Asymmetric distributions of H2O and SiO masers towards V627 Cas

Haneul Yang, Se Hyung Cho, Youngjoo Yun, Dong Hwan Yoon, Dong Jin Kim, Hyosun Kim, Sung Chul Yoon, Richard Dodson, María J. Rioja, Hiroshi Imai

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7 Citations (Scopus)


We performed simultaneous observations of the H2O 61,6 - 52,3 (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 (∼4 au) of red giants yields the distance of V627 Cas to be ∼1 kpc.

Original languageEnglish
Pages (from-to)1284-1290
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Publication statusPublished - 2020

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