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St 2-22 - Another Symbiotic Star with High-Velocity Bipolar Jets

100%

Tomov T. , Zamanov R. , Gałan C. , Pietrukowicz P.

2017

tom Vol. 67, No. 3

225--242

We report the detection of high-velocity components in the wings of Hα emission line in spectra of symbiotic binary star St 2-22 obtained in 2005. This finding encouraged us to start the present investigation in order to show that this poorly-studied object is a jet-producing system. We have used high-resolution optical and low-resolution near-infrared spectra, as well as available optical and infrared photometry, to evaluate some physical parameters of the St 2-22 components and characteristics of the jets. We confirm that St 2-22 is a S-type symbiotic star. Our results demonstrate that an unnoticed outburst, similar to those in classical symbiotic systems, occurred in the first half of 2005. During the outburst, collimated bipolar jets were ejected by the hot component of St 2-22 with an average velocity of about 1700 km/s.

Hen 3-160 - the First Symbiotic Binary with Mira Variable S Star

88%

Gałan C. , Mikołajewska J. , Monard B. , Iłkiewicz K. , Pieńkowski D. , Gromadzki M.

tom Vol. 69, No. 1

25--44

Hen 3-160 is reported in Belczyński et al. catalog as a symbiotic binary system with M7 giant donor. Using V- and I-band photometry collected over 20 years we have found that the giant is a Mira variable pulsating with 242.5-day period. The period-luminosity relation locates Hen 3-160 at the distance of about 9.4 kpc, and its Galactic coordinates (l=267.°7, b=-7.°9) place it ≈1.3 kpc above the disk. This position combined with relatively high proper motions (μαcosδ=-1.5 mas/yr, μ_δ=+2.9 mas/yr, Gaia DR2) indicates that Hen 3-160 has to be a Galactic extended thick-disk object. Our red optical and infrared spectra show the presence of ZrO and YO molecular bands that appear relatively strong compared to the TiO bands. Here we propose that the giant in this system is intrinsic S star, enriched in products of slow neutron capture processes occurring in its interior during an AGB phase which would make Hen 3-160 the first symbiotic system with Mira variable S star.

The Optical Gravitational Lensing Experiment. Optical Counterparts to the X-ray Sources in the Galactic Bulge

75%

Udalski A. , Kowalczyk K. , Soszyński I. , Poleski R. , Szymański M. K. , Kubiak M. , Pietrzyński G. , Kozłowski S. , Pietrukowicz P. , Ulaczyk K. , Skowron J. , Wyrzykowski Ł.

Acta Astronomica

2012

tom Vol. 62, No. 2

133--151

We present a sample of 209 variable objects - very likely optical counterparts to the X-ray sources detected in the direction of the Galactic center by the Galactic Bulge Survey (GBS) carried out with the Chandra satellite. The variable sources were found in the databases of the OGLE long term survey monitoring regularly the Galactic bulge since 1992. The counterpart candidates were searched based on the X-ray source position in the radius of 3.9 arcsec. Optical light curves of the candidates comprise a full variety of variability types: spotted stars, pulsating red giants (potentially secondary stars of symbiotic variables), cataclysmic variables, eclipsing binary systems, irregular non-periodic objects including an AGN (GRS 1734-292). Additionally, we find that positions of 19 non-variable stars brighter than 16.5 mag in the OGLE databases are so well aligned with the X-ray positions (<0.75 arcsec) that these objects are also likely optical counterparts to the GBS X-ray sources. We provide the OGLE astrometric and photometric information for all selected objects and their preliminary classifications. Photometry of the candidates is available from the OGLE Internet archive.

Searching for Flickering Variability in Several Symbiotic Stars and Related Objects: BX Mon, V471 Per, RS Oph, V627 Cas, CI Cam, V886 Her, Z And, T CrB, MWC 560, V407 Cyg

51%

Gromadzki M. , Mikołajewski M. , Tomov T. , Bellas-Velidis I. , Dapergolas A. , Gałan C.

Acta Astronomica

2006

tom Vol. 56, No. 1

97--125

UBVRI photometric observations of 10 symbiotic stars and related objects obtained in the period 2002-2003 are presented. Analyzing differential light curves we found rapid light variations with timescales of tens of minutes and significant amplitudes in the well-known flickers MWC 560, RS Oph, V407 Cyg and T CrB. MWC 560 and V407 Cyg demonstrate quasi periodic oscillations (QPO) with similar amplitudes and timescales. Flickering and unusual flare in V627 Cas as well as some indications of flickering presence in BX Mon are detected. The existence of 29 min oscillations in Z And with an amplitude ≈0.02 mag in the U-band is confirmed. Only one symbiotic star, V471 Per, and both non symbiotic, CI Cam and V886 Her, seem to be constant on flickering timescales. Nevertheless, small night to night changes in the brightness of V886 Her were observed as well.