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

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

Acta Astronomica

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2019

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Vol. 69, No. 1

25--44

EN

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.

2

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

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

Acta Astronomica

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2017

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Vol. 67, No. 3

225--242

EN

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.

3

An X-Shooter View of the Symbiotic Star [JD2002] 11

Hajduk M., Gromadzki M., Mikołajewska J., Miszalski B., Soszyński I.

Acta Astronomica

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2015

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Vol. 65, No. 2

139--149

EN

We aimed to verify the nature and derive the basic parameters of the symbiotic star candidate [JD2002] 11. For this purpose, we obtained and analyzed an X-Shooter spectrum of [JD2002] 11. We also used optical and infrared photometry available for the object. Emission-line diagnostic ratios are characteristic of a dusty type symbiotic star and reveal a two-component nebula (low- and high-density). The spectral energy distribution is well fitted with a two-component black body spectrum with the respective temperatures of 1150 K and 600 K. The total luminosity of 3000 L⊙ is consistent with the expected luminosity of a typical Mira star, embedded in an optically thick dust shell. We conclude that [JD2002] 11 is the ninth symbiotic star in total and only the second dusty type symbiotic star discovered in the Small Magellanic Cloud.

4

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

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

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2012

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Vol. 62, No. 2

133--151

EN

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.

5

Light Curves of Symbiotic Stars in Massive Photometric Surveys I: D-Type Systems

Gromadzki M., Mikołajewska J., Whitelock P., Marang F.

Acta Astronomica

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2009

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Vol. 59, No. 2

169--191

EN

ASAS, MACHO, OGLE and SAAO JHKL light curves of 13 stars, that have at some time been classified as D-type symbiotic stars, are analyzed. Most of the near-IR light curves that have been monitored over many years show long-term changes due to variable dust obscuration, in addition to the stellar pulsation. The distances to these objects are derived from the period-luminosity relation and estimates of the mass-loss rates made from the K0-[12] color. We reclassify AS 245 as an S-type symbiotic star with a semi-regular cool component and a pulsation period of about one year. The periods of the large amplitude pulsations of SS73 38 (463 days), AS 210 (423 days) and H2-38 (395 days) are estimated for the first time, confirming that they are symbiotic Miras. A comparison of the symbiotic Miras with normal Miras of similar pulsation period shows that the symbiotic stars have on average higher values of K0-[12]. This may indicate that they have higher mass-loss rates, or more likely that the dust which is being lost by the Mira is trapped within the binary system.

6

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

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

Acta Astronomica

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2006

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Vol. 56, No. 1

97--125

EN

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.