NEW PROPER MOTIONS IN THE GLOBULAR-CLUSTER M5

Authors
Citation
Rf. Rees, NEW PROPER MOTIONS IN THE GLOBULAR-CLUSTER M5, The Astronomical journal, 106(4), 1993, pp. 1524
Citations number
29
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
00046256
Volume
106
Issue
4
Year of publication
1993
Database
ISI
SICI code
0004-6256(1993)106:4<1524:NPMITG>2.0.ZU;2-U
Abstract
New proper motions have been derived from reductions of PDS microdensi tometer scans of 17 Yerkes refractor plates spanning an epoch range of 88 years for 515 stars down to V approximately 15.6 in the region of the globular cluster M5. Photographic photometry in B and V has been o btained for these stars from these scans and scans of six Yerkes refle ctor plates. The present proper motions have significantly improved pr ecision compared to Cudworth [AJ, 84, 1866 (1979)]. Membership probabi lities derived from the new proper motions are largely in agreement wi th those from Cudworth's study, but this paper includes nearly 200 add itional stars, many of which are probable members. A color-magnitude d iagram of probable members is presented and discussed, as well as comp arisons to previous photometry. All but two of the previously known or suspected variables are found to be highly probable members. These pr oper motions have been used by Cudworth & Hanson [AJ, 105, 168 (1993)] to derive a large space velocity for M5, implying that it is a rich o uter halo cluster on an eccentric orbit near perigalacticon. These mot ions will be used in a forthcoming paper to explore the internal dynam ics of M5, including a derivation of the cluster distance by compariso n of the proper motion and radial velocity dispersions.