近年来随着红外探测技术和红外空间天文的发展，红外波段消光规律的研究取得了突破性进展。IRAS 巡天的一项成果，红外低分辨率光谱表（LRS ）提供了大量有用的中红外光谱数据。对其中的一类S 星，其光谱类型接近来自恒星光球的Ravleigh-Jeans 尾，这类源无明显物质损失，属于光谱型早于MS 型的恒星。该类源的包层并不明显，消光的影响主要来自星际尘埃和星际介质，将Rayleigh-Jeans曲线作为该类源的内禀能谱分布，将LRS 的光谱同标准能谱进行对比，得到的差值便是消光。LRS 的观测结果包含了银经各个方向上从8-22 μm的一段连续光谱，对每一条S型的光谱都与Raxleigh-Jeans 谱进行比对，便可得到不同视线方向上的连续的消光曲线。

In virtue of the evolution of the technique at infrared detection and the infrared space astronomy , infrared extinction law has got great advancement . The Low Resolution Spectra ( LRS ) of the Infrared Astronomy Satellite survey provided us a lot of reliable data in mid-infrared wavelength.S stars are one class of the source whose spectras are similar to the Rayleigh-Jeans curve.They are usuaily stars with spectral types earlier than M5 without substantial mass loss.Because of the unconspicuous circumstellar envelopes extinction is primary due to the inierstellar dust and interste1lar medium.Define the Rayleigh-Jeans curve as the standard spectra of the S stars . Compare the spectra and the Rayleigh-Jeans curve and the contrast is the extinction . There are continuous spectras which from 8μm to 22μm on different directions . Comparing every spectra of the S stars with the Rayleigh-jeans curve , continuous extinction curve on different line of sight will be obtained .