Data-driven models of stellar spectra are useful tools to study non-stellar information, such as the Diffuse Interstellar Bands (DIBs) caused by intervening interstellar material. Using $\sim 55000$ spectra of $\sim 17000$ red clump stars from the APOGEE DR16 dataset, we create 2nd order polynomial models of the continuum-normalized flux as a function of stellar parameters ($T_{eff}$, $\log g$, [Fe/H], [$\alpha$/Fe], and Age). The model and data show good agreement within uncertainties across the APOGEE wavelength range, although many regions reveal residuals that are not in the stellar rest-frame. We show that many of these residual features -- having average extrema at the level of $\sim3\%$ in stellar flux on average -- can be attributed to incompletely-removed spectral lines from the Earth's atmosphere and DIBs from the interstellar medium (ISM). After removing most of the remaining contamination from the Earth's sky, we identify 84 absorption features not seen in unreddened sightlights that have $<50\%$ probability of being noise artifacts -- with 25 of these features having $<5\%$ probability of being noise artifacts -- including all 10 previously-known DIBs in the APOGEE wavelength range. Because many of these features occur in the wavelength windows that APOGEE uses to measure chemical abundances, characterization and removal of this non-stellar contamination is an important step in reaching the precision required for chemical tagging experiments. Proper characterization of these features will benefit Galactic ISM science and the currently-ongoing Milky Way Mapper program of SDSS-V, which relies on the APOGEE spectrograph.

翻译：数据驱动的恒星光谱模型是研究非恒星信息（如星际介质造成的弥散星际带）的有效工具。利用APOGEE DR16数据集中约17000颗红团簇星的约55000条光谱，我们构建了连续谱归一化通量关于恒星参数（有效温度、表面重力、金属丰度、α元素丰度和年龄）的二次多项式模型。该模型与数据在APOGEE波长范围内的不确定度内吻合良好，但许多区域呈现出非恒星静止参考系中的残差。研究表明，这些平均极值约为恒星通量3%的残差特征，可归因于地球大气未完全去除的谱线以及星际介质的弥散星际带。在移除大部分残留的天空污染后，我们识别出84个在未红化视线中未见且噪声伪影概率低于50%的吸收特征——其中25个特征的噪声伪影概率低于5%，包含APOGEE波长范围内所有10个已知的弥散星际带。由于这些特征多出现在APOGEE测量化学丰度的波长窗口内，表征并移除此类非恒星污染对于实现化学标记实验所需精度至关重要。对这些特征的准确表征将惠及银河系星际介质科学研究，以及当前正在进行的基于APOGEE光谱仪的SDSS-V银河系制图计划。