Scientists are astounded by the extraordinary survival of the planet 8 Ursae Minoris b, which defied the odds by avoiding annihilation from its expanding host star. This remarkable discovery challenges existing knowledge about stellar and planetary evolution, leaving experts puzzled yet fascinated.
Located 520 light years away in the Milky Way, 8 Ursae Minoris b has managed to persist despite the inevitable fate that awaited it. Typically, when a host star expands due to fuel depletion, engulfing any nearby celestial bodies, a planet like 8 Ursae Minoris b would have succumbed to this fate. However, this planet remains intact.
A global team of over 40 researchers, led by Marc Hon from the University of Hawai’i and Dr. Dimitri Veras from the University of Warwick, renowned for their expertise in white dwarf stars, made this intriguing discovery.
Dr. Veras explained, “The distance between our Earth and the Sun is measured as 1 astronomical unit (1 au). Surprisingly, 8 Ursae Minoris b orbits its star at a distance of 0.5 au. While this distance alone is not unusual, what perplexes us is that the star is currently in its dying phase, having already depleted some of its fuel.”
As stars consume their fuel, they expand significantly in size. In this case, the host star had already expanded to 0.7 au, a point where it should have consumed and obliterated the planet. The continued existence of 8 Ursae Minoris b is a puzzling anomaly.
Further investigation by the scientists led to two potential explanations. Dr. Veras elaborated, “The first and more plausible explanation is that the star previously had a companion star, effectively a binary star system, which limited its growth and allowed the planet to survive. Subsequently, the companion star merged with the primary star, giving the appearance of a single star.”
“The second theory, though less explored, involves another binary companion scenario. In this case, the merger of the two stars resulted in the formation of a disk, giving rise to a second-generation planet like 8 Ursae Minoris b.”
This discovery carries broader implications for understanding the evolutionary processes of stars, such as our Sun, and the development of planets within our solar system. It underscores the importance of identifying and studying unusual cases like this one, as rare occurrences often provide profound insights into stellar and planetary physics.
Dr. Veras concluded, “By comprehending these exceptional planetary systems, we gain new perspectives on the evolution of planets and stars, driving us to explore even more extraordinary phenomena.”
Named Halla, the Jupiter-like planet orbits a red giant star named Baekdu at an incredibly close range. Baekdu had previously expanded to a size 1.5 times greater than Halla’s orbital distance, nearing the point of engulfment, before subsequently contracting to its present size. The survival of Halla raises intriguing questions about the evolution of planets, including theories that range from the prevention of complete expansion and engulfment by an original binary star system to the formation of the planet through the gas cloud resulting from a violent stellar collision.
Marc Hon from the University of Hawai’i commented, “Most stars exist in binary systems, but we have yet to fully understand how planets form in such systems. It is reasonable to speculate that many more peculiar planetary systems may exist due to the influence of binary companions.”
Professor Bill Chaplin from the University of Birmingham also added, “This remarkable discovery showcases the meticulous and comprehensive studies made possible by cutting-edge data, including the precise analysis of the host star’s natural oscillations through asteroseismology, as observed by the TESS space telescope. This data unequivocally confirms the star as a core-helium-burning red giant.”
For more details on this groundbreaking discovery, refer to the article “Astronomers Discover a Mysterious Planet That Shouldn’t Exist.”
Reference: “A close-in giant planet escapes engulfment by its star” by Marc Hon, Daniel Huber, Nicholas Z. Rui, Jim Fuller, Dimitri Veras, James S. Kuszlewicz, Oleg Kochukhov, Amalie Stokholm, Jakob Lysgaard Rørsted, Mutlu Yıldız, Zeynep Çelik Orhan, Sibel Örtel, Chen Jiang, Daniel R. Hey, Howard Isaacson, Jingwen Zhang, Mathieu Vrard, Keivan G. Stassun, Benjamin J. Shappee, Jamie Tayar, Zachary R. Claytor, Corey Beard, Timothy R. Bedding, Casey Brinkman, Tiago L. Campante, William J. Chaplin, Ashley Chontos, Steven Giacalone, Rae Holcomb, Andrew W. Howard, Jack Lubin, Mason MacDougall, Benjamin T. Montet, Joseph M. A. Murphy, Joel Ong, Daria Pidhorodetska, Alex S. Polanski, Malena Rice, Dennis Stello, Dakotah Tyler, Judah Van Zandt, and Lauren M. Weiss, 28 June 2023, Nature.
DOI: 10.1038/s41586-023-06029-0
Frequently Asked Questions (FAQs) about Survival
Q: How did the planet 8 Ursae Minoris b survive its host star’s expansion?
A: The survival of planet 8 Ursae Minoris b despite its host star’s expansion is a mystery. Two possible explanations have been proposed by scientists. The first suggests the presence of a binary star system that limited the star’s growth and allowed the planet to survive. The second theory involves a stellar merger that formed a disk from which the planet was generated, making it a second-generation planet. Further research is needed to gain a deeper understanding of this unusual phenomenon.
More about Survival
- Astronomers Discover a Mysterious Planet That Shouldn’t Exist
- Nature: “A close-in giant planet escapes engulfment by its star”
