Making hot Jupiters in stellar clusters – II. Efficient formation in binary systems

Li, Daohai; Mustill, Alexander J; Davies, Melvyn B; Gong, Yan-Xiang

doi:10.1093/mnras/stad3207

Cited by 5 publications

(1 citation statement)

References 110 publications

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“…A significant unanswered question in astrophysics is to what degree does the star-forming environment shape the architectures of planetary systems? For instance, are hot Jupiters (Dawson & Johnson 2018) formed from the migration of planets in disks (Masset & Papaloizou 2003), or are they produced later via dynamical instabilities in the planetary systems caused by interactions with other stars (Wu & Murray 2003;Benkendorff et al 2024;Li et al 2024)?…”

Section: Introductionmentioning

confidence: 99%

No Signature of the Birth Environment of Exoplanets from Their Host Stars’ Mahalanobis Phase Space

Blaylock-Squibbs,

Parker,

Daffern-Powell

2024

ApJ

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The architectures of extrasolar planetary systems often deviate considerably from the “standard” model for planet formation, which is largely based on our own solar system. In particular, gas giants on close orbits are not predicted by planet formation theory and so some processes are thought to move the planets closer to their host stars. Recent research has suggested that hot-Jupiter host stars display a different phase space compared to stars that do not host hot Jupiters. This has been attributed to these stars forming in star-forming regions of high stellar density, where dynamical interactions with passing stars have perturbed the planets. We test this hypothesis by quantifying the phase space of planet-hosting stars in dynamical N-body simulations of star-forming regions. We find that stars that retain their planets have a higher phase space than nonhosts, regardless of their initial physical density. This is because an imprint of the kinematic substructure from the regions birth is retained, as these stars have experienced fewer and less disruptive encounters than stars whose planets have been liberated and become free-floating. However, host stars whose planets remain bound but have had their orbits significantly altered by dynamical encounters are also primarily found in high phase space regimes. We therefore corroborate other research in this area that has suggested the high phase space of hot-Jupiter host stars is not caused by dynamical encounters or stellar clustering, but rather reflects an age bias in that these stars are (kinematically) younger than other exoplanet host stars.

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Section: Introductionmentioning

confidence: 99%

No Signature of the Birth Environment of Exoplanets from Their Host Stars’ Mahalanobis Phase Space

Blaylock-Squibbs,

Parker,

Daffern-Powell

2024

ApJ

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Search for giant planets in M 67 V: A warm Jupiter orbiting the turn-off star S1429

Thomas,

Saglia,

Pasquini

et al. 2024

A&A

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Planets orbiting members of open or globular clusters offer a great opportunity to study exoplanet populations systematically, as stars within clusters provide a mostly homogeneous sample, at least in chemical composition and stellar age. However, even though there have been coordinated efforts to search for exoplanets in stellar clusters, only a small number of planets have been detected. One successful example is the seven-year radial velocity (RV) survey `Search for giant planets in M67' of 88 stars in the open cluster M67, which led to the discovery of five giant planets, including three close-in ($P < 10$ days) hot-Jupiters. In this work, we continue and extend the observation of stars in M67, with the aim being to search for additional planets. We conducted spectroscopic observations with the Habitable Planet Finder (HPF), HARPS, HARPS-North, and SOPHIE spectrographs of 11 stars in M67. Six of our targets showed a variation or long-term trends in their RV during the original survey, while the other five were not observed in the original sample, bringing the total number of stars to 93. An analysis of the RVs reveals one additional planet around the turn-off point star S1429 and provides solutions for the orbits of stellar companions around S2207 and YBP2018. S1429 b is a warm-Jupiter on a likely circular orbit with a period of $77.48_ $ days and a minimum mass of $ M i = 1.80 0.2$ M$_ J $. We update the hot-Jupiter occurrence rate in M67 to include the five new stars, deriving $4.2_ <!PCT!>$ when considering all stars, and $5.4_ <!PCT!>$ if binary star systems are removed.

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Running with the bulls

Winter,

Benisty,

Shuai

et al. 2024

A&A

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Stars and planets form in regions of enhanced stellar density, subjecting protoplanetary discs to gravitational perturbations from neighbouring stars. Observations in the Taurus star-forming region have uncovered evidence of at least three recent, star-disc encounters that have truncated discs (HV/DO Tau, RW Aurigae, and UX Tau), raising questions about the frequency of such events. We aim to assess the probability of observing truncating star-disc encounters in Taurus. We generated a physically motivated dynamical model including binaries and a spatial-kinematic substructure to follow the historical dynamical evolution of the Taurus star-forming region. We used this model to track star-disc encounters and the resulting outer disc truncation over the lifetime of Taurus. A quarter of discs are truncated below 30 au by dynamical encounters, but this truncation mostly occurs in binaries over the course of a few orbital periods, on a timescale $ 0.1$ Myr. Nonetheless, some truncating encounters still occur up to the present age of Taurus. Strongly truncating encounters (ejecting $ 10$ percent of the disc mass) occur at a rate $ $, sufficient to explain the encounter between HV and DO Tau $ 0.1$ Myr ago. If encounters that eject only $ 1$ percent of the disc mass are responsible for RW Aurigae and UX Tau, then they are also expected with encounter rate $ enc 200$ Myr$^ $. However, the observed sample of recent encounters is probably incomplete, since these examples occurred in systems that are not consistent with a random drawing from the mass function. One more observed example would statistically imply additional physics, such as replenishment of the outer disc material. The marginal consistency of the frequency of observed recent star-disc encounters with theoretical expectations underlines the value of future large surveys searching for external structures associated with recent encounters. The outcome of such a survey offers a highly constraining, novel probe of protoplanetary disc physics.

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Making hot Jupiters in stellar clusters – II. Efficient formation in binary systems

Cited by 5 publications

References 110 publications

No Signature of the Birth Environment of Exoplanets from Their Host Stars’ Mahalanobis Phase Space

No Signature of the Birth Environment of Exoplanets from Their Host Stars’ Mahalanobis Phase Space

Search for giant planets in M 67 V: A warm Jupiter orbiting the turn-off star S1429

Running with the bulls

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