出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We report on the parallax measurement of S269 H2O maser with VERA (VLBI Exploration of
Radio Astrometry). We have monitored the positions of S269 H2O masers for 1 year with VERA,
and successfully measured its parallax to be 189±8 micro-arcsec. This corresponds to the source
distance of 5.28+0.24
−0.22 kpc, and is the smallest parallax (and thus the largest distance) ever measured
by means of trigonometric parallax. We also discuss the constraints on the Galactic rotation speed
obtained from the proper motion of S269.
