Asymmetric distributions of H2O and SiO masers towards V627 Cas

Abstract

We performed simultaneous observations of the H2O 6(1,6) - 5(2,3) (22.235080 GHz) and SiO v= 1, 2, J = 1 - 0, SiO v = 1, J = 2 - 1, 3 - 2 (43.122080, 42.820587, 86.243442, and 129.363359 GHz) masers towards the suspected D-type symbiotic star, V627 Cas, using the Korean VLBI Network. Here, we present astrometrically registered maps of the H2O and SiO v = 1, 2, J = 1 - 0, SiO v = 1, J = 2 - 1 masers for five epochs from January 2016 to June 2018. Distributions of the SiO maser spots do not show clear ring-like structures, and those of the H2O maser are biased towards the north-north-west to west with respect to the SiO maser features according to observational epochs. These asymmetric distributions of H2O and SiO masers are discussed based on two scenarios of a bipolar outflow and the presence of the hot companion, a white dwarf, in V627 Cas. We carried out ring fitting of SiO v = 1, and v = 2 masers and estimated the expected position of the cool red giant. The ring radii of the SiO v = 1 maser are slightly larger than those of the SiO v = 2 maser, as previously known. Our assumption for the physical size of the SiO maser ring of V627 Cas to be the typical size of a SiO maser ring radius (\sim4 au) of red giants yields the distance of V627 Cas to be \sim1 kpc.

arXiv comment7 pages, 4 figures, 1 table, Published in MNRAS

References in corpus (16)

• Gaia Data Release 2. Summary of the contents and survey properties
• A catalogue of symbiotic stars
• PTF11kx: A Type-Ia Supernova with a Symbiotic Nova Progenitor
• The Mira variable S Ori: Relationships between the photosphere, molecular layer, dust shell, and SiO maser shell at 4 epochs
• High Precision Astrometric Millimeter VLBI Using a New Method for Atmospheric Calibration
• NLTE Model Atmosphere Analysis of the LMC Supersoft X-ray Source CAL 83
• High resolution observations of SiO masers: comparing the spatial distribution at 43 and 86 GHz
• Sub-au imaging of water vapour clouds around four Asymptotic Giant Branch stars
• Comparison of Gaia DR2 Parallaxes of Stars with VLBI Astrometry
• Accurate Parallax Measurement toward the Symbiotic Star R Aquarii
• Mapping the circumstellar SiO maser emission in R Leo
• Astrometrically Registered Simultaneous Observations of the 22 GHz H${}_2$O and the 43GHz SiO masers towards R Leonis Minoris using KVN and Source/Frequency Phase Referencing
• Astrometrically registered maps of H2O and SiO masers toward VX Sagittarii
• A long-term VLBA monitoring campaign of the v=1, J=1-0 SiO masers toward TX Cam - I. Morphology and Shock Waves
• The 43GHz SiO maser in the circumstellar envelope of the AGB star R Cassiopeiae
• Simultaneous VLBI Astrometry of H2O and SiO Masers toward the Semiregular Variable R Crateris

Cited by in corpus (2)

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