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arXiv 1107.4268astro-ph.GAastro-ph.SR
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RAVE中场矮星和巨星的识别

Identification of field dwarfs and giants in RAVE

S. Bilir, S. Karaali, S. Ak, O. Onal, B. Coskunoglu, G. M. Seabroke

摘要:

第二次RAVE数据发布(DR 2)导出log g值,但我们提出了一种更简单,更干净的方法,仅使用大小来识别矮星和巨星,这不需要光谱分析。我们确认了Bilir等人(2006)的方法,该方法通过将其应用于RAVE DR 2,通过它们在J-V二等图中的位置来估计矮星和巨星的数量。与RAVE的log g值相比,它可以有效地估计J-H>0.4时的矮星和巨星的数量。对于J-H<=0.4,其中矮星和亚巨星在J星等直方图中显示出连续的转变,我们使用贝桑松星系模型预测来统计隔离巨星。红巨星和整个样本的巨星百分比分别为85%和34%。如果我们把亚巨星加进去,整个样本中演化恒星的比例将上升到59%。在文献中,我们第一次分析了CHISQ对RAVE的log g值的影响(CHISQ是从RAVE的技术中得到的惩罚chi ^2,该技术是在观测光谱和合成光谱之间找到最佳匹配,以推导恒星参数)。CHISQ值和信噪比均不偏倚RAVE log g值。因此,通过双星等图识别矮星和巨星的方法已经在无偏数据集上得到了验证。

英文摘要:

The second RAdial Velocity Experiment (RAVE) Data Release (DR2) derives log g values but we present a simpler and cleaner method of identifying dwarfs and giants using only magnitudes, which does not require spectroscopic analysis. We confirm the Bilir et al. (2006) procedure which estimates the number of dwarfs and giants via their positions in the J-V two magnitude diagram by applying it to RAVE DR2. It is effective in estimating the number of dwarfs and giants at J-H>0.4 compared to RAVE's log g values. For J-H<=0.4, where dwarfs and subgiants show a continuous transition in the J magnitude histogram, we used the Besancon Galaxy model predictions to statistically isolate giants. The percentages of giants for red stars and for the whole sample are 85% and 34%, respectively. If we add the subgiants, the percentage of evolved stars for the whole sample raises to 59%. For the first time in the literature, we analysed the effect of CHISQ on RAVE's log g values (CHISQ is the penalised chi^2 from RAVE's technique of finding an optimal match between the observed spectrum and synthetic spectra to derive stellar parameters). Neither the CHISQ values nor the signal-to-noise ratio bias RAVE log g values. Therefore the method of identifying dwarfs and giants via the two magnitude diagram has been verified against an unbiased dataset.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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