SOPHIE velocimetry of<i>Kepler</i>transit candidates

Santerne, A.; Moutou, C.; Tsantaki, M.; Bouchy, F.; Hébrard, G.; Adibekyan, V.; Almenara, J. M.; Amard, Louis; Barros, S. C. C.; Boisse, I.; Bonomo, A. S.; Bruno, G.; Courcol, B.; Deleuil, M.; Demangeon, O.; Díaz, R. F.; Guillot, T.; Havel, M.; Montagnier, G.; Rajpurohit, A. S.; Rey, J.; Santos, N. C.

doi:10.1051/0004-6361/201527329

Cited by 259 publications

(291 citation statements)

References 197 publications

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“…In the top three panels, red solid, blue dashed and green dotted lines show the distributions from the simulations after 5 Gyr, 10 Gyr and after a random time ('t x '), combining results from the three viscous time-scales t V,1 . Black crosses with error bars indicate the observations from Santerne et al (2016), and the orbital periods of the three HJs in stellar triples known to date, WASP-12, HAT-8-P and KELT-4Ab, are indicated with the vertical black dotted lines. Black open circles show the distribution from Fig.…”

Section: Hj Orbital Period Distributionmentioning

confidence: 99%

“…Companions of HJs in the observed sample of Santerne et al (2016) are poorly constrained, and so it is unclear to which extent the HJ orbital period distribution is different for single stars compared to higher-order systems. The orbital periods of the three HJs observed in triple systems so far, indicated with the black vertical dotted lines in Fig.…”

Section: Hj Orbital Period Distributionmentioning

confidence: 99%

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On the formation of hot and warm Jupiters via secular high-eccentricity migration in stellar triples

Hamers

2017

Mon. Not. R. Astron. Soc.

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Hot Jupiters (HJs) are Jupiter-like planets orbiting their host star in tight orbits of a few days. They are commonly believed not to have formed in situ, requiring inwards migration towards the host star. One of the proposed migration scenarios is secular high-eccentricity or high-e migration, in which the orbit of the planet is perturbed to high eccentricity by secular processes, triggering strong tidal evolution and orbital migration. Previous theoretical studies have considered secular excitation in stellar binaries. Recently, a number of HJs have been observed in stellar triple systems. In the latter, the secular dynamics are much richer compared to stellar binaries, and HJs could potentially be formed more efficiently. Here, we investigate this possibility by modeling the secular dynamical and tidal evolution of planets in two hierarchical configurations in stellar triple systems. We find that the HJ formation efficiency is higher compared to stellar binaries, but only by at most a few tens of per cent. The orbital properties of the HJs formed in the simulations are very similar to HJs formed in stellar binaries, and similarly to studies of the latter we find no significant number of warm Jupiters. HJs are only formed in our simulations for triples with specific orbital configurations, and our constraints are approximately consistent with current observations. In future, this allows to rule out high-e migration in stellar triples if a HJ is detected in a triple grossly violating these constraints.

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Section: Hj Orbital Period Distributionmentioning

confidence: 99%

Section: Hj Orbital Period Distributionmentioning

confidence: 99%

On the formation of hot and warm Jupiters via secular high-eccentricity migration in stellar triples

Hamers

2017

Mon. Not. R. Astron. Soc.

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“…Feng et al 2015;Santerne et al 2016;Moutou et al 2015). The frequency of systems with long-period giant planets (e.g.…”

Section: Introductionmentioning

confidence: 99%

An extreme planetary system around HD 219828

Santos

Santerne

Faria

et al. 2016

A&A

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Context. With about 2000 extrasolar planets confirmed, the results show that planetary systems have a whole range of unexpected properties. This wide diversity provides fundamental clues to the processes of planet formation and evolution. Aims. We present a full investigation of the HD 219828 system, a bright metal-rich star for which a hot Neptune has previously been detected. Methods. We used a set of HARPS, SOPHIE, and ELODIE radial velocities to search for the existence of orbiting companions to HD 219828. The spectra were used to characterise the star and its chemical abundances, as well as to check for spurious, activity induced signals. A dynamical analysis is also performed to study the stability of the system and to constrain the orbital parameters and planet masses. Results. We announce the discovery of a long period (P = 13.1 yr) massive (m sin i = 15.1 M Jup ) companion (HD 219828 c) in a very eccentric orbit (e = 0.81). The same data confirms the existence of a hot Neptune, HD 219828 b, with a minimum mass of 21 M ⊕ and a period of 3.83 days. The dynamical analysis shows that the system is stable, and that the equilibrium eccentricity of planet b is close to zero. Conclusions. The HD 219828 system is extreme and unique in several aspects. First, ammong all known exoplanet systems it presents an unusually high mass ratio. We also show that systems like HD 219828, with a hot Neptune and a long-period massive companion are more frequent than similar systems with a hot Jupiter instead. This suggests that the formation of hot Neptunes follows a different path than the formation of their hot jovian counterparts. The high mass, long period, and eccentricity of HD 219828 c also make it a good target for Gaia astrometry as well as a potential target for atmospheric characterisation, using direct imaging or high-resolution spectroscopy. Astrometric observations will allow us to derive its real mass and orbital configuration. If a transit of HD 219828 b is detected, we will be able to fully characterise the system, including the relative orbital inclinations. With a clearly known mass, HD 219828 c may become a benchmark object for the range in between giant planets and brown dwarfs.

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“…They note that it is inconsistent with the results of ground-based transit surveys, for which they estimate an occurrence ratio of 0.05%.They reckon that a major factor for explaining the discrepancy may be that ground-based surveys are biased in their detection of transits smaller than 1%. Likewise, Santerne et al (2016) conducted a systematic survey of Kepler (Borucki et al 2010) planetary candidates, using radial velocities to determine their masses. They were able to derive the occurrence rate of brown dwarfs and giant planets on orbital periods up to 400 days.…”

Section: Introductionmentioning

confidence: 99%

Can brown dwarfs survive on close orbits around convective stars?

Damiani

Díaz

2016

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Context. The mass range of brown dwarfs extends across the planetary domain to stellar objects. There is a relative paucity of brown dwarfs companions around FGKM-type stars compared to exoplanets for orbital periods of less than a few years, but most of the short-period brown dwarf companions that are fully characterised by transits and radial velocities are found around F-type stars. Aims. We examine the hypothesis that brown dwarf companions could not survive on close orbit around stars with important convective envelopes because the tides and angular momentum loss, the result of magnetic braking, would lead to a rapid orbital decay with the companion being quickly engulfed. Methods. We use a classical Skumanich-type braking law and constant time-lag tidal theory to assess the characteristic timescale for orbital decay for the brown dwarf mass range as a function of the host properties. Results. We find that F-type stars may host massive companions for a significantly longer time than G-type stars for a given orbital period, which may explain the paucity of G-type hosts for brown dwarfs with an orbital period less than five days. On the other hand, we show that the small radius of early M-type stars contributes to orbital decay timescales that are only half those of F-type stars, despite their more efficient tidal dissipation and magnetic braking. For fully convective later type M-dwarfs, orbital decay timescales could be orders of magnitude greater than for F-type stars. Moreover, we find that, for a wide range of values of tidal dissipation efficiency and magnetic braking, it is safe to assume that orbital decay for massive companions can be neglected for orbital periods greater than ten days. Conclusions. For orbital periods greater than ten days, brown dwarf occurrence should largely be unaffected by tidal decay, whatever the mass of the host. On closer orbital periods, the rapid engulfment of massive companions could explain the lack of G and K-type hosts in the sample of known systems with transiting brown dwarfs. However, the paucity of M-type hosts cannot be an effect of tidal decay alone, but may be the result of a selection effect in the sample and/or the formation mechanism.

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SOPHIE velocimetry ofKeplertransit candidates

Cited by 259 publications

References 197 publications

On the formation of hot and warm Jupiters via secular high-eccentricity migration in stellar triples

On the formation of hot and warm Jupiters via secular high-eccentricity migration in stellar triples

An extreme planetary system around HD 219828

Can brown dwarfs survive on close orbits around convective stars?

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