Honors in Astronomy
http://hdl.handle.net/1803/686
2024-03-29T14:07:09ZMeasuring Radial Velocities of Low Mass Eclipsing Binaries
http://hdl.handle.net/1803/4838
Measuring Radial Velocities of Low Mass Eclipsing Binaries
Rattray, Rebecca
Due to the complex nature of the spectra of low-mass M type stars, it
is difficult to determine their metallicities and temperatures
directly. By studying eclipsing binary pairs comprising one F, G, or
K type star with an M type star, we are able to use what we know about
the primary star to learn more about the secondary star. Measuring
the orbital reflex motion of the primary star, together with the
eclipse light curve of the M star as it transits the primary star,
allows us to determine the mass, radius, temperature, and metallicity
of the M star.
We studied 23 low mass eclipsing binaries (EBLMs) previously
discovered by SuperWASP photometry. We obtained spectra using the
Cerro Tololo Inter-American Observatory (CTIO) SMARTS 1.5-meter
echelle spectrograph between June 2009 and January 2011. Each EBLM
target was typically observed ~8 times over this time period. The
spectra were processed using standard astronomical software, and a
cross-correlation method was used to measure the radial velocity of
the target star at each observed epoch.
Radial velocities were successfully determined for 21 of the 23 EBLM
target objects. Orbital periods, radial velocity amplitudes, and
eccentricities for these EBLMs could be determined from these radial
velocities together with the preexisting light curves. Using these
values and by assuming a mass for the primary star, we will be able to
calculate the masses of the secondary M type star in each EBLM system.
2011-04-01T00:00:00ZThe distribution of ejected stars around a super massive black hole binary due to three-body scattering
http://hdl.handle.net/1803/4107
The distribution of ejected stars around a super massive black hole binary due to three-body scattering
Benson, Amanda
Honors in Astronomy
2010-04-01T00:00:00ZBlazar Microvariations
http://hdl.handle.net/1803/2944
Blazar Microvariations
Pittman, Cameron W.
In November 2006, the authors collected data on blazars PKS 0537-441, PKS
0447-439, and PKS 0208-5121 from the Cerra Tololo Inter-American Observatory in
Chile. All three blazars are tested for microvariability, first by comparing
relative magnitudes against unvarying stars, then through power spectrum
analysis. The authors used GNU Scientific Library tools for the Fourier
transforms needed for power spectrum analysis.
Fourier transforms break down data into series of periodic functions. Running
power spectra quantitatively illuminate periodicity and variability in data.
The authors tested power spectra by using well-defined functions to better
understand power spectra analysis. Through light curve analysis and power
spectra analysis, the authors found PKS 0537-441 showed microvariability, PKS
0208-512 most likely did not show microvariability, and PKS 0447-439 did not
show microvariability.
Honors in Astronomy
2009-04-20T00:00:00ZExploring the Local Association : a nearby, young kinematic stream of stars in the solar neighborhood
http://hdl.handle.net/1803/730
Exploring the Local Association : a nearby, young kinematic stream of stars in the solar neighborhood
Saling, Chris
During the course of my Honors Research Project, I worked with Dr. David
James to determine whether a group of target stars are members of the Local Association.
I did this by reducing spectroscopic data, taken by Dr. James, in order to determine the
radial velocity and lithium contents of the stars. Using the radial velocity measurements,
the kinematics of each star was then defined by determining their U,V,W space motions.
Lithium measurements were used to establish star youth and provide further evidence to
support membership of the Local Association.
Honors in Astronomy
2008-01-01T00:00:00Z