Testing a hypothesis of the ν Octantis planetary system

Goździewski, Krzysztof; Słonina, Mariusz; Migaszewski, Cezary; Rozenkiewicz, A.

doi:10.1093/mnras/sts652

Cited by 48 publications

(35 citation statements)

References 28 publications

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“…Other strips corresponding to the (1:-5:7) MMR are visible too. Such a complex, fractal-like network of unstable strips in the two-dimensional maps may be interpreted as the Arnold web, as described in Guzzo (2005) for the Solar System, and in the binary ν-Octantis (Goździewski et al 2013). To understand even better the position of the system in the parameter space, we present onedimensional REM scans along the semi-major axis for all the three planets separately (Fig.…”

Section: Dynamical Setup Of the Kepler-30 Systemmentioning

confidence: 99%

The architecture and formation of the Kepler-30 planetary system

Panichi

Goździewski

Migaszewski

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We study the orbital architecture, physical characteristics of planets, formation and long-term evolution of the Kepler-30 planetary system, detected and announced in 2012 by the KEPLER team. We show that the Kepler-30 system belongs to a particular class of very compact and quasi-resonant, yet long-term stable planetary systems. We re-analyse the light curves of the host star spanning Q1-Q17 quarters of the KEPLER mission. A huge variability of the Transit Timing Variations (TTV) exceeding 2 days is induced by a massive Jovian planet located between two Neptune-like companions. The innermost pair is near to the 2:1 mean motion resonance (MMR), and the outermost pair is close to higher order MMRs, such as 17:7 and 7:3. Our re-analysis of photometric data allows us to constrain, better than before, the orbital elements, planets' radii and masses, which are 9.2 ± 0.1, 536 ± 5, and 23.7 ± 1.3 Earth masses for Kepler-30b, Kepler-30c and Kepler-30d, respectively. The masses of the inner planets are determined within ∼ 1% uncertainty. We infer the internal structures of the Kepler-30 planets and their bulk densities in a wide range from (0.19 ± 0.01) g·cm −3 for Kepler-30d, (0.96 ± 0.15) g·cm −3 for Kepler-30b, to (1.71 ± 0.13) g·cm −3 for the Jovian planet Kepler-30c. We attempt to explain the origin of this unique planetary system and a deviation of the orbits from exact MMRs through the planetary migration scenario. We anticipate that the Jupiter-like planet plays an important role in determining the present dynamical state of this system. tems make it possible to further refine their orbital parameters and masses (e.g., Borsato et al. 2014;Barros et al. 2014).In this paper, we report on a new and up-to-date characterization of the Kepler-30 system composed of three planets. These planets have been validated by Fabrycky et al. (2012) on the basis of the very initial Q1-Q6 KEPLER data quarters ( 600 days) as well as by Tingley et al. (2011) on the basis of the first Q0-Q2 quarters.The early studies on this system were focused on the orbital-spin alignment and star-spots detection (Sanchis-Ojeda et al. 2012) or on differential rotation of the parent star (Lanza et al. 2014). Here, we take full advantage of the available light curves of Kepler-30, spanning Q1-Q17 quarters ( 1600 days) to constrain better the masses and orbital elements of the planets.We find the Kepler-30 system particularly interesting and unique in the KEPLER sample for several reasons. One of them is the huge TTV full-amplitude of the innermost planet of 2 days (48 hours), which is two times larger than the TTV fullamplitude of 1 day for the innermost planet in the Kepler-88 system (Nesvorný et al. 2013) dubbed as "the king of the transit c 2017 RAS

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Section: Dynamical Setup Of the Kepler-30 Systemmentioning

confidence: 99%

The architecture and formation of the Kepler-30 planetary system

Panichi

Goździewski

Migaszewski

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…The controversial geometry of ν Oct has been investigated with increasing depth beginning with Eberle & Cuntz (2010) and subsequently by Quarles, Cuntz & Musielak (2012) and Goździewski et al (2013). Goździewski et al explored the system in considerable detail and found that stable solutions consistent with the Ramm et al results existed but were confined to tiny regions of the phase space.…”

Section: Introductionmentioning

confidence: 99%

Line-depth-ratio temperatures for the close binary ν Octantis: new evidence supporting the conjectured circumstellar retrograde planet

Ramm¹

2015

Monthly Notices of the Royal Astronomical Society

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We explore the possibly that either starspots or pulsations are the cause of a periodic radialvelocity signal (P ∼ 400 days) from the K-giant binary ν Octantis (P ∼ 1050 days, e ∼ 0.25), alternatively conjectured to have a retrograde planet. Our study is based on temperatures derived from 22 line-depth ratios (LDRs) for ν Oct and twenty calibration stars. Empirical evidence and stability modelling provide unexpected support for the planet since other standard explanations (starspots, pulsations and additional stellar masses) each have credibility problems. However, the proposed system presents formidable challenges to planet-formation and stability theories: it has by far the smallest stellar separation of any claimed planet-harbouring binary (a bin ∼ 2.6 AU) and an equally unbelievable separation ratio (a pl /a bin ∼ 0.5), hence the necessity that the circumstellar orbit be retrograde.The LDR analysis of 215 ν Oct spectra acquired between 2001-2007, from which the RV perturbation was first revealed, have no significant periodicity at any frequency. The LDRs recover the original 21 stellar temperatures with an average accuracy of 45 ± 25 K. The 215 ν Oct temperatures have a standard deviation of only 4.2 K. Assuming the host primary is not pulsating, the temperatures converted to magnitude differences strikingly mimic the very stable photometric Hipparcos observations 15 years previously, implying the long-term stability of the star and demonstrating a novel use of LDRs as a photometric gauge. Our results provide substantial new evidence that conventional starspots and pulsations are unlikely causes of the RV perturbation. The controversial system deserves continued attention, including with higher resolving-power spectra for bisector and LDR analyses.

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“…Chaotic regions can alter the periodicity of the orbit, as well as the orientation of the orbit relative to some reference direction (i.e., precession of Eulerian angles). Goździewski et al [2013] and Migaszewski et al [2012] demonstrated this principle with a chaos indicator (for details, see Section 4.5).…”

Section: Numerical Search For Periodic Orbits and Resonancesmentioning

confidence: 93%

“…This posed a problem for the confirmation of the exoplanet. However, if one considers an exoplanet in retrograde orbit relative to the orbiting binary, then enlarged regions of stability arise, which would be consistent with the putative exoplanet [Eberle and Cuntz, 2010b, Quarles et al, 2012a, Goździewski et al, 2013. The restricted three-body problem has also been applied to P-type or circumbinary exoplanets.…”

Section: Binary Stellar Systems With a Giant Or Terrestrial Exoplanetmentioning

confidence: 99%

The three-body problem

2014

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Abstract. The three-body problem, which describes three masses interacting through Newtonian gravity without any restrictions imposed on the initial positions and velocities of these masses, has attracted the attention of many scientists for more than 300 years. In this paper, we present a review of the three-body problem in the context of both historical and modern developments. We describe the general and restricted (circular and elliptic) three-body problems, different analytical and numerical methods of finding solutions, methods for performing stability analysis, search for periodic orbits and resonances, and application of the results to some interesting astronomical and space dynamical settings. We also provide a brief presentation of the general and restricted relativistic three-body problems, and discuss their astronomical applications.

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Testing a hypothesis of the ν Octantis planetary system

Cited by 48 publications

References 28 publications

The architecture and formation of the Kepler-30 planetary system

The architecture and formation of the Kepler-30 planetary system

Line-depth-ratio temperatures for the close binary ν Octantis: new evidence supporting the conjectured circumstellar retrograde planet

The three-body problem

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