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Title: Main sequence of the metal-poor globular cluster M30 (NGC 7099)

We present photographic photometry for 673 stars in the metal-poor globular cluster M30 (NGC 7099). The Racine wedge was used with the CTIO 1-m Yale telescope (..delta..m=3/sup m/.60), the CTIO 4-m telescope (..delta..m=6/sup m/.83), and the ESO 3.6-m telescope (..delta..m=4/sup m/.12) to extend the photoelectric limit from Vapprox. =16.3 to Vapprox. =20.4. For the main-sequence turn-off, we have determined its position to lie at V=18.4 +- 0.1 (m.e.) and B-V=0.49 +- 0.03 (m.e.). From these values, we calculate the intrinsic values M/sub v/ =3.87 and (B-V)/sub 0/=0.47. For the cluster as a whole, we derive a distance modulus (m-M)/sub V/=14.53 +- 0.15 and reddening E(B-V)=0.02 +- 0.02. Using the models of Iben and Rood (Astrophys. J. 159, 605 (1970)) and the isochrones of Demarque and McClure ((1977), in Evolution of Galaxies and Stellar Populations, edited by B. Tinsley and R. B. Larson (Yale University Observatory, New Haven), p. 199), we deduce the cluster's age to be 14.5( +- 4.0) x 10/sup 9/ yr. The large uncertainty in this value emphasizes the dire need for more work on cluster evolution.
Authors:
;
Publication Date:
OSTI Identifier:
7096383
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astron. J.; (United States); Journal Volume: 85:10
Research Org:
Instituto Isaac Newton, Ministerio de Educacion de Chile, Casilla 8-9, Correo 9, Santiago, Chile
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; STAR CLUSTERS; HERTZSPRUNG-RUSSELL DIAGRAM; AGE ESTIMATION; DISTANCE; MAIN SEQUENCE STARS; PHOTOMETRY; DIAGRAMS; STARS 640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar, Radio & X-Ray Sources