发表机构
CHRIST (Deemed to be University); Tata Institute of Fundamental Research; Indian Institute of Astrophysics; Maharaja Ranjit Singh Punjab Technical University; North-West University（克里斯（被视为大学）大学; 塔塔基础研究所; 印度天体物理研究所; 兰吉特·辛格王公旁遮普技术大学; 西北大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过结合天体测量、测光建模和光谱分析，识别出仙王座恒星形成区中一个特殊对象Gaia DR3 2205212960562531328，发现其由A0型前主序星和sdB伴星组成，为系统搜索此类不可见伴星双星系统开辟了新途径。
AI 中文摘要
光谱中的发射线和红外（IR）波段光谱能量分布（SED）中观测到的过量发射是恒星周围环境中吸积活动以及气体和尘埃存在的关键指标。随着吸积在数百万年内逐渐停止，H$\alpha$发射减弱。然而，红外过量与可忽略的H$\alpha$发射相结合，也可能表明某些密近双星系统，其中环双星盘对观测到的过量有贡献。此外，在未分辨的双星中，伴星可能对测光有贡献，导致参数测量不准确，并在颜色-星等图（CMD）中产生偏移位置。我们从仙王座恒星形成区（SFRs）的巡天中识别出一个测光上特殊的对象，即Gaia DR3 2205212960562531328，它表现出相对于其在CMD中预期位置的偏移，如Gaia光学测光所示。这一特殊性推动了我们的研究，促使我们通过一种结合天体测量精度、测光建模和光谱研究的方法进行调查。该源的Gaia XP光谱显示出系统性蓝过量，表明存在一个额外的更热的未分辨成分。双成分SED建模得出一个$T_{\rm eff}\sim27000$ K且$\log g\ge4.5$的伴星，与sdB星一致。进一步的CMD和光谱分析支持一个由A0型前主序星和sdB伴星组成的双星系统。此外，ZTF测光显示出0.498天周期性的初步证据。这项研究为系统搜索类似的双星系统铺平了道路，这些系统否则将无法被识别。
英文摘要
Emission lines in the spectrum and the excess seen in the spectral energy distribution (SED) at infrared (IR) wavelengths serve as crucial indicators of accretion activity and the presence of gas and dust in the circumstellar environment of a young star. As accretion ceases over several million years, the H$α$ emission diminishes. However, IR excess combined with negligible H$α$ emission could also extend to indicate certain close binary systems, where a circumbinary disk contributes to the observed excess. Additionally, in unresolved binaries, companion stars can contribute to the photometry, leading to inaccuracies in parameter measurements and skewed positions in the color-magnitude diagram (CMD). We identify a photometrically peculiar object from a survey of the Cepheus star-forming regions (SFRs), Gaia DR3 2205212960562531328, exhibiting a shift from its expected position in the CMD, as indicated by the Gaia optical photometry. This peculiarity drives our research, prompting an investigation through an approach that combines astrometric accuracy, photometric modeling and spectroscopic studies. The Gaia XP spectrum of the source shows a systematic blue excess, indicating an additional hotter unresolved component. Two-component SED modelling yields a companion with $T_{\rm eff}\sim27000$ K and $\log g\ge4.5$, consistent with sdB stars. Further CMD and spectroscopic analyses support a binary system consisting of an A0-type PMS star with an sdB companion. In addition, ZTF photometry shows tentative evidence for a periodicity of 0.498 days. This study paves the way for a systematic search of similar binary systems that would otherwise remain unidentified.
CommentsAccepted for publication in Astrophysics and Space Science
