arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1701.04791astro-ph.SR
收藏

确定星震目标的恒星参数:超越标度关系的使用

Determining stellar parameters of asteroseismic targets: going beyond the use of scaling relations

Thaíse S. Rodrigues, Diego Bossini, Andrea Miglio, Léo Girardi, Josefina Montalbán, Arlette Noels, Michele Trabucchi, Hugo Rodrigues Coelho, Paola Marigo

摘要:

天文地震参数使我们能够测量在银河系中观测到的场巨星的基本恒星属性。到目前为止,大多数这样的确定是基于简单的标度关系,涉及大的频率间隔Δν和最大功率的频率ν $_{max}$。在这项工作中,我们实现了Δν和周期间隔,ΔP,计算沿着恒星演化轨迹的详细网格,恒星等时线,因此在贝叶斯方法的参数估计。用合成数据进行的试验表明,只要有精确的地震参数,可以分别以5%和19%的典型精度确定质量和年龄。加上恒星光度的独立信息,这些值可以分别下降到3%和10%。应用这些方法对NGC 6819巨星产生的平均年龄与等时线拟合的结果一致,并且没有证据表明RGB和RC星之间存在系统差异。然而,NGC 6819恒星的年龄分散度比预期的要大,至少部分的分散度是由于经历了质量转移事件的恒星。

英文摘要:

Asteroseismic parameters allow us to measure the basic stellar properties of field giants observed far across the Galaxy. Most of such determinations are, up to now, based on simple scaling relations involving the large frequency separation, Δν, and the frequency of maximum power, ν$_{max}$. In this work, we implement Δν and the period spacing, ΔP, computed along detailed grids of stellar evolutionary tracks, into stellar isochrones and hence in a Bayesian method of parameter estimation. Tests with synthetic data reveal that masses and ages can be determined with typical precision of 5 and 19 per cent, respectively, provided precise seismic parameters are available. Adding independent information on the stellar luminosity, these values can decrease down to 3 and 10 per cent respectively. The application of these methods to NGC 6819 giants produces a mean age in agreement with those derived from isochrone fitting, and no evidence of systematic differences between RGB and RC stars. The age dispersion of NGC 6819 stars, however, is larger than expected, with at least part of the spread ascribable to stars that underwent mass-transfer events.

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。

↑