V 1080 Tauri (BD+24o676) is an emission-line star in the Taurus - Auriga region (Stephenson 1986). This object was originally classified as a pre-main sequence star with a substantial reddening (Walter et al. 1990).
Walter at al. (1990) classified V 1080 Tau as an A3 star according to the spectrum of the blue region which displays absorption lines of the Balmer series. Martín (1993) summarized the respective spectral classifications of V 1080 Tau and found that its spectral type becomes progressively later as one proceeds from the blue to the red spectral region. This suggests the composite spectrum of a hot and a cool star. Spectral lines of the cool component, corresponding to the type G to early K, are indeed present in the H region and their intensities suggest that this star is evolved off the main sequence (Martín 1993). Variations of the radial velocity of the cool star by at least 160 km s were attributed to the orbital motion in the binary. The low Li abundance rules out the pre-main sequence nature of V 1080 Tau.
Bouvier et al. (1993a,b, hereafter B93a and B93b, respectively) discovered the brightness variations on the time scale of 8.8 days with the full amplitude of about 0.3 mag(V). Since the color indices were bluer at minimum brightness, B93a rejected the rotational modulation of a spotted T Tau-type star. Instead, they rose a possibility of the orbital modulation in the binary.
In our paper we present a photometric analysis of the brightness variations in several sets of data, determine the orbital period and show that the modulation can be attributed to the ellipsoidal variations in an Algol-type binary.
© European Southern Observatory (ESO) 2000
Online publication: August 17, 2000