Doppler Tomography of IP Pegasi

The Home Page of Jeff Bryant

Waylena McCully, Cataclysmic Variable Stars, Vistapro space-art, and fossil collecting.

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CCD Photometry Mathematica Visualization
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My Family & Background

Our Cat, Rigel
Me, a.k.a. Jeff Bryant, and my wife Waylena
Me And Waylena
Our Cat, Remington
Our Cat, Clever
Our Cat, Sabel

I was born in Anderson, Indiana on July 16th, 1973. This is an interesting day as the 16th of July is the day that Apollo 11 was launched, and is also the day that the first fragment of comet Shoemaker-Levy 9 hit the planet Jupiter. Who says my birth wasn't in the stars? I attended Leach Elementary School from 1978 to 1987, this may seem long, but at the time, the jr. high shool was combined with the elementary school. In 1988 I began attending Frankton High School, from which I graduated in 1991. My next step was Ball State University, where I explored my interest in physics and especially astronomy to a great degree. During this time I was able to participate in a research program funded in part by NURO (National Undergraduate Research Observatory). This research centered around the search for late M-class dwarf stars in order to eventually count the number of such stars in an attempt to explain dark matter. I also gained experience in tutoring and grading for numerous classes at the introductory level. Throughout my undergraduate years I was also employed by Marsh Supermarkets for a period of nearly seven years, five of which were spent in the meat department as an apprentice meat cutter. In May 1996, I received my B.S. in physics, with minors in astronomy and math. I also received my M.S. degree in July of 1998, also in physics. As part of my graduate work I was involved with the construction of a stellar model for a binary star known as AK Herculis and the study of IP Peg, more on these below. I am currently employed at Wolfram Research, Inc. - the makers of Mathematica.

My current life is marked most importantly by the fact that on August 16th, 2003, I married my beautiful wife:
Waylena Mae McCully (pictured with me above). We were married in Youngstown, Ohio at the Chapel of the Friendly Bells wedding chapel. Pictures of the ceremony can be seen here.

My Interests

My first interest was in paleontology, shortly followed by a strong interest in astronomy. I also have strong interests in computers, astrophotography, and bicycling. My favorite books belong to the Necroscope series (13 books), by Brian Lumley, to which I am strongly addicted to. Click on the link under My Links to see more about these books, or visit Brian Lumley's website at

I have been priviledged to have access to the Ball State University's Photometrics Star I CCD camera with which I have taken many pictures of the night sky. I also took some pictures of the recent comet Hale-Bopp with my Pentax K-1000. I used a 50 mm lens at f/1.7 along with 1000 ASA Kodak Gold film. The pictures were taken on March 10, 1997 at about 10:45 U.T. Click on the appropriate sidebar buttons to view the pictures.

On January 1, 2002, I was elected the president of the Champaign-Urbana Astronomical Society (CUAS). I decided to take a break in January 2005 and am currently the 5th director. We are a very active organization committed to educating ourselves and the public about astronomy. To find out more about CUAS, visit our website by clicking on the CUAS link under My Links.

All of my research that follows were projects suggested by Dr. Ronald Kaitchuck at Ball State University. He has done extensive research in Algol type eclipsing star systems and in cataclysmic variable star systems. He can be reached by the following E-mail address:

I also have a minor hobbist interest in rendering 3D landscapes, primarily space-related scenes. I use a program called Vistapro to do the renderings and use Photoshop in some rare cases to add lighting effects. It was my Vistapro renderings that led to my introduction to my wife. She is the planetarium show producer at the Staerkel Planetarium at Parkland College in Champaign, IL and she did this kind of rendering in a program called Blender. After my demo at an astro club meeting that she happened to be present at, we talked for some time about the topic and the rest was destiny. I owe my marriage to Vistapro.

Project: AK Herculis (AK Her)

AK Herculis

As a research project I was to study the light curve of a W-Ursa Majoris type eclipsing variable star system known as AK Her. This light curve was to be used to construct a computer model of the star system, including star spots if necessary. The resulting model yielded two F class stars rotating around each other with a period of about 0.42 days. The two stars were in contact, thus forming a contact binary system. Even with this setup, there was a noticeable asymmetry in the light curve maxima, one being less than the other, therefore, something on one side of the star system was causing the luminosity of the system to drop lower than when the opposite side faces us.

Project: IP Pegasi (IP Peg)

Artists concept of Cataclysmic Variable Star IP Peg

More recently, I completed my thesis, "Determination of the Physical Parameters of the Eclipsing Dwarf Nova System IP Peg." Photometric data was collected on November 8, 1997 using the NURO 31-inch telescope which was equipped with a liquid nitrogen cooled, 512x512 CCD camera. To see an computer animation of IP Peg with it's associated light curve, Click Here.

CCD animation of Cataclysmic Variable Star IP Peg

IP Peg has an orbital period of 3.8 hours and undergoes an eclipse due to the high inclination of the system to our line of sight. It is a member of the dwarf nova subclass of cataclysmic variable stars which means that it undergoes a rapid brightening every 100 days or so. Spectroscopic data was also used in the analysis. Spectra were obtained in 1985 and 1988 for IP Peg while in quiescence.

A trailed spectrogram of the hydrogen beta emission lines in 1985 is shown below. Spectrograms are necessary in the construction of Doppler Tomograms which (shown below the spectrogram) allow one to visualize the star system in velocity space.

Trailed spectrogram of Cataclysmic Variable Star IP Peg created with Mathematica

Doppler tomogram of the Cataclysmic Variable Star IP Peg created with Mathematica

This image is a Doppler tomogram created from a trailed spectrogram similar to the one above. It was created using Mathematica 4.2. The reason that the emission line has two components is that most of the light from the system comes from the accretion disk which exhibits Doppler shifting due to the rotation of the disk around the white dwarf star. The sinusoidal shape of the lines is due to the orbital motion of the accretion disk around the center of mass of the system.

Project: UU Aquarii (UU Aqr)

The following link is to an AVI movie constructed from image frames taken of another eclipsing cataclysmic variable star known as UU Aqr.

UU Aqr movie

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