标题： MACHO银河晕数据库中发现五颗新的R Coronae Borealis星 显示英文标题

标题： Discovery of Five New R Coronae Borealis Stars in the MACHO Galactic Bulge Database

摘要： 我们利用MACHO项目光度数据库在银河系核球中发现了五颗新的R Coronae Borealis (RCB)恒星，使已知的银河系RCB恒星总数达到约40颗。 我们获得了光谱以确认这些发现。 新发现的五颗RCB恒星中有四颗是“冷”的（T(eff) < 6000 K），而不是“暖”的（T(eff) > 6000 K），这表明现有样本中暖RCB恒星占多数可能是一种选择偏差。 这些冷RCB恒星比它们的暖型更红且更暗，可能在使用蓝色底片进行的调查中被遗漏了。 根据在MACHO核球区域发现的新RCB恒星数量，可能有约250颗RCB恒星存在于朝向核球的红化“排除”区域中。 显示英文摘要

摘要： We have identified five new R Coronae Borealis (RCB) stars in the Galactic bulge using the MACHO Project photometry database, raising the total number of known Galactic RCB stars to about 40. We have obtained spectra to confirm the identifications. The fact that four out of the five newly identified RCB stars are ``cool'' (T(eff) < 6000 K) rather than ``warm'' (T(eff) > 6000 K) suggests that the preponderance of warm RCB stars among the existing sample is a selection bias. These cool RCB stars are redder and fainter than their warm counterparts and may have been missed in surveys done with blue plates. Based on the number of new RCB stars discovered in the MACHO bulge fields, there may be ~250 RCB stars in the reddened "exclusion" zone toward the bulge.