论文标题
分析银河古典头的光谱能量分布
Analysing the spectral energy distributions of Galactic classical Cepheids
论文作者
论文摘要
（删节）光谱能量分布（SED）是为477个经典头虫（CCS）的样品构建的。 SEDS配备了灰尘辐射转移代码。四颗星显示出较大的中央或远红外过量，然后配件包括灰尘成分。这些包括众所周知的RS PUP情况，以及（可能）II型头孢虫（T2CS），Au PEG，QQ Per和FQ lac的三个恒星。 样品的其余部分拟合了出色的光球，以得出最合适的光度和有效温度。距离和红色是从文献中汲取的。将恒星绘制在Hertzsprung-Russell图中，并将其与头孢虫和理论不稳定性条的进化轨道进行了比较。对于绝大多数恒星，HRD中的位置与CC或T2C的不稳定性条一致。大约5％的恒星是异常值，因为它们比预期的要热得多或凉爽。与光谱法衍生的有效温度的比较表明，在某些情况下，光学衍生的温度不正确，并且这很可能与不正确采用的变红有关。 在这项工作中，研究了一些众所周知的头孢虫的文献中提出的那样。首先，这是通过使用大约十二颗恒星的样品来完成的，其中有中红外光谱。其次，所有恒星的SED都配备了灰尘模型，以查看是否可以获得具有统计学意义的更好拟合度。将结果与最近的工作进行了比较。仅基于光度法SED，提出了八个用于表现NIR过量的新候选者。需要获得中红外光谱以确认这一多余的光谱。最后，针对超过370个基本模式CCS的样本提出了周期量仪的光度和周期 - 拉迪乌斯关系。
(abridged) Spectral energy distributions (SEDs) were constructed for a sample of 477 classical cepheids (CCs). The SEDs were fitted with a dust radiative transfer code. Four stars showed a large mid- or far-infrared excess and the fitting then included a dust component. These comprise the well-known case of RS Pup, and three stars that are (likely) Type-II cepheids (T2Cs), AU Peg, QQ Per, and FQ Lac. The remainder of the sample was fitted with a stellar photosphere to derive the best-fitting luminosity and effective temperature. Distance and reddening were taken from the literature. The stars were plotted in a Hertzsprung-Russell diagram and compared to evolutionary tracks for cepheids and theoretical instability strips. For the large majority of stars, the position in the HRD is consistent with the instability strip for a CC or T2C. About 5% of the stars are outliers in the sense that they are much hotter or cooler than expected. A comparison to effective temperatures derived from spectroscopy suggests in some cases that the photometrically derived temperature is not correct and that this is likely linked to an incorrectly adopted reddening. In this work the presence of a small NIR excess, as has been proposed in the literature for a few well-known cepheids, is investigated. Firstly, this was done by using a sample of about a dozen stars for which a mid-infrared spectrum is available. Secondly, the SEDs of all stars were fitted with a dust model to see if a statistically significant better fit could be obtained. The results were compared to recent work. Eight new candidates for exhibiting a NIR excess are proposed, solely based on the photometric SEDs. Obtaining mid-infrared spectra would be needed to confirm this excess. Finally, period-bolometric luminosity and period-radius relations are presented for samples of over 370 fundamental-mode CCs.
