Related papers: Spectral variability of the IR-source IRAS 01005+7…

To search for and study the instabilities in the atmospheres of selected post-AGB stars, we have performed a long-term high-resolution spectroscopy (R=60000) with the spectrograph NES of the 6-meter BTA telescope. Low-amplitude pulsations,…

The observations and comprehensive study of intermediate initial mass stars at the late stages of evolution, and after the asymptotic giant branch (AGB) in particular, are of crucial importance to identify the common properties for the…

We present photoelectric and spectral observations of a hot candidate proto-planetary nebula - early B-type supergiant with emission lines in spectrum - IRAS 19336-0400. The light and color curves display fast irregular brightness…

While the effect of rotation on spectral lines is complicated in rapidly-rotating stars because of the appreciable gravity-darkening effect differing from line to line, it is possible to make use of this line-dependent complexity to…

We have used the RXTE and INTEGRAL satellites simultaneously to observe the High Mass X-ray binary IGR J19140+0951. The spectra obtained in the 3-80 keV range have allowed us to perform a precise spectral analysis of the system along its…

IRC +10420 is one of the few known massive stars in rapid transition from the Red Supergiant phase to the Wolf-Rayet or Luminous Blue Variable phase. The star has an ionised wind and using the Br gamma hydrogen recombination emission we…

A single dish monitoring of millimeter maser lines SiS J=14-13 and HCN nu_2 = 1^f J=3-2 and several other rotational lines is reported for the archetypal carbon star IRC+10216. Relative line strength variations of 5%~30% are found for eight…

We report the first mid-IR detection of highly disturbed ionized gas in the ultraluminous infrared galaxy IRAS F00183-7111. The gas, traced by the 12.81um [NeII] and 15.56um [NeIII] lines, spans a velocity range of-3500 to 3000 km/s with…

We present radial velocities of the M8V-type, very low-mass star vB 10 that have been obtained at four different epochs of observations between 2001 and 2008. We use high-resolution (R ~ 20,000) near-infrared (J-band) spectra taken with the…

We have made a serendipitous discovery of an enigmatic outflow source, IRAS 05506+2414 (hereafter IRAS 05506), as part of a multi-wavelength survey of pre-planetary nebulae (PPNs). The HST optical and near-infrared images show a bright…

Based on high-spectral resolution observations performed with the echelle spectrograph NES of the 6-meter telescope, we have studied the peculiarities of the spectrum and the velocity field in the atmosphere and envelope of the optical…

Based on the high resolution spectral monitoring conducted at the 6-m BTA telescope, we study the optical spectrum of the high-latitude variable V534 Lyr. Heliocentric radial velocities Vr corresponding to the positions of all metal…

Searching for variability, we have observed a sample of hot post-AGB stars and young Planetary Nebulae candidates with the Very Large Array at 4.8, 8.4, and 22.4 GHz. The sources had been previously detected in the radio continuum, which is…

The origin of the near-infrared (NIR) HI emission lines in young stellar objects are not yet understood. To probe it, we present multi-epoch LBT-LUCIFER spectroscopic observations of the Pa{\delta}, Pa{\beta}, and Br{\gamma} lines observed…

Searches for small exoplanets around solar-type stars are limited by stellar physical variability. While chromospheric variability is well studied, observing, modeling. and understanding the much smaller fluctuations in photospheric…

We present the results of a study of spectral features and the velocity field in the atmosphere and the circumstellar envelope of the hypergiant V1302 Aql, the optical counterpart of the IR source IRC+10420, based on high-resolution…

We present an analysis of high-speed spectroscopy of the pulsating subdwarf B star PG 1605+072. Periodic radial motions are detected at frequencies similar to those reported for photometric variations in the star, with amplitudes of up to 6…

While most sources above 10^5Lsun have already formed an Ultracompact HII region (UCHII), this is not necessarily the case for sources of lower luminosity. Characterizing sources in the transition phase, i.e., very luminous objects without…

We present new near-infrared (IR) spectra (0.80-1.35um) of the pre-Main Sequence source PV Cep taken during a monitoring program of eruptive variables we are conducting since some years. Simultaneous photometric and spectroscopic…

We present new narrow-band near-infrared images together with K band spectra of highly collimated bipolar jets close to the IRAS 05487+0255 source. The jets are located at 50" West of the Herbig-Haro 110 outflow. The jets are not visible at…