scholarly journals Formation of heavy element rich giant planets by giant impacts

2007 ◽  
Vol 3 (S249) ◽  
pp. 267-270
Author(s):  
H. Genda ◽  
M. Ikoma ◽  
T. Guillot ◽  
S. Ida
Keyword(s):  
Total Mass ◽  
Heavy Element ◽  
Theoretical Models ◽  
Impact Angle ◽  
Giant Planets ◽  
Hot Jupiters ◽  
Smoothed Particle ◽  
Giant Impacts ◽  
Gas Giant ◽  
Smoothed Particle Hydrodynamic

AbstractWe have performed the smoothed particle hydrodynamic (SPH) simulations of collisions between two gas giant planets. Changes in masses of the ice/rock core and the H/He envelope due to the collisions are investigated. The main aim of this study is to constrain the origin and probability of a class of extrasolar hot Jupiters that have much larger cores and/or higher core/envelope mass ratios than those predicted by theories of accretion of gas giant planets. A typical example is HD 149026b. Theoretical models of the interior of HD 149026b (Sato et al. 2005; Fortney et al. 2006; Ikoma et al. 2006) predict that the planet contains a huge core of 50-80 Earth masses relative to the total mass of 110 Earth masses. Our SPH simulations demonstrate that such a gas giant is produced by a collision with an impact velocity of typically more than 2.5 times escape velocity and an impact angle of typically less than 10 degrees, which results in an enormous loss of the envelope gas and complete accretion of both cores.

scholarly journals Planetary embryo collisions and the wiggly nature of extreme debris discs

2021 ◽  
Vol 502 (2) ◽  
pp. 2984-3002
Author(s):  
Lewis Watt ◽  
Zoe Leinhardt ◽  
Kate Y L Su
Keyword(s):  
Equations Of State ◽  
Semimajor Axis ◽  
Central Star ◽  
Impact Angle ◽  
Narrow Region ◽  
Term Variation ◽  
Planetary Embryo ◽  
Smoothed Particle ◽  
Giant Impacts ◽  
Post Impact

ABSTRACT In this paper, we present results from a multistage numerical campaign to begin to explain and determine why extreme debris disc detections are rare, what types of impacts will result in extreme debris discs and what we can learn about the parameters of the collision from the extreme debris discs. We begin by simulating many giant impacts using a smoothed particle hydrodynamical code with tabulated equations of state and track the escaping vapour from the collision. Using an N-body code, we simulate the spatial evolution of the vapour generated dust post-impact. We show that impacts release vapour anisotropically not isotropically as has been assumed previously and that the distribution of the resulting generated dust is dependent on the mass ratio and impact angle of the collision. In addition, we show that the anisotropic distribution of post-collision dust can cause the formation or lack of formation of the short-term variation in flux depending on the orientation of the collision with respect to the orbit around the central star. Finally, our results suggest that there is a narrow region of semimajor axis where a vapour generated disc would be observable for any significant amount of time implying that giant impacts where most of the escaping mass is in vapour would not be observed often but this does not mean that the collisions are not occurring.

scholarly journals Investigating the planet–metallicity correlation for hot Jupiters

2019 ◽  
Vol 491 (3) ◽  
pp. 4481-4487
Author(s):  
Ares Osborn ◽  
Daniel Bayliss
Keyword(s):  
Radial Velocity ◽  
Giant Planet ◽  
Giant Planets ◽  
Similar Process ◽  
Wide Field ◽  
Hot Jupiters ◽  
Galaxy Model ◽  
Gas Giant ◽  
Correlation Consistent

ABSTRACT We investigate the giant planet–metallicity correlation for a homogeneous, unbiased set of 217 hot Jupiters taken from nearly 15 yr of wide-field ground-based surveys. We compare the host star metallicity to that of field stars using the Besançon Galaxy model, allowing for a metallicity measurement offset between the two sets. We find that hot Jupiters preferentially orbit metal-rich stars. However, we find the correlation consistent, though marginally weaker, for hot Jupiters ($\beta =0.71^{+0.56}_{-0.34}$) than it is for other longer period gas giant planets from radial velocity surveys. This suggests that the population of hot Jupiters probably formed in a similar process to other gas giant planets, and differ only in their migration histories.

scholarly journals FRIENDS OF HOT JUPITERS. I. A RADIAL VELOCITY SEARCH FOR MASSIVE, LONG-PERIOD COMPANIONS TO CLOSE-IN GAS GIANT PLANETS

2014 ◽  
Vol 785 (2) ◽  
pp. 126 ◽  
Author(s):  
Heather A. Knutson ◽  
Benjamin J. Fulton ◽  
Benjamin T. Montet ◽  
Melodie Kao ◽  
Henry Ngo ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Giant Planets ◽  
Hot Jupiters ◽  
Long Period ◽  
Gas Giant

scholarly journals NGTS-6b: an ultrashort period hot-Jupiter orbiting an old K dwarf

2019 ◽  
Vol 489 (3) ◽  
pp. 4125-4134 ◽  
Author(s):  
Jose I Vines ◽  
James S Jenkins ◽  
Jack S Acton ◽  
Joshua Briegal ◽  
Daniel Bayliss ◽  
...  
Keyword(s):  
Bulk Density ◽  
Small Population ◽  
Giant Planets ◽  
Gaseous Atmosphere ◽  
Next Generation ◽  
Evolutionary Mechanisms ◽  
Hot Jupiters ◽  
Gas Giant ◽  
Hot Jupiter

ABSTRACT We report the discovery of a new ultrashort period hot Jupiter from the Next Generation Transit Survey. NGTS-6b orbits its star with a period of 21.17 h, and has a mass and radius of $1.330^{+0.024}_{-0.028}$MJ and $1.271^{+0.197}_{-0.188}$RJ, respectively, returning a planetary bulk density of $0.711^{+0.214}_{-0.136}$ g cm−3. Conforming to the currently known small population of ultrashort period hot Jupiters, the planet appears to orbit a metal-rich star ([Fe/H] = +0.11 ± 0.09 dex). Photoevaporation models suggest the planet should have lost 5 per cent of its gaseous atmosphere over the course of the 9.6 Gyr of evolution of the system. NGTS-6b adds to the small, but growing list of ultrashort period gas giant planets, and will help us to understand the dominant formation and evolutionary mechanisms that govern this population.

scholarly journals How planet–planet scattering can create high-inclination as well as long-period orbits

2010 ◽  
Vol 6 (S276) ◽  
pp. 225-229 ◽  
Author(s):  
Sourav Chatterjee ◽  
Eric B. Ford ◽  
Frederic A. Rasio
Keyword(s):  
Major Axis ◽  
Theoretical Models ◽  
Giant Planets ◽  
Direct Imaging ◽  
Semi Major Axis ◽  
Hot Jupiters ◽  
Long Period ◽  
Outer Disk ◽  
Planetary Orbits ◽  
Core Accretion

AbstractRecent observations have revealed two new classes of planetary orbits. Rossiter-Mclaughlin (RM) measurements have revealed hot Jupiters in high-obliquity orbits. In addition, direct-imaging has discovered giant planets at large (~ 100 AU) separations via direct-imaging technique. Simple-minded disk-migration scenarios are inconsistent with the high-inclination (and even retrograde) orbits as seen in recent RM measurements. Furthermore, forming giant planets at large semi-major axis (a) may be challenging in the core-accretion paradigm. We perform many N-body simulations to explore the two above-mentioned orbital architectures. Planet–planet scattering in a multi-planet system can naturally excite orbital inclinations. Planets can also get scattered to large distances. Large-a planetary orbits created from planet–planet scattering are expected to have high eccentricities (e). Theoretical models predict that the observed long-period planets, such as Fomalhaut-b have moderate e ≈ 0.3. Interestingly, these are also in systems with disks. We find that if a massive-enough outer disk is present, a scattered planet may be circularized at large a via dynamical friction from the disk and repeated scattering of the disk particles.

scholarly journals Chemical fingerprints of hot Jupiter planet formation

2018 ◽  
Vol 612 ◽  
pp. A93 ◽  
Author(s):  
J. Maldonado ◽  
E. Villaver ◽  
C. Eiroa
Keyword(s):  
Planet Formation ◽  
Statistical Tests ◽  
Giant Planets ◽  
Volatile Elements ◽  
Hot Jupiters ◽  
Chemical Fingerprints ◽  
Gas Giant ◽  
Orbital Periods ◽  
And Migration

Context. The current paradigm to explain the presence of Jupiter-like planets with small orbital periods (P < 10 days; hot Jupiters), which involves their formation beyond the snow line following inward migration, has been challenged by recent works that explore the possibility of in situ formation. Aims. We aim to test whether stars harbouring hot Jupiters and stars with more distant gas-giant planets show any chemical peculiarity that could be related to different formation processes. Methods. Our methodology is based on the analysis of high-resolution échelle spectra. Stellar parameters and abundances of C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, and Zn for a sample of 88 planet hosts are derived. The sample is divided into stars hosting hot (a < 0.1 au) and cool (a > 0.1 au) Jupiter-like planets. The metallicity and abundance trends of the two sub-samples are compared and set in the context of current models of planet formation and migration. Results. Our results show that stars with hot Jupiters have higher metallicities than stars with cool distant gas-giant planets in the metallicity range +0.00/+0.20 dex. The data also shows a tendency of stars with cool Jupiters to show larger abundances of α elements. No abundance differences between stars with cool and hot Jupiters are found when considering iron peak, volatile elements or the C/O, and Mg/Si ratios. The corresponding p-values from the statistical tests comparing the cumulative distributions of cool and hot planet hosts are 0.20, <0.01, 0.81, and 0.16 for metallicity, α, iron-peak, and volatile elements, respectively. We confirm previous works suggesting that more distant planets show higher planetary masses as well as larger eccentricities. We note differences in age and spectral type between the hot and cool planet host samples that might affect the abundance comparison. Conclusions. The differences in the distribution of planetary mass, period, eccentricity, and stellar host metallicity suggest a different formation mechanism for hot and cool Jupiters. The slightly larger α abundances found in stars harbouring cool Jupiters might compensate their lower metallicities allowing the formation of gas-giant planets.

scholarly journals The diverse origin of exoplanets' eccentricities & inclinations

2010 ◽  
Vol 6 (S276) ◽  
pp. 221-224
Author(s):  
Eric B. Ford
Keyword(s):  
Rotation Axis ◽  
Orbital Evolution ◽  
Giant Planets ◽  
Direct Imaging ◽  
Wide Binary ◽  
Hot Jupiters ◽  
Short Period ◽  
New Type ◽  
Low Mass ◽  
Diverse Origin

AbstractRadial velocity surveys have discovered over 400 exoplanets. While measuring eccentricities of low-mass planets remains a challenge, giant exoplanets display a broad range of orbital eccentricities. Recently, spectroscopic measurements during transit have demonstrated that the short-period giant planets (“hot-Jupiters”) also display a broad range of orbital inclinations (relative to the rotation axis of the host star). Both properties pose a challenge for simple disk migration models and suggest that late-stage orbital evolution can play an important role in determining the final architecture of planetary systems. One possible formation mechanism for the inclined hot-Jupiters is some form of eccentricity excitation (e.g., planet scattering, secular perturbations due to a distant planet or wide binary) followed tidal circularization. The planet scattering hypothesis also makes predictions for the population of planets at large separations. Recent discoveries of planets on wide orbits via direct imaging and highly anticipated results from upcoming direct imaging campaigns are poised to provide a new type of constraint on planet formation. This proceedings describes recent progress in understanding the formation of giant exoplanets.

scholarly journals Rapid Formation of Gas-giant Planets via Collisional Coagulation from Dust Grains to Planetary Cores

2021 ◽  
Vol 922 (1) ◽  
pp. 16
Author(s):  
Hiroshi Kobayashi ◽  
Hidekazu Tanaka
Keyword(s):  
Protoplanetary Disks ◽  
Central Star ◽  
Giant Planets ◽  
Solar Systems ◽  
Evolution Path ◽  
Planetary Cores ◽  
Rapid Formation ◽  
Gas Giant ◽  
Planetary Migration ◽  
Gas Accretion

Abstract Gas-giant planets, such as Jupiter, Saturn, and massive exoplanets, were formed via the gas accretion onto the solid cores, each with a mass of roughly 10 Earth masses. However, rapid radial migration due to disk–planet interaction prevents the formation of such massive cores via planetesimal accretion. Comparably rapid core growth via pebble accretion requires very massive protoplanetary disks because most pebbles fall into the central star. Although planetesimal formation, planetary migration, and gas-giant core formation have been studied with a lot of effort, the full evolution path from dust to planets is still uncertain. Here we report the result of full simulations for collisional evolution from dust to planets in a whole disk. Dust growth with realistic porosity allows the formation of icy planetesimals in the inner disk (≲10 au), while pebbles formed in the outer disk drift to the inner disk and there grow to planetesimals. The growth of those pebbles to planetesimals suppresses their radial drift and supplies small planetesimals sustainably in the vicinity of cores. This enables rapid formation of sufficiently massive planetary cores within 0.2–0.4 million years, prior to the planetary migration. Our models shows the first gas giants form at 2–7 au in rather common protoplanetary disks, in agreement with the exoplanet and solar systems.

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