标题： 造父变星的光度是否受第二参数效应的影响？ 显示英文标题

标题： Are the Luminosities of RR Lyrae Stars Affected by Second Parameter Effects?

摘要： 从造父变星周光关系得出的麦哲伦云（LMC）距离与利用银河系RR lyrae变星亮度刻度得出的距离之间存在严重差异。 有人建议，这个问题可能是由于次参数效应使得将银河系刻度应用于麦哲伦云中的RR lyrae变星不合适，即Mv(RR)可能依赖于[Fe/H]和一个或多个次参数。 显示英文摘要

摘要： There is a serious discrepancy between the distance to the LMC derived from the Cepheid Period-Luminosity relation and that obtained by using the Galactic calibration for the luminosity of RR Lyrae stars. It is suggested that this problem might be due to the fact that second parameter effects make it inappropriate to apply Galactic calibrations to RR Lyrae variables in the Magellanic Clouds, i.e. Mv(RR) could depend on both [Fe/H] and on one or more second parameters.