A dynamical analysis of the proposed HU Aquarii planetary system

Horner, J. and Marshall, J. P. and Wittenmyer, Robert A. and Tinney, C. G. (2011) A dynamical analysis of the proposed HU Aquarii planetary system. Monthly Notices of the Royal Astronomical Society: Letters, 416 (1). L11-L15. ISSN 1745-3925

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It has recently been suggested that the eclipsing polar HU Aquarii is a host to at least two giant planets. We have performed highly detailed dynamical analyses of the orbits of those planets and showed that the proposed system is highly unstable on time-scales of <5 × 10 3 yr. For the coplanar orbits suggested in the discovery Letter, we find stable orbital solutions for the planetary system only if the outer body moves on an orbit that brings it no closer to the host star than ~6 au. The required periastron distance for the outer planet lies approximately 5 Hill radii beyond the orbit of the inner planet, and well beyond the 1σ error bars placed on the orbit of the outer planet in the discovery Letter. If the orbits of the proposed planets are significantly inclined with respect to one another, the median stability increases slightly, but such systems still become destabilized on astronomically minute time-scales (typically within a few 10 4 yr). Only in the highly improbable scenario where the outer planet follows a retrograde but coplanar orbit (i.e. inclined by 180° to the orbit of the inner planet) is there any significant region of stability within the original 1σ orbital uncertainties. Our results suggest that, if there is a second (and potentially, a third planet) in the HU Aquarii system, its orbit is dramatically different from that suggested in the discovery Letter, and that more observations are critically required in order to constrain the nature of the suggested orbital bodies.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2011 The Authors. This publication is copyright. It may be reproduced in whole or in part for the purposes of study, research, or review, but is subject to the inclusion of an acknowledgment of the source.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - No Department
Date Deposited: 21 Jul 2014 23:15
Last Modified: 30 Jan 2017 06:24
Uncontrolled Keywords: close binaries; eclipsing binaries; planetary systems; planets and satellites; dynamical evolution and stability; stars; HU Aquarii; white dwarfs
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020108 Planetary Science (excl. Extraterrestrial Geology)
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020109 Space and Solar Physics
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.1111/j.1745-3933.2011.01087.x
URI: http://eprints.usq.edu.au/id/eprint/25585

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