BLG723.31.34651 为一充满洛希瓣的食双星，由 sdOB 型热亚矮星与白矮星（WD）组成
BLG723.31.34651 as an eclipsing Roche lobe-filling sdOB+WD binary
AI总结：
本研究通过多波段测光与光谱观测，分析第四例充满洛希瓣的食双星 BLG723.31.34651，明确其由 sdOB 型热亚矮星与 WD 组成，揭示了光变与光谱相位变化的成因
AI中文摘要：
我们利用 4.1 米 SOAR 望远镜上的 Goodman 高分辨率光谱仪获取的时间序列光谱和多波段测光观测，对 BLG723.31.34651 进行了详细的观测分析，该天体是已报道的第四例充满洛希瓣的热亚矮星食双星成员。我们的光变曲线显示，由潮汐变形的热亚矮星供体引发的周期为 $P=64~{\rm min}$ 的周期性测光变，以及供体被不透明吸积盘的深度食。我们报告了两个光变曲线模型解，二者在 $2\sigma$ 范围内一致，均表明 BLG723.31.34651 包含一个典型的热亚矮星供体、一个白矮星吸积体，以及一个被照射的不透明吸积盘。我们的光谱分析发现，有效温度和表面重力存在统计上显著的相位相关变化，与观测光变曲线中的相位相关变化重合。我们将这些变化归因于供体潮汐变形导致的局地大气参数内在变化，以及吸积盘未建模的光谱流量贡献的共同作用
英文摘要：
We present a detailed observational analysis of BLG723.31.34651, the fourth reported eclipsing member of the class of Roche lobe-filling hot subdwarfs, using time series spectroscopy and multi-band photometric observations from the Goodman High Throughput Spectrograph on the 4.1-m SOAR telescope. Our light curves show periodic photometric variability at $P=64~{\rm min}$ from the tidally-deformed hot subdwarf donor and deep eclipses of the donor by an opaque accretion disc. We report two light curve model solutions that agree with each other to within $2σ$, both suggesting that BLG723.31.34651 contains a typical hot subdwarf donor, a white dwarf accretor, and an irradiated opaque accretion disc. Our spectroscopic analysis identifies statistically significant phase-dependent variations in the effective temperature and surface gravity coinciding with the phase-dependent variations seen in our observed light curves. We attribute these variations to a combination of intrinsic variations in local atmospheric parameters due to tidal deformation of the donor and unmodeled spectroscopic flux contributions from an accretion disc.
