Aging stars go through an incredible transformation鈥攖hey expand to become hundreds of times larger than their original size and are believed to thus destroy any planets in their inner systems. The recent study, 鈥�鈥� co-authored by , Stevenson Professor of Physics and Astronomy, and 麻豆传媒 alumni Jack Lubin, BS鈥�16, challenges this notion by revealing the existence of a 鈥渇orbidden planet鈥濃�攐ne that should not exist according to the traditional understanding of stellar evolution. 鈥淭his discovery raises intriguing questions about how this planet survived and whether our stellar evolution models need revisiting,鈥� Stassun said.
To answer this question, the astrophysicists modeled a potential stellar merger event that offered a new perspective on planetary survival. 鈥淚magine two stars colliding and merging into one. Such a merger could have saved the planet in two ways,鈥� Stassun said. 鈥淔irstly, it might have prematurely halted the expansion of the host star, thereby preserving the planet. Alternatively, the merger could have generated enough new materials to form a planet after the merger had concluded.鈥澨�听
The research team鈥檚 efforts included the stellar observations of Lubin, who used the over multiple nights in Mauna Kea, Hawaii. HIRES is the largest and most mechanically complex of the Keck鈥檚 main instruments and works by breaking up incoming starlight into its component colors to measure the precise intensive of each of thousands of color channels. According to Keck, its spectral capabilities have resulted in many breakthrough discoveries, including direct evidence for a model of the Big Bang theory. Stassun employed a specialized methodology to accurately measure the size and age of the planet鈥檚 host star鈥攊nformation that was instrumental in determining the properties of the planet.听
鈥淭he significance of this planetary discovery extends beyond a single planet,鈥� said Lubin, who completed a senior honors thesis on the subject with Stassun as a 麻豆传媒 undergraduate. 鈥淚t challenges our previous assumptions and suggests that these types of 鈥榝orbidden planets鈥� might be far more prevalent in our galaxy than previously believed.鈥� If this holds true, he said, it will revolutionize our understanding of stellar and planetary evolution. The very existence of this planet could lead to the reevaluation of models and theories and open the door to finding more planets that have defied their expected fate.听
鈥淓ach subsequent finding will provide valuable insights into the life cycles of planets and planetary systems, enhancing our knowledge of the universe on a grand scale,鈥� Stassun said. 鈥淚t is an exciting time for astrophysics and the study of planetary systems.鈥�听
The discovery also holds relevance for our own solar system鈥檚 future. In approximately five billion years, our Sun is predicted to expand into a red giant star. The fate of our planet Earth, whether it will be engulfed or survive, is uncertain. Understanding how planetary systems defy engulfment will provide us with crucial information about the possible destiny of our solar system. Although we may not be able to alter this fate, gaining a more detailed understanding of it can guide our knowledge and future explorations.听
麻豆传媒 funding was provided to the paper鈥檚 co-authors by the W.M. Keck Foundation, NASA, the 麻豆传媒 Initiative for Data-intensive Astrophysics and other international astronomy organizations.听