Annual parallax and galactic orbit of Y Librae (IRAS 15090-0549) Mira variable star—GALORB release
Abstract
Using the VLBI Exploration of Radio Astrometry (VERA), we measured the trigonometric parallax of an H2O maser source in a variable star of Mira Cet type, Y Lib, to be 0.855 ± 0.050 mas, corresponding to a distance of 1.17 ± 0.07 kpc. From multi-epoch infrared observations with the Kagoshima University 1 m telescope, we derived the mean J, H, and K'-band magnitudes of Y Lib to be 4.34 ± 0.22 mag, 3.62 ± 0.18 mag, and 3.25 ± 0.16 mag, respectively. The pulsation period of Y Lib was obtained to be 277.2 ± 13.9 d. We derived the effective temperature and radius of Y Lib to be 3100 ± 125 K and 211 ± 11 R_{⊙}, respectively. The peculiar motion of Y Lib Us (motion towards the Galactic center), Vs (motion in the direction of Galactic rotation), and Ws (motion towards the Galactic North Pole) were obtained to be -16 ± 3 km s-1, 25 ± 2 km s-1, and 13 ± 3 km s-1, respectively. After validation, we used the new release of the GALactic ORbit simulation package to trace the past 1 Gyr orbit of Y Lib in the Milky Way. Fitting the orbit of Y Lib with the MWPotential2014 Galactic Potential model produced high eccentricity in the direction perpendicular to the Galactic center, but decreasing the Miyamoto-Nagai disk potential contribution in the Milky Way model produced a reasonable result of the Y Lib orbit.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- October 2019
- DOI:
- 10.1093/pasj/psz075
- Bibcode:
- 2019PASJ...71...92C
- Keywords:
-
- astrometry;
- masers;
- stars: AGB and post-AGB;
- stars: individual (Y Librae)