Joshua Reding

We report the discovery of short-period photometric variability and modulated Zeeman-split hydrogen emission in SDSSJ125230.93-023417.72 (EPIC 228939929), a variable white dwarf star observed at long cadence in K2 Campaign 10. The behavior is associated with a magnetic (B = 5.0 MG) spot on the stellar surface, making the 317.278-second period a direct measurement of the stellar rotation rate. This object is therefore the fastest-rotating apparently isolated (without a stellar companion) white dwarf yet discovered, and the second found to exhibit chromospheric Balmer emission after GD 356, in which the emission has been attributed to a unipolar inductor mechanism driven by a possible rocky planet. We explore the properties and behavior of this object, and consider whether its evolution may hold implications for white dwarf mergers and their remnants.

The Kepler K2 mission has discovered a significant population of white dwarf stars that exhibit photometric variability due to surface inhomo-geneities likely related to magnetism. These "spot-ted" white dwarfs present not only in temperature regimes where we expect convection to dominate white dwarf photospheres, but also where radiation should dominate. We present an exploration of spotted white dwarfs as a function of various physical characteristics, including temperature , magnetic field strength, and rotational period , in order to better understand the origins of these photometric variations.

This paper seeks to use data from Colgate University’s Foggy Bottom Observatory to confirm an established relationship between the peak luminosities and light curve shapes of type Ia supernovae. Using this relationship, and the peak apparent brightnesses observed at Foggy Bottom Observatory, the distance to SN 1991M in the galaxy IC 1151 will be determined. The process used will be evaluated for success, and will set the standard for future supernova photometry at Colgate.

There is a difficulty which is inherent in photometric analysis of supernovae in that as a supernova fades, it becomes more and more difficult to detect and measure what little light is still being produced from the event. Though it lies at the end of a light curve, this data is still important, and so methods must be considered which will facilitate accurate collection. Standard methods of aperture photometry in the Image Reduction and Analysis Facility (IRAF) involve reading pixel-by-pixel flux measurements across a circular aperture and fitting a curve to define the centroid of this flux, which in turn should designate the center of the object. However, once a supernova is sufficiently faint, this process may fail due to low flux from the supernova, contribtions from the underlying galaxy, and instrumental and sky noise. Therefore, this paper explores the use of a user-defined template as a rigid designator of the centers of objects rather than the result of an automated centroid calculation. This method was tested on SN 1991M in the galaxy IC 1151, and the light curves produced compared to previously
published results.

We undertook spectral analysis of fourteen protoplanetary disks (proplyds) in the Orion Nebula in order to detect the presence of photoevaporation due to the nearby Trapezium stars (Ori A, B, C, and D). The proplyd data was taken using the SpeX spectrograph at the Infrared Telescope Facility (IRTF) on Mauna Kea in Hawaii, which measures in the 0.8 to 5.4 μm range. Using the program SpexTool, we extracted spectra from the images of these proplyds in order to detect molecular hydrogen vibrational emission at wavelengths 2.1218 μm and 2.4066 μm. After subtracting abnormal nebular emissions, we determined the flux of these features using IRAF.  We found that the flux of the hydrogen features in the proplyds exceed those of the nebula, which indicates that photoevaporation is, in fact, taking place in these proplyds.