Between 2015 September and 2016 January, we obtained 18 spectra of the 2015 classical outburst of AG Pegasi—a symbiotic star consisting of a white dwarf (WD), red giant, and surrounding nebula. Modelling the flux contributions of these components reveals that nebular emission, from the reprocessing of high energy WD photons, dominates the 3200–6300 Å range. Nebular emission rises and falls in line with changes seen in the WD, whose properties have been derived using Hβ and He ii (4686 A) line flux, and emission measure calculations. WD parameters follow changes seen in visual band light curves. During the second peak of the outburst, WD temperatures reach 166,000 6000 K, with a luminosity and radius of 14,000 2000 L _⊙ and 0.149 0.014 R _⊙ respectively. These features are consistent with an expansion of the WD pseudo-photosphere due to an accretion rate exceeding that required for stable hydrogen burning.

在 2015 年 9 月至 2016 年 1 月期间，我们获得了 2015 年飞马座 AG 经典爆发的 18 个光谱，这是一颗由白矮星 (WD)、红巨星和周围星云组成的共生星。对这些组分的通量贡献进行建模表明，来自高能 WD 光子再处理的星云发射在 3200-6300 Å 范围内占主导地位。星云发射随 WD 的变化而上升和下降，WD 的特性是使用 H β和 He  ii (4686 A) 线通量和发射测量计算得出的。WD 参数跟随可见带光曲线的变化。在第二次爆发高峰期，WD温度达到166,000 6000 K，光度和半径分别为14,000 2000  L⊙和 _0.149 0.014 R _⊙分别。这些特征与 WD 伪光球层的膨胀是一致的，因为吸积率超过了稳定氢燃烧所需的速度。