In a stunning cosmic spectacle, an exoplanet situated 950 light years away from Earth is dramatically shedding its atmosphere, creating a gaseous tail that dwarfs even the largest planet in our solar system, Jupiter. The planet, known as HAT-P-32 b, is a "hot Jupiter" – a gas giant that orbits perilously close to its parent star, enduring searing radiation that causes its atmosphere to evaporate, resulting in a tail that’s a staggering 18 times larger than Jupiter. This phenomenon has allowed astronomers to witness one of the largest planetary structures outside our solar system.
The study of HAT-P-32 b, conducted by a team of researchers from The University of California Santa Cruz, offers vital insights into planetary evolution and could potentially solve the mystery of a peculiar absence in the exoplanet catalog. By observing the rate at which this hot Jupiter is losing its atmosphere, scientists are hoping to understand why there is a noticeable lack of intermediate-sized planets, referred to as "hot-Neptunes", orbiting close to their parent stars. This surprising void in our knowledge of exoplanets has been dubbed the "hot-Neptunian desert", and the ongoing atmospheric loss of HAT-P-32 b might just hold the key to unravelling this cosmic conundrum.
A Glimpse into the Cosmic Dance: The Case of HAT-P-32 b
A Planet’s Spectacular Escape
Located a staggering 950 light years from Earth, the exoplanet HAT-P-32 b is putting on quite the display. The planet is dramatically shedding its atmosphere, creating a tail of gas that measures an astonishing 18 times the size of Jupiter. This makes the gaseous tail one of the most colossal planetary structures observed outside our solar system.
HAT-P-32 b is a hefty celestial body, with a mass approximately 68% of Jupiter’s, yet it’s twice as wide. This exoplanet orbits just 3.2 million miles from its host star, making it a mere 3% of the Earth-Sun distance. Completing its orbit every 2.2 days, the gas giant is sizzled by the radiation from its parent star, categorizing it as a ‘hot Jupiter’.
The Extravagant Tail
The extravagant tail trailing HAT-P-32 b is composed of helium gas that’s escaping from its atmosphere. Its discovery came from careful monitoring using telescopes stationed on Earth, including the Hobby-Eberly Telescope of The University of Texas at Austin’s McDonald Observatory. Dr. Zhoujian Zhang, the lead author of the study and a postdoctoral fellow at the University of California Santa Cruz, highlights the sheer size of the gas tail, which he says is about 53 times the planet’s radius.
Bridging the Gap in Exoplanet Catalog
The study of HAT-P-32 b’s atmospheric loss could provide a valuable insight into planetary evolution and solve a puzzling absence of a specific type of planet in our exoplanet catalog. Since the first discovery of exoplanets in the 1990s, more than 5,000 worlds of various shapes, masses, and characteristics have been found. But there seems to be a glaring absence of intermediate-sized planets orbiting close to their stars, often referred to as ‘hot-Neptunes’.
These missing hot-Neptunes could be explained by planets close to their stars losing their atmospheres due to intense radiation. Dr. Zhang notes that capturing planets in the process of losing their atmosphere, like HAT-P-32 b, can help us understand the mechanisms and rate at which these planets lose their mass.
Uncovering the Secrets with Supercomputers
To get a more in-depth understanding of HAT-P-32 b, researchers turned to a 3D simulation using Stampede2 supercomputer of the Texas Advanced Computing Center (TACC). The simulation modeled the interaction between the outflow of gas from the planet and stellar winds from its parent star, revealing that the planetary outflow was both trailing and leading HAT-P-32 b in its orbital path.
The team found that it would take approximately 40 billion years for HAT-P-32 b to lose its entire atmosphere. However, given the lifespan of its parent star, HAT-P-32 A, which is between 2-4 billion years, the planet is unlikely to survive that long. Once the parent star exhausts its hydrogen fuel, it will swell into a red giant, likely engulfing the exoplanet and its remaining atmosphere.
The team plans to study more planets similar to HAT-P-32 b and develop sophisticated simulations for exoplanet dynamics. "We need the computers to make real predictions based on recent advances in the theory and to explain the data. Supercomputers bridge the model and the data," concludes Dr. Zhang.
The study of HAT-P-32 b not only provides a fascinating insight into the dramatic processes occurring in the universe but also holds significant implications for the understanding of planetary evolution. As technology advances and computational power increases, our ability to simulate and understand these distant worlds will only improve, potentially solving some of the most intriguing mysteries in the cosmos.