magnitudes remained
constant within 0m.002 during this period. R Pup revealed definite
variations in magnitude and colours on a time scale well exceeding 
the 27 days covered by the observations, the V magnitude dropping 
by about 0m.002 a day towards a minimum. The overall amplitude
observed was 0m.19 in U, 0m.12 in B and 0m.06 in V but is certainly
larger.
   The behaviour of R Pup is strikingly similar to that of
HD 101947 for which G0Ia star Reipurth and Eichendorf (1978) 
presume that it may be a very long-period low-amplitude classical
cepheid. Observations of that star and of other hitherto unsuspected 
supergiants will be submitted shortly to Astronomy and
Astrophysics.


                             M.J. STIFT

                             Institut fur Astronomie
                             der Universitat Wien
                             Turkenschanzstr. 17
                             A-1180 Wien, Austria



References:

Gould, B.A.: 1879, Res. Obs. Nac. Argentino Cordoba, 1 [BIBCODE 1879RNAO....1....0G ]
Reipurth, B., Eichendorf, W.: 1978, I.B.V.S. No. 1450
White, S.D.M.: 1975, Astrophys. J. 197, 67 [BIBCODE 1975ApJ...197...67W ]