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- Creators: School of Earth and Space Exploration
- Creators: Auchterlonie, Lauren
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
- Resource Type: Text
- Status: Published
Stellar mass loss has a high impact on the overall evolution of a star. The amount<br/>of mass lost during a star’s lifetime dictates which remnant will be left behind and how<br/>the circumstellar environment will be affected. Several rates of mass loss have been<br/>proposed for use in stellar evolution codes, yielding discrepant results from codes using<br/>different rates. In this paper, I compare the effect of varying the mass loss rate in the<br/>stellar evolution code TYCHO on the initial-final mass relation. I computed four sets of<br/>models with varying mass loss rates and metallicities. Due to a large number of models<br/>reaching the luminous blue variable stage, only the two lower metallicity groups were<br/>considered. Their mass loss was analyzed using Python. Luminosity, temperature, and<br/>radius were also compared. The initial-final mass relation plots showed that in the 1/10<br/>solar metallicity case, reducing the mass loss rate tended to increase the dependence of final mass on initial mass. The limited nature of these results implies a need for further study into the effects of using different mass loss rates in the code TYCHO.
Tecolote Volcano in the Pinacate Volcanic Field in Mexico contains multiple vents within a horseshoe-shaped crater that have all produced various ejecta (Zawacki et al. 2019). The objectives of this research are to map ballistic distribution to understand the relationship between the source vent or vents and the bombs and ballistics that litter the region around Tecolote, and interpret the eruption conditions that ejected those bombs by using their distributions, morphologies, and fine-scale textures.
The findings of this work are that these bombs are apparently from the last stages of the eruption, succeeding the final lava flows. The interiors and exteriors of the bombs display different cooling rates which can are indicated by the fabric found within. Using this, certain characteristics of the bombs during eruption were extrapolated. The ‘cow pie’ bombs were determined to be the least viscous or contained a higher gas content at the time of eruption. Whereas the ribbon/rope bombs were determined to be the most viscous or contained a lesser gas content. Looking at the Southern Bomb Field site, it is dominated by large bombs that were during flight were molded into aerodynamic shapes. The Eastern Rim site is dominated by smaller bombs that appeared to be more liquid during the eruption. This difference in the two sites is a probable indication of at least two different eruptive events of different degrees of explosivity. Overall, aerodynamic bombs are more common and extend to greater distances from the presumed vent (up to 800 m), while very fluidal bombs are uncommon beyond 500 meters. Fluidal bombs (‘cow pie’, ‘ribbon’, ‘rope/spindle’) show a clear trend in decreasing size with distance from vent, whereas the size-distance trend is less dramatic for the aerodynamic bombs.