http://arxiv.org/abs/2006.01344
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.
H. Yang, S. Cho, Y. Yun, et. al.
Wed, 3 Jun 20
46/83
Comments: 7 pages, 4 figures, 1 table, Published in MNRAS