COMMISSION 27 OF THE I. A. U.
	INFORMATION BULLETIN ON VARIABLE STARS
		    Number 2642

			          Konkoly Observatory
			          Budapest
			          11 December 1984

			          HU ISSN 0374 - 0676




     HD 208496 (HR8369) : A DOUBLE - LINED ECLIPSING BINARY


   In a recent IBVS, Manfroid and Mathys (1984) presented a
partial light curve of HD 208496 (HR8369, m_v=6.12, Sp =F3V),
which the fourth edition of the Bright Star Catalogue (Hoffleit,
1982) mentions as a possible eclipsing binary. Manfroid  and
Mathys confirmed the eclipsing nature of the star and established
an orbital period of 1.464047 +- 0.000011 days.

   HR8369 was included in our radial velocity survey at ESO,
La Silla, of previously unobserved starts in the Bright Star 
Catalogue. Two spectrograms were obtained in June 1983. with the
ESO 1.5m telescope and coude spectrograph (20 A/mm). The plates
immediately showed spectral lines of two components of rather
similar spectral types, the lines of one component (the 
primary) being noticeably stronger and broader those of the
secondary. We estimate the rotational velocities to be rather
large, 70 and 50 km/s, which explains why initial attempt to
observe the star with the CORAVEL scanner were unsuccessful.
   Radial velocity measurements of the two plates indicate a
mass ratio of about 0.85 +- 0.05 and a systemic velocity around
40 km/s. Since Manfroid and Mathys gave non zero-point for their
ephemeris, we cannot calculate the precise of our observations. 
If, however, we assume that the largest velocities
measured approximate the maximum values, we derive masses of
approx. 1.4 and 1.2 M_sun. The observed rotations correspond to
radii of the order of 2.0 and 1.5 R_sun.
   These figures are consistent with expectations for F3V
stars, depending on the age of the system. However, being
based on only two plates, they are obviously not by themselves
of sufficient precision to add significantly to our knowledge
of the absolute dimensions of early F stars. The purpose of this
note is to point out that HR8369 is a bright system of favourable
period which may yield good data if light and radial velocity
curves are carefully determined, and to encourage such 
observations. Our own individual radial velocity measurements will
appear in a catalogue to be published soon (Nordstrom and
Andersen, 1984).





		      J. ANDERSEN
		      K.S. JENSEN
		      B. NORDSTROM
		      Copenhagen University Observatory
		      Brorfeldevej 23
		      DK-4340 Tollose
		      Denmark.


References:

Hoffleit, D. 1982, The Bright Star Catalogue, Yale Univ.Obs.
Manfroid, J., Mathys, D. 1984, IAU Inf. Bull. Var. Stars, No. 2616.
Nordstrom, B., Andersen, J.: 1984, Astron. Astrophys. Suppl. to
   be submitted [BIBCODE 1985A&AS...61...53N ]