COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                              Number 2945

                                                        Konkoly Observatory
                                                        Budapest
                                                        15 October 1986

                                                        HU ISSN 0374 - 0676


       THE LUMINOSITY OF THE ECLIPSING BINARY HV12714 AND ITS
                        MEMBERSHIP IN THE LMC

The 13th magnitude eclipsing system HV12714 has been previously
studied by Gaposhkin (1972). In Table 10 of his study the system was
assigned an absolute photographic magnitude of -5.0 which puts it at the
same distance as the LMC, and suggests membership in that system. It is
important to confirm these results since they imply that HV12714 is one of
the most luminous eclipsing systems known, and further detailed
investigation would be warranted. In what follows the intrinsic brightness
of HV12714 is investigated using spectral classification.
   If HV12714 is indeed a member of the LMC, and hence intrinsically
luminous, then both the 1.4 day period and the lack of interaction effects
in the light curve preclude a system with significantly evolved components.
The absolute V magnitude calibration of Humphreys and McElroy (1984) for
luminosity class V then indicates that the primary would be an O star. On
the other hand, if HV12714 were a Galactic foreground system it would be
substantially closer than the LMC so its intrinsic luminosity would be
correspondingly lower. Therefore, unless the primary was a subdwarf, its
spectral type would be later than O or early B despite the fact that the
evolutionary status of the components could not be accurately deduced from
the light curve in this case.
   A classification spectrum of HV12714 was obtained on Dec. 19,1985
with the '2-D Frutti' detector on the 1.0 metre telescope at CTIO. The
spectrum shows strong Balmer lines and prominent Ca K absorption. A large
Balmer discontinuity is also seen. Comparison with standards observed on
the night of observation along with those of Jacoby et al. (1984) indicate
that the spectrum of HV12714 is that of an early A dwarf. The absolute B
magnitude of such a star would be approximately +1.0 (Allen 1973).
Therefore the luminosity given by Gaposhkin (1972) appears to be in error
and the system seems not to be a member of the LMC.
   The author wishes to acknowledge gratefully S. Heathcote's assistance
with the observations and prereduction of the data frames.


                        T.J. DAVIDGE (*)

                      Physics Department
                    University of Victoria
                    Victoria, B.C., V8W 2Y2
                            CANADA



References:

Allen, C.W., 1973, 'Astrophysical Quantities', 3rd Edition, Athlone Press. [BIBCODE 1973asqu.book.....A ]
Gaposhkin, S., 1972, SAO Special Report No. 310.
Humphreys, R.M., McElroy, D.B., 1984, Ap. J., 284, 565. [BIBCODE 1984ApJ...284..565H ]
Jacoby, G.H., Hunter, D.A., Christian, C.A., 1984, Ap. J. Supp., 56, 257. [BIBCODE 1984ApJS...56..257J ]


(*) Visiting Astronomer, Cerro-Tololo Inter-American Observatory, operated
    by NOAO for the National Science Foundation