We report the results of VLBI observations of H _ { 2 } O masers in the IRAS 20143+3634 star forming region using VERA ( VLBI Exploration of Radio Astronomy ) .
By tracking masers for a period of over two years we measured a trigonometric parallax of \pi = 0.367 \pm 0.037 mas , corresponding to a source distance of D = 2.72 ^ { +0.31 } _ { -0.25 } kpc and placing it in the Local spiral arm .
Our trigonometric distance is just 60 % of the previous estimation based on radial velocity , significantly impacting the astrophysics of the source .
We measured proper motions of − 2.99 \pm 0.16 mas yr ^ { -1 } and − 4.37 \pm 0.43 mas yr ^ { -1 } in R.A. and Decl .
respectively , which were used to estimate the peculiar motion of the source as ( U _ { s } ,V _ { s } ,W _ { s } ) = ( -0.9 \pm 2.9 , -8.5 \pm 1.6 , +8.0 \pm 4.3 ) km s ^ { -1 } for R _ { 0 } = 8 kpc and \Theta _ { 0 } = 221 km s ^ { -1 } , and ( U _ { s } ,V _ { s } ,W _ { s } ) = ( -1.0 \pm 2.9 , -9.3 \pm 1.5 , +8.0 \pm 4.3 ) km s ^ { -1 } for R _ { 0 } = 8.5 kpc and \Theta _ { 0 } = 235 km s ^ { -1 } .
IRAS 20143+3634 was found to be located near the tangent point in the Cygnus direction .
Using our observations we derived the angular velocity of Galactic rotation of the local standard of rest ( LSR ) , \Omega _ { 0 } = 27.3 \pm 1.6 km s ^ { -1 } kpc ^ { -1 } , which is consistent with previous values derived using VLBI astrometry of SFRs at the tangent points and Solar circle .
It is higher than the value recommended by the IAU of \Omega _ { 0 } = 25.9 km s ^ { -1 } kpc ^ { -1 } which was calculated using the Galactocentric distance of the Sun and circular velocity of the LSR .