CSS J213934.3-050020 (hereafter J213934) was originally found as an EW-type eclipsing binary star with a period of 0.225456 days by Catalina Real-time Transient Survey. With the stellar atmospheric parameters from the LAMOST, it is found that the temperature is much higher than those of normal EW-type binaries and does not follow the period–temperature relation of EW-type eclipsing binary stars. To study the physical properties of the variable star, new B and V light curves were obtained by using the 70 cm telescope at the Lijiang station of Yunnan Observatories. It is detected that this variable star is a high-amplitude δ Scuti-type pulsating star rather than an EW-type eclipsing binary. On the diagram, J213934 lies inside the classical Cepheid instability strip where most δ Scuti stars are located. The results of pulsating frequency analysis show the fundamental frequency f ₀ = 6.8195 day⁻¹, the first overtone f ₁ = 8.8709 day⁻¹ and 4 harmonics or linear combinations. The mass of J213934 is estimated as . The period is revised as 0.11272960 days by using 16 new determined times of light maximum. Meanwhile, it is discovered that its O − C curve shows an upward parabolic variation and a sinusoidal variation. The upward parabolic variation may be a part of a cyclic change or a long-time pulsation period increase caused by its evolution. The sinusoidal variation may be caused by the light-travel-time effect via the presence of a companion star.

CSS J213934.3-050020（以下简称J213934）最初被Catalina Real-time Transient Survey发现为一颗周期为0.225456天的EW型食双星。通过LAMOST的恒星大气参数，发现温度远高于正常EW型双星的温度，并且不遵循EW型食双星的周期温度关系。为研究变星的物理性质，利用云南天文台丽江站的70 cm望远镜获得了新的B和V光变曲线。经检测，这颗变星是一颗高振幅δ Scuti型脉动星，而不是EW型食双星。在图中，J213934位于大多数盾牌δ星所在的经典造父变星不稳定带内。脉动频率分析结果显示基频f ₀ = 6.8195 day ^-1，_一阶泛音f ₁ = 8.8709 day ^-1和4次谐波或线性组合。J213934 的质量估计为。使用 16 个新确定的最大光照时间将周期修正为 0.11272960 天。同时，发现其O - C曲线显示向上抛物线变化和正弦变化。向上抛物线变化可能是其演化引起的周期性变化或长时间脉动周期增加的一部分。正弦变化可能是由伴星存在的光传播时间效应引起的。