One of the most rewarding aspects of the RFO Research Program is seeing students do genuine science — not simulations or textbook exercises, but original research that contributes to the broader astronomical community. This week, that became especially real: a group of students and their teacher at Buckingham Collegiate Charter Academy in Vacaville submitted a research paper to the Journal of the American Association of Variable Star Observers (JAAVSO).
Their paper, “Decreasing Orbital Period of the BX Pegasi Binary System,” is the product of a full year of work. The student authors — Theresa Ten Hoor, Kyrie Kennedy, Maxwell Bennett, Caydence Gilbreth, Jordan Guttmann, Wyatt Griffin, Audrey Jensen, Laila McGovern, Sylvandra Morphis, Travis Pearson, and Avalon Puma — worked alongside their teacher, Robert Tabor, to conduct a rigorous analysis of a fascinating star system in the constellation Pegasus.
What is BX Pegasi?
BX Pegasi is what astronomers call a W Ursae Majoris (W UMa) overcontact binary — two stars so close to each other that they share a common outer atmosphere, almost like two soap bubbles pressed together. The two stars complete a full orbit around each other in less than seven hours. From Earth, we can observe the system periodically dimming as one star passes in front of or behind the other, producing a characteristic light curve.
What Did the Students Find?
The team analyzed over 13,500 photometric observations drawn from the AAVSO International Database, spanning more than 23 years of data. Using the period-analysis software Peranso and a statistical technique called Analysis of Variance (ANOVA), they carefully measured the precise timing of each eclipse minimum and built an Observed-Computed (O-C) diagram — a powerful tool for detecting subtle changes in orbital timing over time.
Their O-C diagram revealed a clear downward parabolic trend: the eclipses are arriving slightly earlier than a fixed period would predict, and the gap grows over time. The conclusion is unambiguous — BX Peg’s orbital period is decreasing at a rate of approximately 2.57 seconds per year, meaning the two stars are gradually spiraling closer together and orbiting each other faster with each passing year.
This finding is consistent with prior studies of BX Peg by professional astronomers (Alton 2013; Lee et al. 2004), and the team’s careful data cleaning and methodological refinements produced a result that stands on its own scientific merits.
Why Does It Matter?
A decreasing orbital period in a contact binary system can point to several fascinating physical processes: mass transfer from one star to the other, loss of angular momentum through magnetic braking, or — on a very long timescale — the eventual merger of the two stars into a single object. Systems like BX Peg give astronomers a window into the late evolutionary stages of close binary stars, and long-baseline studies like this one are essential to tracking those changes.
An RFO Connection
RFO’s Research Program has supported this work throughout the year. RFO Research Committee member George Loyer is acknowledged in the paper for his contributions to the project, including teaching the students the analysis software and calculations. John Gregg also provided guidance and manuscript feedback.
Read the Paper
The manuscript was submitted to JAAVSO on May 21, 2026. A link to the published paper will be added here once it has been through the journal’s review process.
Congratulations to the students, Mr. Tabor, and everyone at Buckingham Collegiate Charter Academy on this outstanding achievement.