The construction of the James Webb Space Telescope has brought attention to infrared astronomy and cosmology. The potential information about our universe to be gained by this mission and future infrared telescopes is staggering, but infrared observation faces many obstacles. These telescopes face large amounts of noise by many phenomena, from emission off of the mirrors to the cosmic infrared background. Infrared telescopes need to be designed in such a way that noise is minimized to achieve sufficient signal to noise ratio on high redshift objects. We will investigate current and planned space and ground based telescopes, model the noise they encounter, and discover their limitations. The ultimate goal of our investigation is to compare the sensitivity of these missions in the near and mid IR and to propose new missions. Our investigation is broken down into four major sections: current missions, noise, signal, and proposed missions. In the proposed missions section we investigate historical and current infrared telescopes with attention given to their location and properties. The noise section discusses the noise that an infrared telescope will encounter and set the background limit. The signal section will look at the spectral energy distributions (SED) of a few significant objects in our universe. We will calculate the intensity of the objects at various points on Earth and in orbit. In the final section we use our findings in the signal and noise sections to model integration times (observation time) for a variety of missions to achieve a given signal to noise ratio (SNR).

RR Lyrae stars are old, iron-poor, Helium-burning variable stars. RR Lyraes are extremely useful for tracing phase-space structures and metallicities within the galaxy because they are easy to identify, have consistent luminosities, and are found in large numbers in the galactic disk, bulge, and halo. Here we present a new set of spectroscopic metallicity calibrations that use the equivalent widths of the Ca II K, Hγ, and Hδ lines to calculate metallicity values. Applied to spectroscopic survey data, these calibrations will help shed light on the evolution of the Milky Way and other galaxies.

26Al(p,p)26Al and 26Al(p,p’)26Al* scattering reactions were performed at the Holifield Radioactive Ion Beam Facility (HRIBF) at the Oak Ridge National Laboratory (ORNL). The purpose of the elastic scattering study was to determine properties of previously uncharacterized 27Si levels above the proton threshold in the energy range E(c.m.) ~ 0.5 - 1.5 MeV and to calculate reaction rates for the 26Al(p,γ[gamma])27Si reaction that destroys 26Al. The inelastic scattering reaction was also evaluated to investigate the reaction that produces the metastable state of 26Al at E(c.m.) = 228 keV, which would in turn destroy 26Al in the stellar environment. Pure 26Al beams (E(beam) = 13 - 41 MeV) with intensities of ~2*106 26Al/s bombarded a thin polypropylene target of 46 μ[micro]g/cm2 thickness for 7 days. Scattered protons were detected in the Silicon Detector Array (SIDAR), covering laboratory angles 18 to 41 degrees. Background events were rejected by detecting these protons in coincidence with recoiled 26Al particles in an ionization chamber, and proton yields were measured at 45 energies from E(c.m.) = 0.49 - 1.53 MeV. A thick 2.4 mg/cm2 polypropylene target was also bombarded with a 32 MeV 26Al beam for 1.5 days for comparison with thin-target excitation functions. Little evidence for the inelastic scattering reaction was observed, indicating that this is not a significant destruction pathway. For the first time, however, an upper limit for the cross section of this reaction was estimated, and it has been set at 5*10-2 barns. The first upper limits were also established for possible resonances of the elastic scattering reaction with angular momentum transfers up to L = 3 that were not directly observed by this study. Thin-target elastic scattering data suggested a potential resonance at E(r) = 544 keV, which had not been previously observed, with (9/2, 11/2)+ spin and proton width Γp[Gamma_p] ≤ 1 keV. Thick-target analysis appeared to confirm this result. An upper limit for the strength of this resonance was estimated to be 1.4*10-5 keV or 1.6*10-5 keV for a 9/2+ or 11/2+ state, respectively, moderately increasing the total 26Al(p,γ[gamma])27Si resonant reaction rate at supernova temperatures.

This thesis explores the topic of maximum mass stability of neutron stars. The outer structure is detailed and explores nuclear pasta phases, the neutron drip line, and density transitions of matter in the crust and atmosphere layers. Other discussion points include superfluids in the crust and core, vortex roles in neutron stars, and magnetic field effects on the EOS in neutron stars. The inner core is studied in much more detail due to its significant role in EOS. The variety of stars include pion condensate stars, kaon condensate stars, npeu stars, npeu stars with the inclusion of hyperons, quark-hybrid stars, and strange stars. Included with these is a description of nucleon-nucleon, nucleon-nucleon-nucleon interactions, the appearance factors that affect hyperon species, and the formation process of kaons, pions, quarks, and hyperons. The ending EOS are compared with their maximum mass values to determine which ones are likely to limit the mass of neutron stars.

Beta Lyrae is a complex binary star system with a 13-day orbital period containing two massive stars that are in the process of mass reversal accretion. The primary star is the higher mass star which is gaining mass from the secondary star. This reversal mass accretion causes gas to build and form a disk around the primary star. The disk is geometrically and optically thick. Previous interferometric studies in Optical and Infrared wavelengths have shown that a bipolar jet exists in the system and suggest that the jet contributes to the H-alpha emission. Meanwhile, other studies have suggested that the disk contributes to the H-alpha emission. We have taken into account various factors to model the emission of H-alpha from Beta Lyrae. The observed profile is double-peaked and varies with orbital phase. We found that the jet produces a single-peak for H-alpha emission. Meanwhile, the disk produces a double-peak for H-alpha emission if it is based on Keplerian motion. We use our model to interpret the observed H-alpha emission variations in the line shape with orbital phase.

Observing the dynamic interaction between stars and their close stellar neighbors is key to establishing the stars’ orbits, masses, and other properties. Our ability to visually discriminate nearby stars is limited by the power of our telescopes, posing a challenge to astronomers at small observatories that contribute to binary star surveys. Masks placed at the telescope aperture promise to augment the resolving power of telescopes of all sizes, but many of these masks must be manually and repetitively reoriented about the optical axis to achieve their full benefits. This paper introduces a design concept for a mask rotation mechanism that can be adapted to telescopes of different types and proportions, focusing on an implementation for a Celestron C11 Schmidt–Cassegrain optical tube assembly. Mask concepts were first evaluated using diffraction simulation programs, later manufactured, and finally tested on close double stars using a C11. An electronic rotation mechanism was designed, produced, and evaluated. Results show that applying a properly shaped and oriented mask to a C11 enhances contrast in images of double star systems relative to images captured with the unmasked telescope, and they show that the rotation mechanism accurately and repeatably places masks at target orientations with minimal manual effort. Detail drawings of the mask rotation mechanism and code for the software interface are included.

We present preliminary analysis of mid-infrared spectra of M-type and C-type Mira variables. Due to the brightness of this sample, it is straightforward to monitor changes with phase in the infrared spectral features of these regular pulsators. We have spectra of 25 Mira variables, taken with phase, using the Spitzer Infrared Spectrograph (IRS) high-resolution module. Each star has multiple spectra obtained over a one-year period from 2008-09. This is a rich, unique data set due to multiple observations of each star and the high signal-to-noise ratio from quick exposure times to prevent saturation of the IRS instrument. This paper focuses on the 17.6 and 33.2 micron lines shared by M-types and C-types. These are mostly emission lines that change with phase. We discuss preliminary physical diagnostics for the atmospheres based on the lines, as well as possible line identifcations such as fuorescence of metal species.

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The quality and quantity of polarimetric data being collected for stellar sources creates new opportunities for studying stellar properties and evolution, and also leads to new challenges for modeling and interpreting such data. Inspired by fresh prospects for detecting the Hanle effect to study photospheric magnetic fields, we have focused attention on purely geometrical aspects for polarimetric variability in the example of oblique magnetic rotators. In the case of axisymmetric fields, we highlight two key facts: (a) polarimetric lightcurves necessarily exhibit a certain time symmetry with rotation phase, and (b) variations in the polarization position angle can be modeled based on geometrical projection effects, independent of the photospheric magnetic field. These conclusions also have general applicability, such as to Thomson scattering and the transverse Zeeman effect. The authors gratefully acknowledge that funding for this work was provided by the National Science Foundation, grant AST-0807664.