Complex sentence: Yet its mass and blue color indicate that it had burned only for 20 million years, which led to the explanation that it was part of a triple-star system consisting of two closely bound stars and one outer star.
Split into simpler sentences: Yet its mass and blue color indicate that it had burned only for 20 million years. Which led to the explanation that it was part of a triple-star system consisting of two closely bound stars and one outer star.