scholarly journals Cool Jupiters greatly outnumber their toasty siblings: occurrence rates from the Anglo-Australian Planet Search

2019 ◽  
Vol 492 (1) ◽  
pp. 377-383 ◽  
Author(s):  
Robert A Wittenmyer ◽  
Songhu Wang ◽  
Jonathan Horner ◽  
R P Butler ◽  
C G Tinney ◽  
...  
Keyword(s):  
Solar System ◽  
Radial Velocity ◽  
Planetary System ◽  
Planetary Systems ◽  
Giant Planets ◽  
Occurrence Rate ◽  
Hot Jupiters ◽  
The Past ◽  
Order Of Magnitude

ABSTRACT Our understanding of planetary systems different to our own has grown dramatically in the past 30 yr. However, our efforts to ascertain the degree to which the Solar system is abnormal or unique have been hindered by the observational biases inherent to the methods that have yielded the greatest exoplanet hauls. On the basis of such surveys, one might consider our planetary system highly unusual – but the reality is that we are only now beginning to uncover the true picture. In this work, we use the full 18-yr archive of data from the Anglo-Australian Planet Search to examine the abundance of ‘cool Jupiters’ – analogues to the Solar system’s giant planets, Jupiter and Saturn. We find that such planets are intrinsically far more common through the cosmos than their siblings, the hot Jupiters. We find that the occurrence rate of such ‘cool Jupiters’ is $6.73^{+2.09}_{-1.13}$ per cent, almost an order of magnitude higher than the occurrence of hot Jupiters (at $0.84^{+0.70}_{-0.20}$ per cent). We also find that the occurrence rate of giant planets is essentially constant beyond orbital distances of ∼1 au. Our results reinforce the importance of legacy radial velocity surveys for the understanding of the Solar system’s place in the cosmos.

The Long View of Planetary Systems

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
Milky Way ◽  
Planetary Systems ◽  
Giant Planets ◽  
Milky Way Galaxy ◽  
Population Statistics ◽  
The Past ◽  
General Terms ◽  
The Galaxy ◽  
The Universe

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.

scholarly journals Fly-by encounters between two planetary systems I: Solar system analogues

2019 ◽  
Vol 488 (1) ◽  
pp. 1366-1376 ◽  
Author(s):  
Daohai Li ◽  
Alexander J Mustill ◽  
Melvyn B Davies
Keyword(s):  
Solar System ◽  
Planetary System ◽  
Planetary Systems ◽  
Open Clusters ◽  
Giant Planets ◽  
Direct Imaging ◽  
Solar Mass ◽  
Close Encounters ◽  
Large Numbers

ABSTRACTStars formed in clusters can encounter other stars at close distances. In typical open clusters in the Solar neighbourhood containing hundreds or thousands of member stars, 10–20 per cent of Solar-mass member stars are expected to encounter another star at distances closer than 100 au. These close encounters strongly perturb the planetary systems, directly causing ejection of planets or their capture by the intruding star, as well as exciting the orbits. Using extensive N-body simulations, we study such fly-by encounters between two Solar system analogues, each with four giant planets from Jupiter to Neptune. We quantify the rates of loss and capture immediately after the encounter, e.g. the Neptune analogue is lost in one in four encounters within 100 au, and captured by the flying-by star in 1 in 12 encounters. We then perform long-term (up to 1 Gyr) simulations investigating the ensuing post-encounter evolution. We show that large numbers of planets are removed from systems due to planet–planet interactions and that captured planets further enhance the system instability. While encounters can initially leave a planetary system containing more planets by inserting additional ones, the long-term instability causes a net reduction in planet number. A captured planet ends up on a retrograde orbit in half of the runs in which it survives for 1Gyr; also, a planet bound to its original host star but flipped during the encounter may survive. Thus, encounters between planetary systems are a channel to create counter-rotating planets, This would happen in around 1 per cent of systems, and such planets are potentially detectable through astrometry or direct imaging.

scholarly journals Planetary Systems

1999 ◽  
Vol 172 ◽  
pp. 313-316
Author(s):  
Pawel Artymowicz
Keyword(s):  
Radial Velocity ◽  
Main Sequence ◽  
Direct Evidence ◽  
Planetary System ◽  
Planetary Systems ◽  
Main Sequence Stars ◽  
The Past ◽  
Exoplanetary Systems ◽  
Beta Pictoris

AbstractThe past decade brought direct evidence of the previously surmised exoplanetary systems. A variety of planetary system types exist those around pulsars, around both young and old main-sequence stars (as evidenced by planetesimal disks of the Beta Pictoris-type), and the mature giant exoplanets found in radial velocity surveys. The surprising diversity of the exoplanetary systems is addressed by several theories of their origin.

scholarly journals On secular resonances of small bodies in the planetary systems

2006 ◽  
Vol 2 (S236) ◽  
pp. 77-84
Author(s):  
Jianghui Ji ◽  
L. Liu ◽  
G. Y. Li
Keyword(s):  
Solar System ◽  
Planetary System ◽  
Planetary Systems ◽  
Giant Planets ◽  
Small Bodies ◽  
Secular Resonances ◽  
Mean Motion Resonances ◽  
The Earth ◽  
Habitable Zones ◽  
Earth Like Planets

AbstractWe investigate the secular resonances for massless small bodies and Earth-like planets in several planetary systems. We further compare the results with those of Solar System. For example, in the GJ 876 planetary system, we show that the secular resonances ν1 and ν2 (respectively, resulting from the inner and outer giant planets) can excite the eccentricities of the Earth-like planets with orbits 0.21≤ a <0.50 AU and eject them out of the system in a short timescale. However, in a dynamical sense, the potential zones for the existence of Earth-like planets are in the area 0.50≤ a ≤1.00 AU, and there exist all stable orbits last up to 105 yr with low eccentricities. For other systems, e.g., 47 UMa, we also show that the Habitable Zones for Earth-like planets are related to both secular resonances and mean motion resonances in the systems.

scholarly journals Tidally induced stellar oscillations: converting modelled oscillations excited by hot Jupiters into observables

2020 ◽  
Vol 500 (2) ◽  
pp. 2711-2731
Author(s):  
Andrew Bunting ◽  
Caroline Terquem
Keyword(s):  
Radial Velocity ◽  
Orbital Period ◽  
Planetary Systems ◽  
Velocity Signal ◽  
Convective Flux ◽  
Hot Jupiters ◽  
Stellar Oscillations ◽  
Orbital Periods ◽  
Hot Jupiter

ABSTRACT We calculate the conversion from non-adiabatic, non-radial oscillations tidally induced by a hot Jupiter on a star to observable spectroscopic and photometric signals. Models with both frozen convection and an approximation for a perturbation to the convective flux are discussed. Observables are calculated for some real planetary systems to give specific predictions. The photometric signal is predicted to be proportional to the inverse square of the orbital period, P−2, as in the equilibrium tide approximation. However, the radial velocity signal is predicted to be proportional to P−1, and is therefore much larger at long orbital periods than the signal corresponding to the equilibrium tide approximation, which is proportional to P−3. The prospects for detecting these oscillations and the implications for the detection and characterization of planets are discussed.

scholarly journals No evidence for interstellar planetesimals trapped in the Solar system

2020 ◽  
Vol 497 (1) ◽  
pp. L46-L49 ◽  
Author(s):  
A Morbidelli ◽  
K Batygin ◽  
R Brasser ◽  
S N Raymond
Keyword(s):  
Solar System ◽  
Oort Cloud ◽  
Giant Planets ◽  
Asteroid Belt ◽  
Interstellar Space ◽  
Fast Decay ◽  
Early Solar System ◽  
The Past ◽  
Solar System Bodies ◽  
Main Asteroid Belt

ABSTRACT In two recent papers published in MNRAS, Namouni and Morais claimed evidence for the interstellar origin of some small Solar system bodies, including: (i) objects in retrograde co-orbital motion with the giant planets and (ii) the highly inclined Centaurs. Here, we discuss the flaws of those papers that invalidate the authors’ conclusions. Numerical simulations backwards in time are not representative of the past evolution of real bodies. Instead, these simulations are only useful as a means to quantify the short dynamical lifetime of the considered bodies and the fast decay of their population. In light of this fast decay, if the observed bodies were the survivors of populations of objects captured from interstellar space in the early Solar system, these populations should have been implausibly large (e.g. about 10 times the current main asteroid belt population for the retrograde co-orbital of Jupiter). More likely, the observed objects are just transient members of a population that is maintained in quasi-steady state by a continuous flux of objects from some parent reservoir in the distant Solar system. We identify in the Halley-type comets and the Oort cloud the most likely sources of retrograde co-orbitals and highly inclined Centaurs.

scholarly journals On the survival of resonant and non-resonant planetary systems in star clusters

2020 ◽  
Vol 497 (2) ◽  
pp. 1807-1825
Author(s):  
Katja Stock ◽  
Maxwell X Cai ◽  
Rainer Spurzem ◽  
M B N Kouwenhoven ◽  
Simon Portegies Zwart
Keyword(s):  
Solar System ◽  
Star Clusters ◽  
Planetary Systems ◽  
Dynamical Evolution ◽  
Giant Planets ◽  
Mean Motion Resonances ◽  
Orbital Parameters ◽  
Eccentric Orbits ◽  
The Individual ◽  
Exoplanet Systems

ABSTRACT Despite the discovery of thousands of exoplanets in recent years, the number of known exoplanets in star clusters remains tiny. This may be a consequence of close stellar encounters perturbing the dynamical evolution of planetary systems in these clusters. Here, we present the results from direct N-body simulations of multiplanetary systems embedded in star clusters containing N = 8k, 16k, 32k, and 64k stars. The planetary systems, which consist of the four Solar system giant planets Jupiter, Saturn, Uranus, and Neptune, are initialized in different orbital configurations, to study the effect of the system architecture on the dynamical evolution of the entire planetary system, and on the escape rate of the individual planets. We find that the current orbital parameters of the Solar system giants (with initially circular orbits, as well as with present-day eccentricities) and a slightly more compact configuration, have a high resilience against stellar perturbations. A configuration with initial mean-motion resonances of 3:2, 3:2, and 5:4 between the planets, which is inspired by the Nice model, and for which the two outermost planets are usually ejected within the first 105 yr, is in many cases stabilized due to the removal of the resonances by external stellar perturbation and by the rapid ejection of at least one planet. Assigning all planets the same mass of 1 MJup almost equalizes the survival fractions. Our simulations reproduce the broad diversity amongst observed exoplanet systems. We find not only many very wide and/or eccentric orbits, but also a significant number of (stable) retrograde orbits.

scholarly journals The Pan-Pacific Planet Search – VIII. Complete results and the occurrence rate of planets around low-luminosity giants

2019 ◽  
Vol 491 (4) ◽  
pp. 5248-5257 ◽  
Author(s):  
Robert A Wittenmyer ◽  
R P Butler ◽  
Jonathan Horner ◽  
Jake Clark ◽  
C G Tinney ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Main Sequence ◽  
Giant Planets ◽  
Occurrence Rate ◽  
Velocity Measurements ◽  
Intermediate Mass ◽  
Giant Stars ◽  
Intermediate Mass Stars ◽  
Final Data ◽  
Solar Type

ABSTRACT Our knowledge of the populations and occurrence rates of planets orbiting evolved intermediate-mass stars lags behind that for solar-type stars by at least a decade. Some radial velocity surveys have targeted these low-luminosity giant stars, providing some insights into the properties of their planetary systems. Here, we present the final data release of the Pan-Pacific Planet Search (PPPS), a 5 yr radial velocity survey using the 3.9 m Anglo-Australian Telescope. We present 1293 precise radial velocity measurements for 129 stars, and highlight 6 potential substellar-mass companions, which require additional observations to confirm. Correcting for the substantial incompleteness in the sample, we estimate the occurrence rate of giant planets orbiting low-luminosity giant stars to be approximately 7.8$^{+9.1}_{-3.3}$ per cent. This result is consistent with the frequency of such planets found to orbit main-sequence A-type stars, from which the PPPS stars have evolved.

scholarly journals Turning solar systems into extrasolar planetary systems in stellar clusters

2010 ◽  
Vol 6 (S276) ◽  
pp. 304-307
Author(s):  
Melvyn B. Davies
Keyword(s):  
Solar System ◽  
Planetary System ◽  
Large Fraction ◽  
Planetary Systems ◽  
Single Star ◽  
Solar Systems ◽  
Close Encounters ◽  
Eccentric Orbits ◽  
The Galaxy ◽  
Hostile Environments

AbstractMany stars are formed in some form of cluster or association. These environments can have a much higher number density of stars than the field of the galaxy. Such crowded places are hostile environments: a large fraction of initially single stars will undergo close encounters with other stars or exchange into binaries. We describe how such close encounters and exchange encounters will affect the properties of a planetary system around a single star. We define singletons as single stars which have never suffered close encounters with other stars or spent time within a binary system. It may be that planetary systems similar to our own solar system can only survive around singletons. Close encounters or the presence of a stellar companion will perturb the planetary system, leading to strong planet-planet interactions, often leaving planets on tighter and more eccentric orbits. Thus, planetary systems which initially resembled our own solar system may later more closely resemble the observed extrasolar planetary systems.

scholarly journals SOPHIE velocimetry of Kepler transit candidates

2018 ◽  
Vol 615 ◽  
pp. A90 ◽  
Author(s):  
J. M. Almenara ◽  
R. F. Díaz ◽  
G. Hébrard ◽  
R. Mardling ◽  
C. Damiani ◽  
...  
Keyword(s):  
Planetary System ◽  
Major Axis ◽  
Giant Planets ◽  
Eccentric Orbit ◽  
Semi Major Axis ◽  
Hot Jupiters ◽  
Timing Data ◽  
Single Host ◽  
Velocity Information ◽  
The Masses

Kepler-419 is a planetary system discovered by the Kepler photometry which is known to harbour two massive giant planets: an inner 3 MJ transiting planet with a 69.8-day period, highly eccentric orbit, and an outer 7.5 MJ non-transiting planet predicted from the transit-timing variations (TTVs) of the inner planet b to have a 675-day period, moderately eccentric orbit. Here we present new radial velocity (RV) measurements secured over more than two years with the SOPHIE spectrograph, where both planets are clearly detected. The RV data is modelled together with the Kepler photometry using a photodynamical model. The inclusion of velocity information breaks the MR−3 degeneracy inherent in timing data alone, allowing us to measure the absolute stellar and planetary radii and masses. With uncertainties of 12 and 13% for the stellar and inner planet radii, and 35, 24, and 35% for the masses of the star, planet b, and planet c, respectively, these measurements are the most precise to date for a single host star system using this technique. The transiting planet mass is determined at better precision than the star mass. This shows that modelling the radial velocities and the light curve together in systems of dynamically interacting planets provides a way of characterising both the star and the planets without being limited by knowledge of the star. On the other hand, the period ratio and eccentricities place the Kepler-419 system in a sweet spot; had around twice as many transits been observed, the mass of the transiting planet could have been measured using its own TTVs. Finally, the origin of the Kepler-419 system is discussed. We show that the system is near a coplanar high-eccentricity secular fixed point, related to the alignment of the orbits, which has prevented the inner orbit from circularising. For most other relative apsidal orientations, planet b’s orbit would be circular with a semi-major axis of 0.03 au. This suggests a mechanism for forming hot Jupiters in multiplanetary systems without the need of high mutual inclinations.

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