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arXiv 2006.16610astro-ph.SR
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在盖亚数据发布2中预测的银河造父变星质量

Predicted masses of Galactic Cepheids in the Gaia Data Release 2

Marcella Marconi, Giulia De Somma, Vincenzo Ripepi, Roberto Molinaro, Ilaria Musella, Silvio Leccia, Maria Ida Moretti

备注：
6 pages, 3 figures, 2 tables. Accepted for publication in ApJ Letters
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摘要：

最近计算的非线性对流脉动模型的银河造父变星的基础上，跨越宽范围的输入恒星参数，我们推导出理论的质量依赖的周期-Weseneirs关系在盖亚带，即$G$，$G_{BP}$和$G_{RP}$，被发现几乎是独立的假设效率的超绝热对流。盖亚数据发布2银河造父变星数据库的选定子样本的应用程序，使我们能够获得质量依赖的估计，他们的个人距离。通过将它们与从盖亚推断出的天体测量值相匹配，我们能够评估每个行星的个体质量。F和FO衰变子的推断质量分布分别在5.6 $M_{\odot}$和5.4 $M_{\odot}$附近达到峰值。如果估计的盖亚视差偏移$<Δ\varpi>$ =0.046 mas被应用于盖亚视差，然后再将它们与理论值重合，则发现推断的质量分布向较低质量移动，即F和FO视差分别为5.2 $\sim$和5.1 $M_{\odot}$。在我们的样本中的一个子集的二进制造父变星的恒星质量的独立评估的比较，似乎支持当前的理论方案的预测能力。通过使我们的质量测定与这些文献值重合，我们得出了适用于Gaia DR 2弛豫的平均偏移的独立估计值，$<Δ\varpi>$ =0.053 $\pm$ 0.029 mas，略高，但与Riess 2018值的误差一致。

英文摘要：

On the basis of recently computed nonlinear convective pulsation models of Galactic Cepheids, spanning wide ranges of input stellar parameters, we derive theoretical mass-dependent Period-Wesenheit relations in the Gaia bands, namely $G$, $G_{BP}$ and $G_{RP}$, that are found to be almost independent of the assumed efficiency of super-adiabatic convection. The application to a selected sub-sample of Gaia Data Release 2 Galactic Cepheids database allows us to derive mass-dependent estimates of their individual distances. By imposing their match with the astrometric values inferred from Gaia, we are able to evaluate the individual mass of each pulsator. The inferred mass distribution is peaked around 5.6$M_{\odot}$ and 5.4$M_{\odot}$ for the F and FO pulsators, respectively. If the estimated Gaia parallax offset $<Δ\varpi>$=0.046 mas is applied to Gaia parallaxes before imposing their coincidence with the theoretical ones, the inferred mass distribution is found to shift towards lower masses, namely $\sim$5.2$M_{\odot}$ and 5.1$M_{\odot}$ for the F and FO pulsators, respectively. The comparison with independent evaluations of the stellar masses, for a subset of binary Cepheids in our sample, seems to support the predictive capability of current theoretical scenario. By forcing the coincidence of our mass determinations with these literature values we derive an independent estimate of the mean offset to be applied to Gaia DR2 parallaxes, $<Δ\varpi>$=0.053 $\pm$ 0.029 mas, slightly higher but in agreement within the errors with Riess2018 value.

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