Progress on the calibration of surface brightness–color relations for early- and late-type stars
Progress on the calibration of surface brightness–color relations for early- and late-type stars
复制标题
早晚型恒星表面亮度-颜色关系标定研究进展
DOI：
10.1051/0004-6361/202140763
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发表时间：
2021
影响因子：
6.5
通讯作者：
Pietrzynski, G.
中科院分区：
文献类型：
--
作者：
Salsi, A.;Nardetto, N.;Mourard, D.;Graczyk, D.;Taormina, M.;Creevey, O.;Hocdé, V.;Morand, F.;Perraut, K.;Pietrzynski, G.
背景表面亮度-颜色关系(SBCR)被广泛用于估计角直径和推导恒星性质。它们对于推算早型和晚型食双星的河外距离，或者潜在地提取拥有行星的晚型恒星的行星参数是至关重要的。到目前为止，已经实现了各种SBCR，但在精度和准确度方面，文献中仍然存在很大的差异。目的我们的目标是利用选择标准，基于恒星特性，结合均匀干涉角径测量，开发针对早期B型和A型恒星的精确SBCR。我们还改进了迟型恒星的SBCR，特别是在GaI光度波段。方法我们用安装在Chara阵列上的织女星干涉仪观测了18颗早型恒星。然后，我们对光度测量和恒星特征诊断应用了额外的标准，以建立SBCR。结果我们为亚巨星和矮星早期类型的恒星校准了SBCR。该关系式的均方根为mAG，角直径估计的平均精度为2.3%，V−K<；−0.2mag为3.1%，V−K>；−0.2mag为1.8%。我们发现，Johnson-K和2MASS-Ksphotometry之间的转换是早期类型恒星的一个关键问题。在这一结果之后，我们通过使用转换后的Johnson-Kor 2MASS-Ksphotometry来校准我们以前的晚型恒星的SBCR。我们还改进了基于GaI光度法的SBCR的定标方法。对于晚型恒星，我们的SBCR对角直径的预期精度在1.0%到2.7%之间。结论通过对早型星角直径的估计达到2.3%的精度，利用早型食双星确定河外距离，例如M31和M33星系，已经取得了重大进展。
ContextSurface brightness-color relations (SBCRs) are widely used for estimating angular diameters and deriving stellar properties. They are critical to derive extragalactic distances of early-type and late-type eclipsing binaries or, potentially, for extracting planetary parameters of late-type stars hosting planets. Various SBCRs have been implemented so far, but strong discrepancies in terms of precision and accuracy still exist in the literature.AimsWe aim to develop a precise SBCR for early-type B and A stars using selection criteria, based on stellar characteristics, and combined with homogeneous interferometric angular diameter measurements. We also improve SBCRs for late-type stars, in particular in theGaiaphotometric band.MethodsWe observed 18 early-type stars with the VEGA interferometric instrument, installed on the CHARA array. We then applied additional criteria on the photometric measurements, together with stellar characteristics diagnostics in order to build the SBCRs.ResultsWe calibrated a SBCR for subgiant and dwarf early-type stars. The RMS of the relation is mag, leading to an average precision of 2.3% on the estimation of angular diameters, with 3.1% forV−K< −0.2 mag and 1.8% forV−K> −0.2 mag. We found that the conversion between Johnson-Kand 2MASS-Ksphotometries is a key issue for early-type stars. Following this result, we have revisited our previous SBCRs for late-type stars by calibrating them with either converted Johnson-Kor 2MASS-Ksphotometries. We also improve the calibration of these SBCRs based on theGaiaphotometry. The expected precision on the angular diameter using our SBCRs for late-type stars ranges from 1.0 to 2.7%.ConclusionsBy reaching a precision of 2.3% on the estimation of angular diameters for early-type stars, significant progress has been made to determine extragalactic distances, such as M31 and M33 galaxies, using early-type eclipsing binaries.