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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.

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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.

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Light Curves of Symbiotic Stars in Massive Photometric Surveys II. S and D'-Type Systems

Gromadzki M., Mikołajewska J., Soszyński I.

Acta Astronomica

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2013

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Vol. 63, No. 4

405--428

EN

We present results of period analysis of ASAS, MACHO and OGLE light curves of 79 symbiotic stars classified as S and D'-type. The light curves of 58 objects show variations with the orbital period. In case of 34 objects, orbital periods are estimated for the first time, which increases the number of symbiotic stars with known orbital periods by about 64%. The light curves of 46 objects show, in addition to the long-term or/and orbital variations, short-term variations with time scales of 50-200 days most likely due to stellar pulsations of the cool giant component. We also report eclipse-like minima and outbursts present in many of the light curves.

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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.