Astrophysicists from the California Institute of Technology, the MIT Kavli Institute for Astrophysics and Space Research, and the University of Amsterdam have made a remarkable discovery, uncovering a binary system named ZTF J2020+5033. What makes this finding intriguing is that it consists of two stars—one being a brown dwarf and the other a red dwarf—that are exceptionally small and close together, fitting comfortably within the size of the Sun. The system, located approximately 457 light-years from Earth, is considered remarkably close in astronomical terms.
Through data gathered from the Zwicky Transient Facility, the research team found that the two stars orbit each other for an astounding period of just 1.9 hours. This tight orbit sets a new record for the closest-ever recorded orbit of a brown dwarf. Brown dwarfs are peculiar celestial objects, lying between planets and stars in size and characteristics. While they possess cores capable of initiating fusion, it is not hydrogen-based, causing them to emit faint light, making them challenging to study.
The red dwarf in the ZTF J2020+5033 system displayed unique attributes, being comparatively small, with a radius of only 17.6% of the Sun and a mass of 13.4%. On the other hand, the brown dwarf appeared larger for its category, with a mass 80.1 times that of Jupiter and a radius similar to the gas giant’s. Moreover, the research team’s analysis suggested that the binary system is quite old, indicating that both stars were once much larger and orbited each other at a greater distance. As time progresses, the stars will continue to draw closer, with the brown dwarf eventually drawing material from its smaller companion due to its higher surface gravity.
This groundbreaking discovery provides a rare opportunity to gain insights into the nature of brown and red dwarfs, unraveling the mysteries of these intriguing celestial objects and offering valuable clues about the formation and evolution of such binary systems. The astrophysicists involved plan to investigate the ZTF J2020+5033 system further, seeking to deepen our understanding of these enigmatic stars and shed light on the factors that led to the existence of this fascinating binary system.
The novel research is, at the time of publishing, available for preprint on arXiv.
References
- El-Badry, K., Burdge, K. B., van Roestel, J., & Rodriguez, A. C. (2023). A transiting brown dwarf in a 2 hour orbit. arXiv. https://doi.org/10.48550/arXiv.2307.15729
- Yirka, B. & Phys.org. (2023, August 3). Binary system discovered with two stars so close together they could fit inside the sun. Phys.Org. https://phys.org/news/2023-08-binary-stars-sun.html
