A Refined Orbital Ephemeris for the Intermediate Polar FO Aquarii and Evidence for a Period Derivative

2025/09/26 by Garnavich, Peter, Tweddale, Jordan, Littlefield, Colin
#FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR)

paper · doi:10.48550/arxiv.2509.22786

Abstract

We combine more than 40 years of eclipse timings of the intermediate polar FO Aqr and derive new orbital ephemerides. The eclipse times are best fit with a second order polynomial, implying an 8σ detection of a period derivative. The results show that the orbital period of FO Aqr is currently increasing, with a derivative of P=6.65±0.81×10^-11.

Citations

• Evolutionary Period Changes For 52 Cataclysmic Variables, and the Failure For the Most Fundamental Prediction of the Magnetic Braking Model
• The Intermediate Polar FO Aquarii Has Not Been the Same Since Recovering from a Series of Low States
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Studies in astronomical time series analysis. II - Statistical aspects of spectral analysis of unevenly spaced data

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