Red Giant Brightness Variations Still Mysterious

As the get older, Sun-like stars become red giants. 30-50 percent of these red giants exhibit a strange variability in their brightness that has so far eluded explanation. Image Credit: ESO/S. Steinhofel

Like everything else in the Universe, stars get old. As they become older, stars like our own Sun "puff up", becoming red giants for a period before finally settling down into white dwarfs. During this late period of their stellar lives, about 30% of low-mass red giants exhibit a curious variability in their brightness that remains unexplained to this day. A new survey of these types of red giants rules out most of the current explanations put forth, making it necessary to find a new theory for their behavior.(...)
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هفت آسمان سه‌شنبه 17 آذر‌ماه سال 1388 ساعت 07:42 ب.ظ