J/MNRAS/448/1118 HU Aqr planetary system mid-egress moments (Gozdziewski+, 2015)
The HU Aqr planetary system hypothesis revisited.
Gozdziewski K., Slowikowska A., Dimitrov D., Krzeszowski K., Zejmo M.,
Kanbach G., Burwitz V., Rau A., Irawati P., Richichi A., Gawronski M.,
Nowak G., Nasiroglu I., Kubicki D.
<Mon. Not. R. Astron. Soc., 448, 1118-1136 (2015)>
=2015MNRAS.448.1118G 2015MNRAS.448.1118G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Stars, variable ;
Ephemerides
Keywords: techniques: photometric - stars: individual: HU Aqr -
novae, cataclysmic variables - planetary systems
Abstract:
We study the mid-egress eclipse timing data gathered for the
cataclysmic binary HU Aquarii during the years 1993-2014. The (O-C)
residuals were previously attributed to a single ∼7 Jupiter mass
companion in ∼5 AU orbit or to a stable two-planet system with an
unconstrained outermost orbit. We present 22 new observations gathered
between 2011 June and 2014 July with four instruments around the
world. They reveal a systematic deviation of ∼60-120 s from the older
ephemeris. We re-analyse the whole set of the timing data available.
Our results provide an erratum to the previous HU Aqr planetary
models, indicating that the hypothesis for a third and fourth body in
this system is uncertain. The dynamical stability criterion and a
particular geometry of orbits rule out coplanar two-planet
configurations. A putative HU Aqr planetary system may be more
complex, e.g. highly non-coplanar. Indeed, we found examples of
three-planet configurations with the middle planet in a retrograde
orbit, which are stable for at least 1 Gyr, and consistent with the
observations. The (O-C) may be also driven by oscillations of the
gravitational quadrupole moment of the secondary, as predicted by the
Lanza et al. modification of the Applegate mechanism. Further
systematic, long-term monitoring of HU Aqr is required to interpret
the (O-C) residuals.
Description:
In this paper, we gathered the new measurements in the originally
submitted manuscript and the new observations published by Bours et al.
(2014MNRAS.445.1924B 2014MNRAS.445.1924B). We verified that the results obtained without
and with their measurements, respectively, differ only up to
quantitative sense (i.e. the best-fitting parameters are slightly
altered). With the aim of publishing the most up-to-date results
possible, we re-analysed available timing data of the HU Aqr eclipses,
which are collected in the appendix.
Table A1 in this appendix collects mid-egress moments published in the
literature, as well as our new data, which were used for the analysis
of (O-C) in this paper.
Objects:
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RA (ICRS) DE Designation(s)
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21 07 58.19 -05 17 40.5 HU Aqr = V* HU Aqr
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 41 215 Mid-egress moments available in the literature.
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See also:
V/123 : Catalog of Cataclysmic Variables (Downes+ 2001-2006)
J/AJ/147/45 : Kepler mission. IV. Eclipse times for close binaries
(Conroy+, 2014)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Cycle [0/89340] Cycle number (1)
7- 19 F13.7 d MJD The moment of the mid-egress in Modified Julian
Date
21- 29 F9.7 d e_MJD Uncertainty in MJD
31- 39 A9 --- Inst Instrument used for the observation
41 I1 --- r_Inst [1/6] Instrument reference (2)
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Note (1): With respect to the epoch BJD 2449102.9200026 (the BJD of the first
observation in Schwope et al. 1993A&A...271L..25S 1993A&A...271L..25S). The L=0 cycle here
is shifted to epoch T0=BJD 2453504.8882940 with constant offset of
50702 cycles.
Note (2): Instruments are code-named in accord with a particular source
publication.
Reference as follows:
1 = Schwope et al. (2001A&A...375..419S 2001A&A...375..419S);
2 = Schwarz et al. (2009A&A...496..833S 2009A&A...496..833S);
3 = Qian et al. (2011MNRAS.414L..16Q 2011MNRAS.414L..16Q);
4 = Gozdziewski et al. (2012MNRAS.425..930G 2012MNRAS.425..930G);
5 = Bours et al. (2014MNRAS.445.1924B 2014MNRAS.445.1924B);
6 = This work.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 20-Nov-2017