Absolute Proper Motions and Chemical Abundances of Stars Along the Sagittarius Trailing Tidal Tail

Astronomy and Astrophysics – Astronomy

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

1

Scientific paper

We show results from our deep proper-motion survey of Kapteyn's Selected Areas (SAs; Casetti-Dinescu et al. 2006, AJ,132,2082), with a focus on fields that intersect the Sagittarius (Sgr) trailing tidal stream. Our data set, derived from matched, deep photographic plate pairs taken nearly 100 years apart, provides a unique window on the motions of stars in these SA fields. We find the signature of a common-motion population among our accurate proper motions of stars in five of these fields, as well as corresponding stellar excesses which are identified as stellar debris from the disrupted Sgr dwarf. Spectroscopic follow-up confirms that these stars are Sgr members, and the resultant radial velocities and spectroscopic parallaxes are combined with proper motions to derive full space motions of 30-100 tidal stream members per field. These kinematical data are compared to the predictions of the Law et al. (2009, ApJL,703,67) models of Sgr disruption, which have thus far reproduced most observed features of the Sgr stream, and have also constrained the triaxial shape of the Milky Way's dark matter halo. We also derive low-resolution spectroscopic abundances along this stretch of the Sgr stream, and explore the stream metallicity gradient reported by Chou et al. (2007, ApJ,670,346). Majewski et al. (2006, ApJL,627,25) showed that because the Sgr debris plane is nearly coincident with the Galactic X-Z Cartesian plane, proper motions in the portion of the Sgr trailing tail in our study almost entirely reflect the solar motion, and can be used to make a direct measurement of the rotation speed at the Solar circle (the "Local Standard of Rest") almost completely independent of the Sun's distance from the Galactic center. Here, we report our derived constraints on the solar motion from absolute proper motions of Sgr debris in our SA fields.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Absolute Proper Motions and Chemical Abundances of Stars Along the Sagittarius Trailing Tidal Tail 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 Absolute Proper Motions and Chemical Abundances of Stars Along the Sagittarius Trailing Tidal Tail, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Absolute Proper Motions and Chemical Abundances of Stars Along the Sagittarius Trailing Tidal Tail will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-961812

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.