FEROS is a new fiber-fed bench-mounted prism-crossdispersed echelle spectrograph which has been recently cornmissioned at the ESO 1.52-rn telescope at La Silla. The opto-rnechanical concept and performance predictions have been presented by Kaufer & Pasquini.1 In this contribution we present the test results as obtained during two commissioning runs in October and December 1998. Special emphasis is given to the measured performances in efficiency, spectral resolution, straylight contamination, and spectral stability. The definite highlight of the FEROS instrument performance is the high peak detection quantum efficiency of 17% at 550nm (1%©360nm, 16%©440nm, 11%©790nm, 6%@9OOnm). These measured numbers include the 2-mirror telescope, the fiber link, the instrument, and the detector while the whole wavelength range is covered by a single exposure on a thinned EEV 2kx4k 15 micron pixel CCD and a constant resolving power of R = 48.000. In addition the FEROS instrument proved its high spectral stability by radial-velocity observations as carried out on the known radial-velocity standard star 7 Ceti over a time base of 2 months. By recording a calibration-lamp spectrum in parallel with the object spectrum and by the use of a simple cross-correlation technique, a rms of 21 rn/s has been obtained for a data set of 130 individual measurements. FEROS has been made available to the ESO community in January 1999.

Abstract. We present the results of an intensive monitoring program of the jet absorptions in the symbiotic system MWC 560, obtained with the FEROS echelle spectrograph at the ESO 1.5 m Telescope. MWC 560 is a unique jet source because the line of sight lies practically parallel to the jet axis so that the outflowing gas is seen as absorption in the continuum of the accreting object, in the emission line spectrum of the accretion disk and temporary also in the spectrum of the red giant companion. Highly variable, blue-shifted jet absorption components, due to H i, He i, Na i, Ca ii and Fe ii are observed, which are detached from the undisplaced, narrow emission line components. The allowed emission lines from neutral and singly ionized heavy elements vary simultaneously with the strongly variable continuum emission. Therefore they can be attributed to the irradiated (chromospheric) layers of the neutral part of the accretion disk. The fluxes of forbidden emission lines are practically constant because they originate in a much larger volume. The structure and variability of the jet absorptions indicate the presence of three distinct outflow regions along the jet axis: i. An initial acceleration region above the disk with low velocities <600 km s −1 which covers only partly the central continuum source; ii. A highly variable outflow region covering the continuum source and up to about half of the line emission from the disk. This region shows repeatedly high velocity components ≈1800−2500 km s −1 which are decelerated to <1500 km s −1 within one to a few days. The appearance of high velocity components is anti-correlated and therefore closely related to the low velocity absorptions of region i. The life time of the high velocity components suggests that region ii extends to about one to a few AU from the jet source; iii. A steady flow at an intermediate velocity of ≈900−1300 km s −1 at a distance of the order ∼10 AU from the jet source. This component covers the hot continuum source and the entire narrow line region of the accretion disk. At the beginning of our campaign region iii covers also the extended red giant companion with two absorption components at 1250 km s −1 and 1140 km s −1 , which can be considered as terminal velocities v∞ of the jet outflow. The components disappear during the following several weeks as expected for the end of an occultation phase of the red giant by the collimated jet occuring probably regularly once per binary orbit. Several fast moving (1300−1700 km s −1 ), narrow absorptions are present in the Ca ii resonance lines. The high speed, low column density, and the long life time (∼months) suggest that these are radiative bow shocks in the jet cocoon generated by the collision of the transient high velocity components with slower moving jet material. A geometric model for the jet outflow in MWC 560 is presented. System parameters are derived based on our spectroscopic data and previous studies. Beside other parameters a binary separation of the order 4 AU, a jet inclination of <16•...

Abstract. We Maps of the distribution of the spotted regions on the photosphere of the binary components were derived using the Maximum Entropy and Tikhonov photometric regularization criteria. Rotational modulation was observed in Hα and He  D 3 in anti-correlation with the photometric light curves. Both flares occurred at the same binary phase (0.85), suggesting that these events took place in the same active region. Simultaneous X-ray observations, performed by ASM on board RXTE, show several flare-like events, some of which correlate well with the observed optical flares. Rotational modulation in the X-ray light curve has been detected with minimum flux when the less active G5 V star was in front. A possible periodicity in the X-ray flare-like events was also found.

Abstract. ω Ori (HD 37490, HR 1934) is a Be star known to have presented variations. In order to investigate the nature and origin of its short-term and mid-term variability, a study is performed of several spectral lines (Hα, Hδ, He i 4471, 4713, 4921, 5876, 6678, C ii 4267, 6578, 6583

Abstract. The eclipsing P Cygni-type star R 81 (HDE 269128, HIP 24080) of spectral type B2.5 Ia-0 in the Large Magellanic Cloud was studied on the basis of a long continuous time series with simultaneous high-resolution Feros spectra and photometric measurements in the Strömgren system. The stellar parameters derived for the primary are T eff = 19 500 K and R = 96 R . The orbital period of the binary is 74.566 days. The mean light curve shows two eclipses, a brightness maximum just after the eclipse of the hypergiant and a slow decline of brightness between the two minima. For the first time, the orbital motion of the primary has been detected. The system is close and eccentric (e = 0.569) and both components nearly fill their Roche volumes. A spectral signature of the companion of the hypergiant has not been found. We suspect that the secondary is embedded in a shell or disk of material accreted from the primary. In addition, line profile variations with a period of about 11 days, probably caused by non-radial pulsation, were observed. The line profiles indicate a strong wind from the primary with an outflow velocity of about 150 km s −1 . Near primary eclipse, strong absorptions in low excitation lines emerge abruptly that point to an outflow of enhanced density and higher velocity in the direction towards and beyond the secondary.