My Personal Homepage
Webpage for ASTR 110-07A Lab
Research
In 2005 I conducted an extensive program of optical imaging of a faint
protostar (a thirteenth magnitude EXor object, similar to EX Lup) in an
outburst phase, in collaboration with Dr. Marc Audard of Columbia University.
Our joint observations in the x-ray, optical, infrared, and radio regimes led
to an ApJL article on the interaction between magnetic loops in the stellar
corona and the accretion disk. We suggest that enhanced mass accretion rate
during the outburst phase affected the x-ray emission from this source.
As an outgrowth of this and other research programs, I am a Co-I on two
approved XMM and Chandra x-ray projects.
I have also worked with Dr. Edward Sion on a set of cataclysmic variable (CV)
systems. I modeled archival International Ultraviolet Explorer (IUE) spectra
for dwarf novae, constructing synthetic accretion disk models to match the
continuum levels and thus determining white dwarf masses, system inclination
angles, and accretion rates. For one system (T Leonis), I also analyzed a
spectrum taken during quiescence (when the accretion disk becomes optically
thin, and the exposed underlying white dwarf briefly dominates the
far-ultraviolet spectrum). I determined a photospheric temperature of 16,000
K for this object.
With Dr. Edward Guinan and Dr. Laurence DeWarf, I developed the Sun in
Time project, following the evolution of stars like our Sun at x-ray and
optical wavelengths by studying solar proxies which currently exist across a
range of ages. We confirmed the qualities of the Solar Twin, 18 Sco,
and showed how data obtained in different wavelength regimes can highlight
various physical processes in stars like the Sun.
I am an avid observer, and am particularly interested in young stellar objects
and accretion phenomena. I have begun my graduate studies in Fall 2006,
working with Dr. Jon Holtzman. I am involved in Apache Point Observatory 3.5-m
observations as part of a stellar spectroscopy project.
I will spend Summer 2007 as a research intern at Goddard Space Flight Center,
working on instrumentation for solar satellite telescopes.
Publications
Spectral Analysis of the Nova-Like Variable VY Scl from the High State to the Low State,
R. T. Hamilton, E. M. Sion 2007, PASP, Accepted (Feb 2008)
An International Ultraviolet Explorer Archival Study of Dwarf Novae in Outburst,
R. T. Hamilton, J. A. Urban, E. M. Sion, A. R. Riedel, E. N. Voyer, J. T. Marcy, S. L. Lakatos
2007, ApJ, 667, 1139
X-Ray Spectral Variability During an Outburst in V1118
Ori,
M. Audard, M. Guedel, S. L. Skinner, K. R. Briggs, F. M. Walter,
G. Stringfellow, R. T. Hamilton, & E. F. Guinan 2005, ApJL, 635, 81
Dwarf Novae with Newly Determined Parallaxes: Model Analyses
of VY Aquari, RU Pegasi, and T Leonis,
R. T. Hamilton & E. M. Sion 2004, PASP, 116, 926
Rotation-Activity-Age Relations of Sun-like Stars: In Search of the Solar
Twin,
E. F. Guinan, L. E. DeWarf, & R. T. Hamilton 2006, AJ, In Perpetuity
Meetings
January 2006: American Astronomical Society meeting, The 2005 Accretion Outburst in V1118 Ori: Evidence for A Spectral Change in X-rays
M. Audard, M. Güdel, S. L. Skinner, K. R. Briggs, F. M. Walter,
G. Stringfellow, R. T. Hamilton, & E. F. Guinan
January 2005: American Astronomical Society meeting, Spectroscopy on a Shoestring: Worthwhile Science for Undergraduates
R. T. Hamilton, S. G. Engle, E. F. Guinan, G. P. McCook, & R. P. Wasatonic
June 2004: American Astronomical Society meeting, Dwarf Novae in Outburst with Newly Determined Parallaxes: Analyses of VY Aquari and RU Peg
R. T. Hamilton & E.M. Sion
January 2003: American Astronomical Society meeting, Rotation-Activity-Age Relations of Sun-like Stars: In Search of the Much Coveted Solar Twin
R. T. Hamilton, E. F. Guinan, & L. E. DeWarf
May 2003: American Astronomical Society meeting, Determination of Age, Rotation, and Magnetic Activity Relations for dG, dK, and dM Stars: A Search for Candidates that may be Suitable for Life
J. W. Drescher, E. F. Guinan, L. E. DeWarf, G. P. McCook, R. T. Hamilton, &
I. Ribas
