Variable Stars in the Newly Discovered Milky Way Dwarf Spheroidal Satellite Canes Venatici I
Variable Stars in the Newly Discovered Milky Way Dwarf Spheroidal Satellite Canes Venatici I
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DOI：
10.1086/529137
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发表时间：
2007-09
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通讯作者：
C. Kuehn;K. Kinemuchi;V. Ripepi;G. Clementini;M. Dall’ora;L. Di Fabrizio;C. Rodgers;C. Greco;M. Marconi;I. Musella;H. Smith;M. Catelán;T. Beers;B. Pritzl
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作者：
C. Kuehn;K. Kinemuchi;V. Ripepi;G. Clementini;M. Dall’ora;L. Di Fabrizio;C. Rodgers;C. Greco;M. Marconi;I. Musella;H. Smith;M. Catelán;T. Beers;B. Pritzl
我们在最近发现的Canes Venatici （CVn I）矮球状星系的84个候选变量中确定了23颗RR Lyrae恒星和3颗可能的异常造父变星（ACs）。18颗RRab型恒星的平均周期，⟨Pab⟩= 0.60±0.01天，以及这些恒星在周期-振幅图中的位置表明CVn I可能是一个ooster霍夫-中间系统。天琴座RR星的平均视星等⟨V⟩= 22.17±0.02等，给出的距离为210+ 7−5 kpc，采用变红的E(B−V) = 0.03等。我们给出CVn I的B， V颜色星等图（CMD），达到V ~ 25等，并显示该星系主要有老恒星群，金属丰度接近[Fe/H] = -2.0指数。红巨星分支的宽度和候选ac在CMD上的位置可能表明该星系拥有一个复杂的恒星群，恒星年龄从~13 Gyr到~0.6 Gyr不等。
We have identified 23 RR Lyrae stars and three possible anomalous Cepheids (ACs) among 84 candidate variables in the recently discovered Canes Venatici I (CVn I) dwarf spheroidal galaxy. The mean period of 18 RRab type stars, ⟨ Pab⟩ = 0.60 ± 0.01 days, and the location of these stars in the period-amplitude diagram suggest that CVn I is likely an Oosterhoff-intermediate system. The average apparent magnitude of the RR Lyrae stars, ⟨ V⟩ = 22.17 ± 0.02 mag, gives a distance of 210+ 7−5 kpc, for an adopted reddening E(B − V) = 0.03 mag. We present a B, V color-magnitude diagram (CMD) of CVn I that reaches V ∼ 25 mag, and shows that the galaxy has a mainly old stellar population with a metal abundance near [Fe/H] = –2.0 dex. The width of the red giant branch and the location of the candidate ACs on the CMD may indicate that the galaxy hosts a complex stellar population with stars from ~13 Gyr to as young as ~0.6 Gyr.