New color-magnitude data for twelve globular clusters

Journal Article · Wed Oct 01 04:00:00 EDT 1975 · Astrophys. J., Suppl. Ser., v. 29, no. 292, pp. 397-429

DOI:https://doi.org/10.1086/190351· OSTI ID:4009254

Harris, W E

This paper presents results of a major program of BV photoelectric and photographic photometry of southern globular clusters. The observational data for this program have been obtained primarily at Las Campanas, Chile, with additional material from Cerro Tololo. New color-magnitude diagrams are presented for 11 clusters (NGC 2808, 4590, 5694, 5824, 6325, 6517, 6681, 6715, 6809, 6864, and 7089); and for one additional cluster (NGC 6266) measurements of the variable stars are listed. For 10 of these objects, no C-M diagrams in the UBV system have previously been published. The features of the diagrams are discussed briefly and used to derive basic information about the clusters, such as their distances, reddenings, and characteristics of the giant and horizontal branches. More extensive discussions are presented for four particularly interesting clusters (NGC 2808, 5694, 6864, and 7089). The first of these (NGC 2808) shows a unique HB morphology, and the third (NGC 6864) is a moderately metal-rich object with an unusually large population of HB stars relative to the giant-branch stars. The second object, NGC 5694, has long been known as a possible ''intergalactic'' cluster that may be escaping from the Galaxy. The information discussed here indicates that NGC 5694 may be gravitationally bound to the Galaxy if the galactic halo within approx.25 kpc is slightly more massive than in conventional models. Finally, NGC 7089 (M2) is shown to have characteristics that modify earlier conclusions from Arp's classical (m/subp// subg/, m/subp//subv/) photometry. (AIP)

• Research Organization: David Dunlap Observatory, Richmond Hill, Ontario, Canada
• Sponsoring Organization: USDOE
• NSA Number: NSA-33-026972
• OSTI ID: 4009254
• Journal Information: Astrophys. J., Suppl. Ser., v. 29, no. 292, pp. 397-429, Journal Name: Astrophys. J., Suppl. Ser., v. 29, no. 292, pp. 397-429; ISSN APJSA
• Country of Publication: United States
• Language: English

Related Subjects

*STAR CLUSTERS-- PHOTOMETRY
640102* --Physics Research--Astrophysics & Cosmology--Stars
BRIGHTNESS
COLOR
DISTANCE
GIANT STARS
N56200* --Physics (Astrophysics & Cosmology)--Stars
VARIABLE STARS