SIMBAD references

1999ApJ...518..262S - Astrophys. J., 518, 262-283 (1999/June-2)

Wide-field CCD photometry of the globular cluster M30.

SANDQUIST E.L., BOLTE M., LANGER G.E., HESSER J.E. and MENDES DE OLIVEIRA C.

Abstract (from CDS):

We present new VI photometry for the halo globular cluster M30 (NGC 7099=C2137-174) and compute luminosity functions (LFs) in both bands for samples of about 15,000 hydrogen-burning stars from near the tip of the red giant branch (RGB) to over 4 mag below the main-sequence (MS) turnoff (TO). We confirm previously observed features of the LF that are at odds with canonical theoretical predictions: an excess of stars on subgiant branch (SGB) approximately 0.4 mag above the turnoff and an excess number of RGB stars relative to MS stars. Based on subdwarfs with Hipparcos-measured parallaxes, we compute apparent distance moduli of (m-M)V=14.87±0.12 and 14.65±0.12 for reddenings of E(V-I)=0.06 and 0.02, respectively. The implied luminosity for the horizontal branch (HB) at these distances is MHBV=0.11 and 0.37 mag. The two helium indicators we have been able to measure (R and Δ) both indicate that M30's helium content is high relative to those in other clusters of similar metallicity. M30 has a larger value for the parameter ΔVHBTO than any of the other similarly metal-poor clusters for which this quantity can be reliably measured. This suggests that M30 has either a larger age or higher helium content than all of the other metal-poor clusters examined. The color-difference method for measuring relative ages indicates that M30 is coeval with the metal-poor clusters M68 and M92.

Abstract Copyright:

Journal keyword(s): globular clusters: individual (M30) - Stars: Hertzsprung-Russell Diagram - Stars: Abundances - Stars: Distances - Stars: Evolution

VizieR on-line data: <Available at CDS (J/ApJ/518/262): table1.dat>

Nomenclature: Table 1: Cl* NGC 7099 SBL NNNNN N=25279 among 46605.

Status at CDS : All or part of tables of objects will not be ingested in SIMBAD.

Simbad objects: 12

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