On the HU Aquarii planetary system hypothesis
arXiv:1205.4164 · doi:10.1111/j.1365-2966.2012.21341.x
Abstract
In this work, we investigate the eclipse timing of the polar binary HU Aquarii that has been observed for almost two decades. Recently, Qian et al. attributed large (O-C) deviations between the eclipse ephemeris and observations to a compact system of two massive jovian companions. We improve the Keplerian, kinematic model of the Light Travel Time (LTT) effect and re-analyse the whole currently available data set. We add almost 60 new, yet unpublished, mostly precision light curves obtained using the time high-resolution photo-polarimeter OPTIMA, as well as photometric observations performed at the MONET/N, PIRATE and TCS telescopes. We determine new mid--egress times with a mean uncertainty at the level of 1 second or better. We claim that because the observations that currently exist in the literature are non-homogeneous with respect to spectral windows (ultraviolet, X-ray, visual, polarimetric mode) and the reported mid--egress measurements errors, they may introduce systematics that affect orbital fits. Indeed, we find that the published data, when taken literally, cannot be explained by any unique solution. Many qualitatively different and best-fit 2-planet configurations, including self-consistent, Newtonian N-body solutions may be able to explain the data. However, using high resolution, precision OPTIMA light curves, we find that the (O-C) deviations are best explained by the presence of a single circumbinary companion orbiting at a distance of ~4.5 AU with a small eccentricity and having ~7 Jupiter-masses. This object could be the next circumbinary planet detected from the ground, similar to the announced companions around close binaries HW Vir, NN Ser, UZ For, DP Leo or SZ Her, and planets of this type around Kepler-16, Kepler-34 and Kepler-35.
20 pages, 18 figures, accepted to Monthly Notices of the Royal Astronomical Society (MNRAS)
References in corpus (9)
- Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
- The effect of red noise on planetary transit detection
- The Transiting Circumbinary Planets Kepler-34 and Kepler-35
- ULTRACAM: an ultra-fast, triple-beam CCD camera for high-speed astrophysics
- The sdB+M Eclipsing System HW Virginis and its Circumbinary Planets
- Where is the second planet in the HD 160691 planetary system?
- Hunting high and low: XMM monitoring of the eclipsing polar HU Aquarii
- Evidence of Precession of the White Dwarf in Cataclysmic Variables
- Stability constraints in modeling of multi-planet extrasolar systems