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|New Photometric Data of Old Open Clusters in the Anti-Galactic Center Region|
We present new photometric data for 14 galactic open clusters taken bythe 65cm telescope at Gunma Astronomical Observatory. They were in theanti-galactic center region selected from the Catalog of Open ClusterData (Lyngå 1987). We estimated the parameters of the clusters,i.e., age, metallicity, distance, and reddening, by fitting Padovaisochrones to the color-magnitude diagram. While no clusters were datedto be as old as young globular clusters, 13 clusters out of 14 are olderthan 1Gyr, ranging up to ˜ 3.6 Gyr. Bearing in mind that out ofapproximately 500 clusters dated so far, only 40 clusters are older than1Gyr, our sample is exclusively dominated by old clusters. Four clusterswere found away from the metallicity gradient curve and age-metallicityrelation so far delineated. Especially, 3 metal-rich clusters in theouter disk (Berkeley 36, Biurakan 11, and Biurakan 13) provide evidenceagainst the picture advocated by Twarog etal. (1997, AJ, 114, 2556) thatthere is a break in the metallicity distribution at rGC = 10kpc and that the outer disk is chemically less evolved than in the innerdisk.
|The Galactic System of Open Star Clusters: A Personal Perspective|
Technology is now allowing for the investigation of star clustersoutside of the Milky Way. As attention turns to the extragalactic starclusters, a perception that the system of star clusters in the Milky Wayis well understood may grow, resulting in the neglect of these importantobjects. In this review, the status of our understanding of the MilkyWay's open star cluster population will be discussed. Specifically, Iwill attempt to illustrate not only the important information that canand must be learned from these nearby star clusters, but also the degreeto which our understanding of the Galactic open clusters remainsincomplete.
|Classification of open star clusters|
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