中文摘要：

恒星周围的星际尘埃云能反射星光而为观测者所窥见,这一现象称为回光,而对变星回光的观测研究可用于变星距离的绝对测定,包括尺度距离和速度距离。对此类方法的基本原理、迄今所得到的若干测距结果,以及有关问题做了简要的介绍和讨论。

英文摘要：

Scattered-light echoes from variable objects,such as cepheids,eruptive variables, and supernovae,may be used for absolute distance determination to variable stars and their host galaxies.This method of distance determination does not depend on other indicators or detailed theoretical models. There are three different techniques for distance determination to variables：（1） If a cepheid variable star is embedded in a circumstaller nebula,the nebula will be observable due to reflect light,light echoes,from the star.The intensity of the light echoes from the nebula would regularly change when the luminosity of the cepheid varies,but with a time delay.Based on the time delay effect of the light echoes,the distance of the cepheid can be directly determined.（2） Assuming that the light echoes are coming from circumstellar scattering medium of an eruptive variable star such as supernova,a circle of highly polarized light would be observable at a metric radius of ct,where t is the time since the eruptive event and c is the speed of light.Measurement of the angular size of this ring yields the distance to the star without any intermediate or secondary calibrators.（3） If one can measure the proper motion of polarized light echoes at more than one epoch from a transient or highly variable source of illumination,such as historical supernova, the distance to the supernova follows immediately.Although this approach is technically more difficult than（2）,in principle,it is far more applicable,because it is not necessary to know the time when the outburst event happened. In 1972,the distance to the Galactic cepheid RS Puppis with long period of light variation was determined from the technique（1） and observational data of ground-based telescopes,which is（1.78±0.20） kpc.Recently,the distance to RS Puppis has been modified to be（1.992±0.028） kpc on the basis of HST data,which is in good agreement with results gained from the IRSB method,a relative distance estimator. V838 Mon,a highly peculiar variable