Matching Items (3)
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- All Subjects: Exoplanets
- Creators: Patience, Jennifer
Description
As the detection of planets become commonplace around our neighboring stars, scientists can now begin exploring their possible properties and habitability. Using statistical analysis I determine a true range of elemental compositions amongst local stars and how this variation could affect possible planetary systems. Through calculating and analyzing the variation in elemental abundances of nearby stars, the actual range in stellar abundances can be determined using statistical methods. This research emphasizes the diversity of stellar elemental abundances and how that could affect the environment from which planets form. An intrinsic variation has been found to exist for almost all of the elements studied by most abundance-finding groups. Specifically, this research determines abundances for a set of 458 F, G, and K stars from spectroscopic planet hunting surveys for 27 elements, including: C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ba, La, Ce, Nd, Eu, and Hf. Abundances of the elements in many known exosolar planet host stars are calculated for the purpose investigating new ways to visualize how stellar abundances could affect planetary systems, planetary formation, and mineralogy. I explore the Mg/Si and C/O ratios as well as place these abundances on ternary diagrams with Fe. Lastly, I emphasize the unusual stellar abundance of τ Ceti. τ Ceti is measured to have 5 planets of Super-Earth masses orbiting in near habitable zone distances. Spectroscopic analysis finds that the Mg/Si ratio is extremely high (~2) for this star, which could lead to alterations in planetary properties. τ Ceti's low metallicity and oxygen abundance account for a change in the location of the traditional habitable zone, which helps clarify a new definition of habitable planets.
ContributorsPagano, Michael (Author) / Young, Patrick (Thesis advisor) / Shim, Sang-Heon (Committee member) / Patience, Jennifer (Committee member) / Desch, Steven (Committee member) / Anbar, Ariel (Committee member) / Arizona State University (Publisher)
Created2014
Description
How do we visualize environments outside our solar system? I have researched two very alien planets and their compositions with the goal of finding out how those differences would affect the way a planet appears on its surface. The first is a planet orbiting the nearby G type star Tau Ceti. This star has Mg/Si ratio of 1.78, compared to 1.2 found on the Earth. A planet formed around this star could have a very active surface, covered in volcanoes. The other planet is a hypothetical carbon planet that could orbit the star HD 144899. This star has a C/O ratio of 0.8, compared to 0.5 in the Sun. A planet formed here might be comprised mostly of carbides, with a hydrocarbon atmosphere. It would likely be geologically dead, the main forces shaping its surface being meteorites. Both planets, due to their extremes, would likely be barren and lifeless. The results of this project are two digital paintings showcasing my vision of these planets.
ContributorsGonzales, Joshua Michael (Author) / Young, Patrick (Thesis director) / Patience, Jennifer (Committee member) / Button, Melissa (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Art (Contributor)
Created2015-05
Description
Direct imaging is a powerful tool in revealing the architectures of young planetary systems, clearly showing the structure of circumstellar disks. Circumstellar disks, similar to the asteroid belt, are critical elements of any planetary system, and the study of them is important to understanding planet formation. Disks around several main sequence stars have already been observed directly interacting with exoplanets in their respective systems. Imaging can help answer many of the key questions of how disks interact in their respective systems. The Gemini Planet Imager is a high contrast imaging instrument that has spatially resolved several circumstellar disks for the first time, many exhibiting tracers of ongoing planet formation or the presence of a perturbing exoplanet. With this new sample, population analyses of characteristics of disks can now be explored and compared to information at other wavelengths. Direct imaging is also a uniquely accessible tool in engaging students and the community in astronomy. In combination with a course-based undergraduate research experience, direct imaging has the ability to engage students in the process of doing research in a very accessible manner. In Chapter 1, I introduce the concepts related to circumstellar debris disks, further focusing on the sub-field of direct imaging and its value in understanding these systems and engaging students in astronomy. In Chapter 2, I present four images of newly-resolved debris disks in the Scorpius-Centaurus association, comparing their characteristics with many other spatially-resolved circumstellar disks within the moving group. In Chapter 3, I present a uniform analysis of debris disk structure using a consistent and empirically-informed modeling approach. In Chapter 4, I present my findings and experiences in developing and teaching a course-based undergraduate research experience for students in the country’s first online astronomy degree program centered on the direct imaging of brown dwarfs. In Chapter 5, I present my conclusions on the topics I have investigated and discuss future work within the field of direct imaging and its role in driving astronomy research and education forward.
ContributorsHom, Justin (Author) / Patience, Jennifer (Thesis advisor) / Knierman, Karen (Committee member) / Scowen, Paul (Committee member) / Simon, Molly (Committee member) / Young, Patrick (Committee member) / Arizona State University (Publisher)
Created2023