2011/03/09 by K. Zloczewski, J. Kaluzny, I. B. Thompson · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Blue straggler #Galaxy #Globular cluster #Proper motion #Scientific Research and Discoveries #Star cluster #Stars #Stellar, planetary, and galactic studies #Telescope #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1111/j.1365-2966.2011.18673.x
12 figures and 4 tables, accepted for publication in MNRAS Main Journal; full PM catalogue (Table 3) at http://case.camk.edu.pl
arxiv created 2011/03/09 · openalex publication_date 2011/06/03 · arxiv updated 2015/05/27 · openalex created_date 2019/06/27 · openalex updated_date 2026/08/05
We have derived the absolute proper motion (PM) of the globular cluster M55 using a large set of CCD images collected with the du Pont telescope between 1997 and 2008. We find (μα cos δ, μδ) = (−3.31 ± 0.10, −9.14 ± 0.15) mas yr−1 relative to background galaxies. Membership status was determined for 16 945 stars with 14 < V < 21 from the central part of the cluster. The PM catalogue includes 52 variables, of which 43 are probable members of M55. This sample not only is dominated by pulsating blue straggler stars, but also includes five eclipsing binaries, three of which are main-sequence objects. The survey also identified several candidate blue, yellow and red straggler stars belonging to the cluster. We detected 15 likely members of the Sgr dSph galaxy located behind M55. The average PM for these stars was measured to be (μα cos δ, μδ) = (−2.23 ± 0.14, −1.83 ± 0.24) mas yr−1.