Abstract / Description of output
We confirm the reality of the recently discovered Milky Way stellar
cluster Gaia 1 using spectra acquired with the HERMES and AAOmega
spectrographs of the Anglo-Australian Telescope. This cluster had been
previously undiscovered due to its close angular proximity to Sirius,
the brightest star in the sky at visual wavelengths. Our observations
identified 41 cluster members, and yielded an overall metallicity of
[{Fe}/{H}]=-0.13± 0.13 and barycentric radial velocity of
vr = 58.30 ± 0.22 km s-1. These kinematics
provide a dynamical mass estimate of 12.9^{+4.6}_{-3.9}× 10^3
M_{⊙}. Isochrone fits to Gaia, 2MASS, and Pan-STARRS1 photometry
indicate that Gaia 1 is an intermediate age (˜3 Gyr) stellar
cluster. Combining the spatial and kinematic data we calculate Gaia 1
has a circular orbit with a radius of about 12 kpc, but with a large out
of plane motion: z_{max}=1.1^{+0.4}_{-0.3} kpc. Clusters with such
orbits are unlikely to survive long due to the number of plane passages
they would experience.
Original language | English |
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Pages (from-to) | 4087-4098 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 471 |
Issue number | 4 |
DOIs | |
Publication status | Published - 26 Jul 2017 |
Keywords / Materials (for Non-textual outputs)
- catalogues
- Galaxy: general
- Galaxy: structure