COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                        Number 3026


                                              Konkoly Observatory
                                              Budapest
                                              25 May 1987

                                              HU ISSN 0374-0676


              A NEW LONG-PERIOD CEPHEID IN THE LMC *

   During a photometric investigation of the metal content of 47 FG
supergiants in the LMC, several objects turned out to be variable (van
Genderen, van Driel and Greidanus, 1986). One of them was situated in the
Cepheid instability strip i.e. HDE 270100. The identification chart is given
by Fehrenbach and Duflot (1974, catalogue number is G 458, chart 598).
According to Fehrenbach and Duflot (1982) the coordinates for 1950 are
alpha= 5h44.97m and delta= -67d30'.6, the spectral type is G2:Ia, V_J = 11.84 (the
subscript J refers to the UBV system).


                            [FIGURE 1]

 Fig. 1. The light- and colour curves of the recently discovered long-period
 Cepheid in the LMC HDE 270100 = G 458, relative to the comparison star 
 in log intensity scale.


* Observations collected at the ESO, La Silla, Chile

  In order to establish the precise nature or its variability, a
photometric program was started in September 1986. The observations were made
with the 90-cm Dutch telescope at the ESO, La Silla, Chile, equipped with the
simultaneous VBLUW photometer of Walraven. The star was measured twice per
night alternated by the comparison star HD 33486 (B9, 8.1m). The diaphragm
aperture was 16". Integration times were of the order of 2 minutes per
measurement. We present here a short report on the results of the months
September 1986 to January 1987. Figure 1 shows the observations relative to
the comparison star for V, V-B and B-L in log intensity scale as a function of
Julian Date). A more complete discussion with more observations will be given
later. The preliminary period P - 75d. The light- and colour curves are
characteristic of long period Cepheid of population I in the Magellanic Clouds
(van Genderen 1983a and references therein).
   The median values for the V and B-V of the UBV system transformed from V
and V-B of VBLUW system amount to V_J = 11.8, (B-V)J = 0.95. The visual light
amplitude is 0.45m. According to its position in the V-B/B-L diagram the
interstellar reddening is small (van Genderen, van Driel and Greidanus 1986).
   The new Cepheid has a period close to that of the LMC Cepheid HV 2827 of
which P = 78.86d, V_J = 12.3 and the visual light amplitude 0.6m (van 
Genderen 1983a, b).


                          A.M. VAN GENDEREN 1
                          TH. AUGUSTEIJN 2
                          J.J. PREIN 1
                          E.C. ENGELSMAN 1
                          E. VAN DER GRIFT 1


1) Leiden Observatory, Huygens Laboratory, Postbus 9513, 2300 RA Leiden, The
   Netherlands
2) Astronomical Institute "Anton Pannekoek", Roetersstraat 15, 1018 WB
   Amsterdam, The Netherlands


References :

Fehrenbach, Ch., Duflot, M.: 1974, Astron. Astrophys. Suppl. 16, 365 [BIBCODE 1974A&AS...16..365F ]
Fehrenbach, Ch., Duflot, M.: 1982, Astron. Astrophys. Suppl. 48, 409 [BIBCODE 1982A&AS...48..409F ]
van Genderen, A.M.: 1983a, Astron. Astrophys. Suppl. 52, 423 [BIBCODE 1983A&AS...52..423V ]
van Genderen, A.M.: 1983b, Astron. Astrophys. 124, 223 [BIBCODE 1983A&A...124..223V ]
van Genderen, A.M., van Driel, W., Greidanus, H.: 1986, Astron. Astrophys.
   155, 72 [BIBCODE 1986A&A...155...72V ]