Interdisciplinary Spectroscopy: The Detection and Characterization of Solar CMEs, Stellar CMEs, and Exoplanets
CitationWilson, Maurice. 2022. Interdisciplinary Spectroscopy: The Detection and Characterization of Solar CMEs, Stellar CMEs, and Exoplanets. Doctoral dissertation, Harvard University Graduate School of Arts and Sciences.
AbstractIn the field of Astrophysics, spectroscopic instruments have become a foundational component of the observers' toolkit when studying starlight. The fundamental principles of spectroscopy can be applied ubiquitously throughout all subfields of Astrophysics. For the study of solar coronal mass ejections (CMEs), we use ultraviolet spectroscopic measurements to determine the plasma diagnostics for a CME. For the study of stellar CMEs, we make predictions for the feasibility of detecting CME-specific signatures from distant stars. For the study of exoplanets, we determine the degree of instrumental broadening in the optical spectral lines detected by a ground-based spectrograph that reveals exoplanet-induced Doppler shifts from bright stars. Within this breadth of research topics, the common denominator is our application of robust spectroscopic techniques to precisely detect a specific signal or precisely determine the characteristics of an astrophysical object of interest. Specifically, our exoplanet analysis focuses on the commissioning of an exoplanet observatory's spectrograph. We determine the stability of the fiber-fed KiwiSpec spectrograph belonging to the MINiature Exoplanet Radial Velocity Array (MINERVA). The instruments' stable conditions allow us to find the spectrograph's systematic noise floor. Our solar CME analysis makes use of a unique archival dataset from the Ultraviolet Coronagraph Spectrometer (UVCS) instrument on the Solar and Heliospheric Observatory (SOHO) spacecraft. The spectra from UVCS derived from the emission of the CME's prominence core plasma as it was observed at two heights in the corona. We use the spectra at both heights to constrain our modelling of the plasma's physical conditions, and thus, determine the energy budget as well as the rate of heating within the CME core. Our stellar CME analysis capitalizes off of the results of our solar CME analysis. Based on a few solar CMEs that have well-defined plasma diagnostics, we use the solar CME properties to estimate the brightness of its spectroscopic signal as if it belongs to a distant star system. We emphasize that three ultraviolet emission lines in particular would most likely be sufficiently bright to detect and would improve the credibility of interpreting the spectroscopic signatures as belonging to a stellar CME. We also suggest that the search for undeniably detected stellar CMEs should work in tandem with exoplanet surveys.
Citable link to this pagehttps://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37371931
- FAS Theses and Dissertations