Physical Sciences and Mathematics Commons^™

High-Resolution Near-Infrared Spectroscopy Of Hd 100546. I. Analysis Of Asymmetric Ro-Vibrational Oh Emission Lines, Joseph Liskowsky, Sean D. Brittain, Joan R. Najita, John S. Carr, Greg W. Doppman, Matthew R. Troutman

Publications

We present observations of ro-vibrational OH and CO emission from the Herbig Be star HD 100546. The emission from both molecules arises from the inner region of the disk extending from approximately 13 AU from the central star. The velocity profiles of the OH lines are narrower than the velocity profile of the [O i] λ6300 line, indicating that the OH in the disk is not cospatial with the Oi. This suggests that the inner optically thin region of the disk is largely devoid of molecular gas. Unlike the ro-vibrational CO emission lines, the OH lines are highly asymmetric. We …

High-Resolution Near-Infrared Spectroscopy Of Hd 100546. Ii. Analysis Of Variable Rovibrational Co Emission Lines, Sean D. Brittain, Joan Najita, John S. Carr, Joseph Liskowsky, Matthew R. Troutman, Greg W. Doppmann

Publications

We present observations of rovibrational CO in HD 100546 from four epochs spanning 2003 January through 2010 December. We show that the equivalent widths of the CO lines vary during this time period with the v = 1–0 CO lines brightening more than the UV fluoresced lines from the higher vibrational states.While the spectroastrometric signal of the hot band lines remains constant during this period, the spectroastrometric signal of the v = 1–0 lines varies substantially. At all epochs, the spectroastrometric signals of the UV fluoresced lines are consistent with the signal one would expect from gas in an axisymmetric …

Molecular Gas In The Circumstellar Environment Of Unusual Evolved Stars, Sarah E. Malek

Electronic Thesis and Dissertation Repository

As low- and intermediate mass stars (with masses up to 8-9 solar masses) age, they experience a series of evolutionary changes which culminate in the removal of nearly their entire envelope through extensive mass loss. The ejected material cools down, which allows for the formation of molecules and the nucleation of dust grains in the circumstellar environment (CSE) of the star. Much about the properties and composition of the gas and dust in these CSEs is not well understood.

Here, we study the rich CSEs of two unusual evolved stars by analyzing spectral observations in the infrared and using molecular …

The Continuum Linear Polarization Signature Of Classical Be Stars, Robbie J. Halonen

Electronic Thesis and Dissertation Repository

Classical Be stars are rapidly-rotating, massive stars that exhibit distinct observational characteristics due to the presence of enveloping, equatorial disks of gas. While diligent observation of these objects has established a reliable description of their geometric and kinematic properties, our understanding of classical Be stars remains distressingly limited on the dynamical front. Principally, we lack a satisfactory characterization of the physical process(es) through which the gaseous disks form and dissipate. In order to understand the mechanisms that govern the development of these enigmatic stars, we use computational codes to produce theoretical models of these objects and their environments. We compare …

Accretion Variability Of Herbig Ae/Be Stars Observed By X-Shooter Hd 31648 And Hd 163296, I Mendigutia, Sean D. Brittain, C Eiroa, G Meeus, B Montesinos, A Mora, J Muzerolle, R D. Oudmaijer, E Rigliaco

Publications

This work presents X-Shooter/Very Large Telescope spectra of the prototypical, isolated Herbig Ae stars HD 31648 (MWC 480) and HD 163296 over five epochs separated by timescales ranging from days to months. Each spectrum spans over a wide wavelength range covering from 310 to 2475 nm. We have monitored the continuum excess in the Balmer region of the spectra and the luminosity of 12 ultraviolet, optical, and near-infrared spectral lines that are commonly used as accretion tracers for T Tauri stars. The observed strengths of the Balmer excesses have been reproduced from a magnetospheric accretion shock model, providing a mean …

Using Photometry To Probe The Circumstellar Environment Of Δ Scorpii, Carol E. Jones, Paul A. Wiegert, Christopher Tycner, Gregory W. Henry, Richard P. Cyr, Robbie J. Halonen, Matthew W. Muterspaugh

Information Systems and Engineering Management Research Publications

We acquired Johnson BV photometry of the binary Be disk system δ Scorpii during its 2009, 2010, 2011, and 2012 observing seasons and used it to probe the innermost regions of the disk. We found that several disk building events have occurred during this time, resulting in an overall brightening in the V band and reddening of the system. In addition to these long-term trends, we found cyclical variability in each observing season on timescales between 60 and 100 days. We were able to reproduce the changes in the magnitude and color of δ Sco using our theoretical models and …

A Search For Exozodiacal Clouds With Kepler, Christopher C. Stark, Alan P. Boss, Alycia J. Weinberger, Brian K. Jackson, Michael Endl, William D. Cochran, Marshall Johnson, Caroline Caldwell, Eric Agol, Eric B. Ford, Jennifer R. Hall, Khadeejah A. Ibrahim, Jie Li

Brian Jackson

Planets embedded within dust disks may drive the formation of large scale clumpy dust structures by trapping dust into resonant orbits. Detection and subsequent modeling of the dust structures would help constrain the mass and orbit of the planet and the disk architecture, give clues to the history of the planetary system, and provide a statistical estimate of disk asymmetry for future exoEarth-imaging missions. Here, we present the first search for these resonant structures in the inner regions of planetary systems by analyzing the light curves of hot Jupiter planetary candidates identified by the Kepler mission. We detect only one …