COMMISSION 27 OF THE I.A.U.
               INFORMATION BULLETIN ON VARIABLE STARS
                            Number 1450

                                                      Konkoly Observatory
                                                      Budapest
                                                      1978 July 28


   HR 4511 - A POSSIBLE VERY LONG-PERIOD CLASSICAL CEPHEID
              IN THE CLUSTER STOCK 14

It has been stated in the literature that HR 4511 (=HD 101947)
shows slight variations in the optical lightcurve (e.g. Fernie,
1977) and in some spectral lines, especially Ha (e.g. Bidelman
et al., 1963).
   We have carried out an extensive program at the European Southern
Observatory at La Silla, Chile, obtaining photometry, spectrum
scans, polarization measurements and coude-spectra, partly through
the kind cooperation of several colleagues.
   From our reductions the following can be stated now:

- HR 4511 shows a lightcurve similar to the one presented by
  van Genderen and The (1978) for Tr 27-102
- The period is estimated to be of the order of 125 days
- We find amplitudes of 0m.17 in u, 0m.24 in v, 0m.16 in b, and
  0m.13 in y, but they may be slightly larger
- The spectral type is G0 Ia
- Most of the Halpha-profiles we obtained show central emission
- It is a member of the loose open cluster Stock 14 (Moffat and
  Vogt, 1975)

   Our results are consistent with the concept of an extremely long-
period low amplitude classical cepheid. These cepheids are very
difficult to find and until today no cepheid of such a long period
is known in our Galaxy. Also because of its cluster membership.
HR 4511 may be of great importance in cepheid research. It would
therefore be of great value if observers in the southern hemisphere 
could continue the study of this star. Our full results
have been submitted to Astronomy and Astrophysics, but are in
the meantime available on request.


    W. EICHENDORF                       BO REIPURTH

    Astronomisches Institut             Copenhagen University
    Postfach 102148                     Observatory
    D-9630 Bochum 1                     Oster Voldgade 3
    Fed. Rep. of Germany                DK-1350 Copenhagen K
                                        Denmark



References:

Bidelman, W.P. et al.: 1963, Publ. Astron. Soc. Pacific 75, 524 [BIBCODE 1963PASP...75..524B ]
Fernie, J.D.: 1977, I.B.V.S. No. 1305
Moffat,. A.F.J., Vogt, N.: 1975, Astron. Astrophys. Suppl. 20, 125 [BIBCODE 1975A&AS...20..125M ]
van Genderen, A.M., The, P.S.: 1978, Astron. Astrophys. 64 L1 [BIBCODE 1978A&A....64L...1V ]