Inspecting the Cepheid parallax of pulsation using Gaia EDR3 parallaxes: Projection factor and period-luminosity and period-radius relations
Inspecting the Cepheid parallax of pulsation using Gaia EDR3 parallaxes: Projection factor and period-luminosity and period-radius relations
复制标题
使用 Gaia EDR3 视差检查造父变星脉动视差：投影因子以及周期-光度和周期-半径关系
DOI：
10.1051/0004-6361/202141680
复制
发表时间：
2021
影响因子：
6.5
通讯作者：
Gieren, W.
中科院分区：
文献类型：
--
作者：
Trahin, B.;Breuval, L.;Kervella, P.;Mérand, A.;Nardetto, N.;Gallenne, A.;Hocdé, V.;Gieren, W.
造父变星作为距离尺度的主要支柱，由于它们的周期-光度关系，在我们理解宇宙距离尺度时起着至关重要的作用。目的利用第三代造父变星(EDR3)的高精度视差，对造父变星的周期-光度、周期-半径关系、周期-半径关系以及周期顶因子的关系进行定标。方法利用脉动恒星光谱光干涉算法(SPIP)，结合变星的各种可用数据(多波段、多色、径向速度、有效温度、有效温度)，研究周期顶因子与周期顶因子的关系结果我们给出了63颗银河系造父变星的SPIP模型。采用GaiaEDR3视差作为最佳数据集的输入，我们得到了这些恒星的半径、多波段视星等、有效温度、色差、周期变化、傅里叶参数和投影因子等参数的一致值。结论利用最好的数据集和最精确的银河系造父变星距离，我们得到了周期-光度和周期-半径关系的新定标：MKS=−5.529±0.015− 3.141±0.050(logP− 0.9)，logR=1.763±0.003+ 0.653±0.012(logP− 0.9)。在研究了投影因子对恒星参数的依赖关系后，我们发现它的值有很高的离散度，没有证据表明它与周期或任何其他参数，如径向速度、温度或金属丰度等相关。经统计学处理，p因子的平均值为p= 1.26 ± 0.07，但一致性较差(σ= 为0.15)。在p因子与其他量之间没有任何明确的相关性的情况下，假设p因子可以取宽度为0.15的频带中的任何值，则得到最佳的一致性。这一结果突显了进一步研究p因子背后的物理学的必要性。
ContextAs primary anchors of the distance scale, Cepheid stars play a crucial role in our understanding of the distance scale of the Universe because of their period-luminosity relation. Determining precise and consistent parameters (radius, temperature, color excess, and projection factor) of Cepheid pulsating stars is therefore very important.AimsWith the high-precision parallaxes delivered by the early thirdGaiadata release (EDR3), we aim to derive various parameters of Cepheid stars in order to calibrate the period-luminosity and period-radius relations and to investigate the relation of period top-factor.MethodsWe applied an implementation of the parallax-of-pulsation method through the algorithm called spectro-photo-interferometry of pulsating stars (SPIPS), which combines all types of available data for a variable star (multiband and multicolor photometry, radial velocity, effective temperature, and interferometry measurements) in a global modeling of its pulsation.ResultsWe present the SPIPS modeling of a sample of 63 Galactic Cepheids. AdoptingGaiaEDR3 parallaxes as an input associated with the best available dataset, we derive consistent values of parameters for these stars such as the radius, multiband apparent magnitudes, effective temperatures, color excesses, period changes, Fourier parameters, and the projection factor.ConclusionsUsing the best set of data and the most precise distances for Milky Way Cepheids, we derive new calibrations of the period-luminosity and period-radius relations:MKS= −5.529±0.015− 3.141±0.050(logP− 0.9) and logR= 1.763±0.003+ 0.653±0.012(logP− 0.9). After investigating the dependences of the projection factor on the parameters of the stars, we find a high dispersion of its values and no evidence of its correlation with the period or with any other parameters such as radial velocity, temperature, or metallicity. Statistically, thep-factor has an average value ofp= 1.26 ± 0.07, but with an unsatisfactory agreement (σ= 0.15). In absence of any clear correlation between thep-factor and other quantities, the best agreement is obtained under the assumption that thep-factor can take any value in a band with a width of 0.15. This result highlights the need for a further examination of the physics behind thep-factor.