Planet formation in post‐common‐envelope binaries

Schleicher, Dominik R. G.; Völschow, Marcel; Banerjee, Rinti; Hessman, F. V.

doi:10.1002/asna.201412184

Cited by 36 publications

(9 citation statements)

References 49 publications

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“…A hybrid scenario may be also possible, with accretion of the ejected gas onto already existing planets. Several studies have been car-ried out on this matter and some authors favor one scenario over the other (see e.g., Völschow et al 2014;Schleicher & Dreizler 2014;Bear & Soker 2014;Schleicher et al 2015). In any case, these scenarios must take into account that ∼90% of the PCEBs, as found by Zorotovic & Schreiber (2013), have observed apparent period variations, implying that the hypothetical planets are very good at surviving the PCEB formation process and/or the common envelope material is very efficient in forming planets.…”

Section: Introductionmentioning

confidence: 99%

Applegate mechanism in post-common-envelope binaries: Investigating the role of rotation

Navarrete

Schleicher

Zamponi

et al. 2018

A&A

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Context. Eclipsing time variations are observed in many close binary systems. In particular, for several post-common-envelope binaries (PCEBs) that consist of a white dwarf and a main sequence star, the Observed minus Calculated (O-C) diagram suggests that real or apparent orbital period variations are driven by Jupiter-mass planets or as a result of magnetic activity, the so-called Applegate mechanism. The latter explains orbital period variations as a result of changes in the stellar quadrupole moment due to magnetic activity. Aims. In this work we explore the feasibility of driving eclipsing time variations via the Applegate mechanism for a sample of PCEB systems, including a range of different rotation rates. Methods. We used the MESA code to evolve 12 stars with different masses and rotation rates. We applied simple dynamo models to their radial profiles to investigate the scale at which the predicted activity cycle matches the observed modulation period, and quantifiy the uncertainty. We further calculated the required energies to drive the Applegate mechanism. Results. We show that the Applegate mechanism is energetically feasible in 5 PCEB systems. In RX J2130.6+4710, it may be feasible as well considering the uncertainties. We note that these are the systems with the highest rotation rate compared to the critical rotation rate of the main-sequence star.Conclusions. The results suggest that the ratio of physical to critical rotation rate in the main sequence star is an important indicator for the feasibility of Applegate's mechanism, but exploring larger samples will be necessary to probe this hypothesis.

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Section: Introductionmentioning

confidence: 99%

Applegate mechanism in post-common-envelope binaries: Investigating the role of rotation

Navarrete

Schleicher

Zamponi

et al. 2018

A&A

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“…The latter correspond to massive giant planets of several Jupiter masses on planetary orbits of a few AU. It has been suggested that at least some of these planets may have a second-generation origin (Völschow et al 2014;Schleicher & Dreizler 2014;Bear & Soker 2014;Schleicher et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Eclipsing time variations in close binary systems: Planetary hypothesis vs. Applegate mechanism

Völschow

Schleicher

Perdelwitz

et al. 2016

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The observed eclipsing time variations in post-common-envelope binaries (PCEBs) can be interpreted as potential evidence for massive Jupiter-like planets, or as a result of magnetic activity, leading to quasi-periodic changes in the quadrupole moment of the secondary star. The latter is commonly referred to as the Applegate mechanism. We employ an improved version of Applegate's model including the angular momentum exchange between a finite shell and the core of the star. The framework is employed to derive the general conditions under which the Applegate mechanism can work, and is subsequently applied to a sample of 16 close binary systems with potential planets, including eleven PCEBs. Further, we present a detailed derivation and study of analytical models that allow for an straightforward extension to other systems. Using our full numerical framework, we show that the Applegate mechanism can clearly explain the observed eclipsing time variations in four of the systems, while the required energy to produce the quadrupole moment variations is too high in at least eight systems. In the remaining four systems, the required energy is comparable to the available energy produced by the stars, which we consider borderline cases. Therefore, the Applegate mechanism cannot uniquely explain the observed period time variations for this entire population. Even in systems where the required energy is too high, the Applegate mechanism may provide an additional scatter, which needs to be considered in the derivation and analysis of planetary models.

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“…Schleicher & Dreizler (2014) studied 12 PCEBs, elaborating on NN Ser. A recent summary of the question on whether the planets are first-generation planets, i.e., were formed with the stellar binary system, or second generation planets (e.g, Völschow et al 2014), i.e., formed in the post-CE phase from a circumbinary disk, is given by Bear & Soker (2014) and Schleicher et al (2015). We note that PCEBs are only one possible formation route to RPNs…”

Section: Real Planetary Nebula (Rpn) Formationmentioning

confidence: 90%

Planetary systems and real planetary nebulae from planet destruction near white dwarfs

Bear

Soker

2015

Monthly Notices of the Royal Astronomical Society

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We suggest that tidal destruction of Earth-like and icy planets near a white dwarf (WD) might lead to the formation of one or more low-mass − Earthlike and lighter − planets in tight orbits around the WD. The formation of the new WD planetary system starts with a tidal break-up of the parent planet to planetesimals near the tidal radius of about 1R ⊙ . Internal stress forces keep the planetesimal from further tidal break-up when their radius is less than about 100 km. We speculate that the planetesimals then bind together to form new subEarth daughter-planets at a few solar radii around the WD. More massive planets that contain hydrogen supply the WD with fresh nuclear fuel to reincarnate its stellar-giant phase. Some of the hydrogen will be inflated in a large envelope. The envelope blows a wind to form a nebula that is later (after the entire envelope is lost) ionized by the hot WD. We term this glowing ionized nebula that originated from a planet a real planetary nebula (RPN). This preliminary study of daughterplanets from a planet (DPP) and the RPN scenarios are of speculative nature. More detail studies must follow to establish whether the suggested scenarios can indeed take place.

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Planet formation in post‐common‐envelope binaries

Cited by 36 publications

References 49 publications

Applegate mechanism in post-common-envelope binaries: Investigating the role of rotation

Applegate mechanism in post-common-envelope binaries: Investigating the role of rotation

Eclipsing time variations in close binary systems: Planetary hypothesis vs. Applegate mechanism

Planetary systems and real planetary nebulae from planet destruction near white dwarfs

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