DDO System Research Articles

DDO INTERMEDIATE-BAND PHOTOMETRY OF MOVING-GROUP STARS.

ABSTRACT G and K giant stars in several of Eggen's moving groups have been observed on the DDO system. The cyanogen strength and absolute magnitude calibrations of the system are used to discuss the assignments of the observed stars to moving groups. We are able to confirm the assignment of some 50% of the members of the Hyades moving group and thus to segregate out a more homogeneous sample of Hyades group stars. These stars can be used to recalibrate intrinsic Hyades giant sequences. Less firm conclusions are reached concerning the other, older, groups discussed. Key words: moving groups - abundances - late-type stars

Possible abundance difference among giant stars in NGC 188

view Abstract Citations (40) References (33) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Possible abundance difference among giant stars in NGC 188. McClure, R. D. Abstract B and V observations of 10 stars on the giant branch of NGC 188 confirm the large scatter shown by the color-magnitude diagram of Sandage and Eggen and Sandage. Intermediate-band photometry on the DDO system indicates that this scatter is intrinsic to the stars and may be due to differences in heavy-element abtindance. The intermediate-band photometry has been used to obtain an independent value of reddening for the cluster and confirms the low value obtained by Eggen and Sandage. The mean value of the cyanogen anomaly CN for the giants in NGC 188 is identical to that for solar-neighborhood field giants, and weaker than that for the Hyades cluster giants. Subject headings: abundances, stellar - late-type stars - open clusters Publication: The Astrophysical Journal Pub Date: December 1974 DOI: 10.1086/153252 Bibcode: 1974ApJ...194..355M full text sources ADS | data products SIMBAD (12) GCPD (1)

Cyanogen-Band Strengths of Giant Stars in 47 Tucanae

view Abstract Citations (48) References (12) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Cyanogen-Band Strengths of Giant Stars in 47 Tucanae McClure, Robert D. ; Osborn, Wayne Abstract Photoelectric photometry on the DDO system has been obtained for stars on the giant branch of the globular cluster 47 Tucanae in order to obtain a quantitative measure of the cyanogen-band strength. A value of metal abundance inferred from the CN strengths is in very good agreement with that inferred from the ultraviolet excesses. This value is approximately 1/4-1/5 Hyades abundance. Subject headings: abundances, stellar - globular clusters - late-type stars - molecules Publication: The Astrophysical Journal Pub Date: May 1974 DOI: 10.1086/152817 Bibcode: 1974ApJ...189..405M full text sources ADS | data products SIMBAD (1) GCPD (1)

Variation of the Nitrogen Abundance among Population II Objects

view Abstract Citations (51) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Variation of the Nitrogen Abundance among Population II Objects Hartwick, F. D. A. ; McClure, R. D. Abstract Intermediate-band photometry, on the DDO system, of individual giant stars in the anomalous globular cluster NGC 7006 confirm the weak-metal4ined character exhibited by integrated light observations but indicate anomalously strong cyanogen bands. These results are consistent with the possibility that the nitrogen abundance is the elusive second parameter affecting the color-magnitude diagrams of globular clusters. Publication: The Astrophysical Journal Pub Date: September 1972 DOI: 10.1086/181019 Bibcode: 1972ApJ...176L..57H full text sources ADS | data products SIMBAD (2)