A NEW CENSUS OF THE VARIABLE STAR POPULATION IN THE GLOBULAR CLUSTER NGC 2419
A NEW CENSUS OF THE VARIABLE STAR POPULATION IN THE GLOBULAR CLUSTER NGC 2419
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DOI：
10.1088/0004-6256/141/3/81
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发表时间：
2010-11
期刊：
影响因子：
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通讯作者：
M. Di Criscienzo;C. Greco;V. Ripepi;G. Clementini;M. Dall' Ora;M. Marconi;I. Musella;L. Federici-L.-Fed
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文献类型：
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作者：
M. Di Criscienzo;C. Greco;V. Ripepi;G. Clementini;M. Dall' Ora;M. Marconi;I. Musella;L. Federici-L.-Fed
本文给出了球状星团NGC 2419中的101颗变星的B、V和I CCD光曲线，其中60颗是新发现的变星，它们是基于伽利略国家望远镜、斯巴鲁望远镜和哈勃太空望远镜获得的数据集。样本包括75颗天琴座RR星（RRab星38颗，RRc星36颗，RRd星1颗），1颗造父变星II星，12颗SX Phoenicis星，2颗δ Scuti星，3个双星系统，5个长周期星和3个分类不确定的星。天琴座RR型星团的脉动特性与Oosterhoff II型星团接近，与低金属丰度和星团水平分支形态相一致，不支持（但不完全排除）NGC 2419起源的河外假说。观测到的天琴座RR星和腓尼基SX星的特性被用来估计星团的变红和距离，使用了许多不同的方法。最终值μ0 (NGC 2419) = 19.71±0.08 mag (D = 87.5±3.3 kpc)， E(B−V) = 0.08±0.01 mag, [Fe/H] = Zinn & West金属丰度指数- 2.1，MV值μ0 (LMC) = 18.52 mag，该值与最新文献对NGC 2419距离的估计基本一致。
We present B, V, and I CCD light curves for 101 variable stars belonging to the globular cluster NGC 2419, 60 of which are new discoveries, based on data sets obtained at the Telescopio Nazionale Galileo, the Subaru telescope, and the Hubble Space Telescope. The sample includes 75 RR Lyrae stars (38 RRab, 36 RRc, and one RRd), one Population II Cepheid, 12 SX Phoenicis variables, two δ Scuti stars, three binary systems, five long-period variables, and three variables of uncertain classification. The pulsation properties of the RR Lyrae variables are close to those of Oosterhoff type II clusters, consistent with the low metal abundance and the cluster horizontal branch morphology, disfavoring (but not totally ruling out) an extragalactic hypothesis for the origin of NGC 2419. The observed properties of RR Lyrae and SX Phoenicis stars are used to estimate the cluster reddening and distance, using a number of different methods. Our final value is μ0 (NGC 2419) = 19.71 ± 0.08 mag (D = 87.5 ± 3.3 kpc), with E(B − V) = 0.08 ± 0.01 mag, [Fe/H] = −2.1 dex on the Zinn & West metallicity scale, and a value of MV that sets μ0 (LMC) = 18.52 mag. This value is in good agreement with the most recent literature estimates of the distance to NGC 2419.