The velocity distribution of nearby stars from Hipparcos data II. The nature of the low-velocity moving groups

Details The velocity distribution of nearby stars from Hipparcos data II. The nature of the low-velocity moving groups The velocity distribution of nearby stars from Hipparcos data II. The nature of the low-velocity moving groups

2009-12-17

arxiv.org/abs/0912.3262v2

Astrophys.J.717:617-639,2010

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

Scientific paper

10.1088/0004-637X/717/2/617

The velocity distribution of nearby stars contains many "moving groups" that are inconsistent with the standard assumption of an axisymmetric, time-independent, and steady-state Galaxy. We study the age and metallicity properties of the low-velocity moving groups based on the reconstruction of the local velocity distribution in Paper I of this series. We perform stringent, conservative hypothesis testing to establish for each of these moving groups whether it could conceivably consist of a coeval population of stars. We conclude that they do not: the moving groups are not trivially associated with their eponymous open clusters nor with any other inhomogeneous star formation event. Concerning a possible dynamical origin of the moving groups, we test whether any of the moving groups has a higher or lower metallicity than the background population of thin disk stars, as would generically be the case if the moving groups are associated with resonances of the bar or spiral structure. We find clear evidence that the Hyades moving group has higher than average metallicity and weak evidence that the Sirius moving group has lower than average metallicity, which could indicate that these two groups are related to the inner Lindblad resonance of the spiral structure. Further we find weak evidence that the Hercules moving group has higher than average metallicity, as would be the case if it is associated with the bar's outer Lindblad resonance. The Pleiades moving group shows no clear metallicity anomaly, arguing against a common dynamical origin for the Hyades and Pleiades groups. Overall, however, the moving groups are barely distinguishable from the background population of stars, raising the likelihood that the moving groups are associated with transient perturbations. [abridged]

Affiliated with

Also associated with

No associations

Rating

The velocity distribution of nearby stars from Hipparcos data II. The nature of the low-velocity moving groups does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The velocity distribution of nearby stars from Hipparcos data II. The nature of the low-velocity moving groups, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The velocity distribution of nearby stars from Hipparcos data II. The nature of the low-velocity moving groups will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-348547