SIMBAD references

R. Costero, J. Echevarria, M. G. Richer, and A. Poveda, Universidad Nacional Autonoma de Mexico, report their finding that the suspected variable star theta**1 Ori E – the fifth brightest star in the Orion Trapezium, located about 4" north of component A [object 1864 of Parenago 1954, Publ. Sternberg Astr. Inst. 25, 342; also ADS 4186 E, from Aitken's 1932 Double Star Catalogue (Carnegie Inst. of Wash.), 1, 358; listed as NSV 2291 due to Walker, IBVS 1238] – is a double-lined spectroscopic binary. Echelle spectra (resolution about 20000, range 380-680 nm), obtained on Jan. 8-17 with the 2.1-m telescope of the National Observatory at San Pedro Martir, Baja California, show both components to be of spectral type F5. The Li I 670.8-nm line (equivalent width about 0.14 nm) is clearly present in the spectra of both members. The estimated orbital period of the binary is 10.5 ± 1.2 days, and the maximum measured line separation is 154 ± 4 km/s. The spectrum of component E discussed by Herbig (1950, Ap.J. 111, 15) was probably contaminated by the light of component A; the present classification of component E is based on on the comparison of its spectrum with those of several standards of the Morgan and Keenan system, in the interval F0 V-G0 V, taken with the same instrument. These results, the suspected variability (0.4 mag), its being one of the brightest x-ray sources in the Trapezium (Schulz et al. 2003, Ap.J. 595, 365), and the position of the star well above the zero- age main sequence lead us to speculate that this object is an interesting candidate for its being an eclipsing system and/or a flare star. Further observations are encouraged.