We present astrometric analysis of archival data of water masers in the star-forming region Sharpless 269 ( S269 ) IRS 2w , observed with the VLBI Exploration of Radio Astrometry .
An annual parallax of one of the bright maser features in this region was previously reported to be 0.189 \pm 0.008 milliarcsecond ( mas ) using part of the same archival data as we used .
However , we found that this maser feature is not the best to represent the annual parallax to S269 IRS 2w because the morphology is remarkably elongated in the east–west direction .
For this study we have selected another maser feature showing simpler morphology .
This makes the new annual parallax estimate more credible .
Our newly obtained annual parallax is 0.247 \pm 0.034 mas , corresponding to 4.05 ^ { +0.65 } _ { -0.49 } kpc .
This value is well consistent with the 3.7–3.8 kpc obtained using the kinematic distance estimates and photometric distance modulus .
We considered two hypotheses for the water maser spatial distribution , a bipolar outflow and an expanding ring , in a kinematic model fitting analysis with a radially expanding flow .
At this stage , any conclusions about the systemic proper motion could not be drawn from the kinematic analysis .
Alternatively , we evaluated the mean proper motion to be ( 0.39 \pm 0.92 , -1.27 \pm 0.90 ) mas yr ^ { -1 } eastward and northward , respectively , from the obtained proper motions of the detected water maser features .
The newly obtained annual parallax and mean proper motion give the peculiar motion of S269 IRS 2w to be ( U _ { \mathrm { s } } , V _ { \mathrm { s } } , W _ { \mathrm { s } } ) of ( 8 \pm 6 , -21 \pm 17 , 1 \pm 18 ) km s ^ { -1 } .