The researchers found that Vesta's normalized mean MOI is about 0.3734. This value is lower than if the asteroid was homogeneous (0.3980). It shows that its inside is denser than its surface material.
Inside Vesta: Learn About the Asteroid’s Hidden Layers Through MOI Analysis
Understanding Vesta’s Internal Structure Through Moment of Inertia – The mean moment of inertia (MOI) helps scientists understand a planet’s inside. Basically, it measures how mass spreads from the center. By knowing MOI, we can test ideas about the planet’s inner layers.
However, it is hard to measure MOI directly for planets or asteroids. Scientists often use models assuming the body is in hydrostatic equilibrium. But Vesta, an asteroid, has an irregular shape. So, this method does not work well for it.
The Dawn spacecraft orbited Vesta for one year. Particularly, it helped collect data to study Vesta’s gravity and rotation precisely. Also, Scientists used this data to measure the gravity field and spin axis motion of Vesta.
Vesta’s Internal Structure
The researchers found that Vesta’s normalized mean MOI is about 0.3734. This value is lower than if the asteroid was homogeneous (0.3980). It shows that its inside is denser than its surface material.
By combining the gravity field and normalized mean MOI data, researchers developed a three-layer internal structure model for Vesta, consisting of a crust, mantle, and core. This model provides a better understanding of Vesta’s radial density distribution.
The effective density spectrum, which is the spectral ratio of the gravity and gravity-from-shape spectral amplitudes, also supports the idea of a differentiated interior for Vesta. The high correlation between the measured gravity and the gravity from shape up to degree 17 allows for the effective density spectrum to be used to independently constrain the radial density structure.
These findings provide valuable insights into the internal structure of Vesta, a key step in understanding the formation and evolution of our solar system.
Closing Remarks
This finding means Vesta likely has a layered interior with a dense core and mantle. Scientists built models with three layers: crust, mantle, and core. Thereafter, they used data to estimate each layer’s size and density using Markov-chain Monte Carlo (MCMC) methods.
The model matched observations by considering how dense each layer must be to fit the data on gravity and shape variation.
The study shows:
- Vesta has a denser interior than surface layers.
- Its core likely does not exceed 150 km in radius.
- The density grows steadily from outer crust to core.
This research helps us better understand small planetary bodies and their formation histories. Learning more about space objects like Vesta can inspire young scientists interested in geology, space exploration, or planetary science careers.
References
Konopliv, A.S., et al. (2025). High-degree gravity field and internal structure of asteroid Vesta from Dawn orbit analysis. Nature Astronomy. https://www.nature.com/articles/s41550-025-02533-7
Additionally, to stay updated with the latest developments in STEM research, visit ENTECH Online. Basically, this is our digital magazine for science, technology, engineering, and mathematics. Furthermore, at ENTECH Online, you’ll find a wealth of information.
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Until 2023, Dr. Charudatta S Pathak held multiple academic positions, including lecturer, assistant professor, professor, dean, principal, director, and vice chancellor at public and private universities across India. From 2008 to 2010, he held the position of project lead in the CAE department at a European multinational corporation. Throughout his 28-year professional experience, he observed a requirement for reliable publications aimed at youngsters in grades 8 to 12, specifically for early-stage career planning. He initiated the establishment of ENTECH Digital Magazine, a complimentary periodical released on a monthly basis, accessible via stemconference.in and magzter.com. Teenagers with a keen interest in Science, Technology, Engineering, and Mathematics (STEM) and aspiring to pursue professional paths in these domains can consider reading ENTECH Digital Magazine.
