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Johansen, Jens Brock; Théoret, Raymond; Christopherson, Robert; Rouah, Fabrice Douglas; Meier, Iwan; Wendt, Stefan; Gatfaoui, Hayette; Ci̇van, Abdülkadi̇r; Freihammer, John; Gaspar, Raquel M.; Stolpe, Julia; Powell, Don W.; Kırkulak, Berna; Hübner, Georges; Rehan, Christine; Olboeter, Sven; Read, Colin; Gueyié, Jean‐Pierre; Ding, Bill; Füss, Roland; Gorham, Michael; Menyah, Kojo; Dolvin, Steven D.; Proelss, Juliane; Secrieru, Oana; Rockey, Joan; Koh, Winston T. H.; Ulreich, Stefan; Schmidt, Daniel; Gounopoulos, Dimitrios; Adams, Zeno; Kaserer, Christoph; Solakoglu, Nihat; Borell, Mariela; Pietsch, Robert

doi:10.1201/9781420064896.ch16

Cited by 43 publications

(50 citation statements)

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“…For our planet formation model we follow the core accretion scenario where planetary cores grow by pebble accretion (Ormel & Klahr 2010;Johansen & Lacerda 2010;Lambrechts & Johansen 2012) and migrate through type-I migration using the prescription of Paardekooper et al (2011). We use the disc model outlined in Bitsch et al (2015a), where we either let the disc evolve in time or not to illustrate its influence on planetary composition similar to the principles outlined in Bitsch et al (2019b).…”

Section: Appendix C: Planet Formationmentioning

confidence: 99%

Influence of sub- and super-solar metallicities on the composition of solid planetary building blocks

Bitsch

Battistini

2019

A&A

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The composition of the protoplanetary disc is thought to be linked to the composition of the host star, where a higher overall metallicity of the host star provides more building blocks for planets. However, most of the planet formation simulations only link the stellar iron abundance [Fe/H] to planet formation and the iron abundance in itself is used as a proxy to scale all elements. On the other hand, large surveys of stellar abundances show that this is not true. We use here stellar abundances from the GALAH surveys to determine the average detailed abundances of Fe, Si, Mg, O, and C for a broad range of host star metallicities with [Fe/H] spanning from -0.4 to +0.4. Using an equilibrium chemical model that features the most important rock forming molecules as well as volatile contributions of H 2 O, CO 2 , CH 4 and CO, we calculate the chemical composition of solid planetary building blocks around stars with different metallicities. Solid building blocks that are formed entirely interior to the water ice line (T>150K) only show an increase in Mg 2 SiO 4 and a decrease in MgSiO 3 for increasing host star metallicity, related to the increase of Mg/Si for higher [Fe/H]. Solid planetary building blocks forming exterior to the water ice line (T<150K), on the other hand, show dramatic changes in their composition. In particular the water ice content decreases from around ∼50% at [Fe/H]=-0.4 to ∼6% at [Fe/H]=0.4 in our chemical model. This is mainly caused by the increasing C/O ratio with increasing [Fe/H], which binds most of the oxygen in gaseous CO and CO 2 , resulting in a small water ice fraction. Planet formation simulations coupled with the chemical model confirm these results by showing that the water ice content of super-Earths decreases with increasing host star metallicity due to the increased C/O ratio. This decrease of the water ice fraction has important consequences for planet formation, planetary composition and the eventual habitability of planetary systems formed around these high metallicity stars.

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Section: Appendix C: Planet Formationmentioning

confidence: 99%

Influence of sub- and super-solar metallicities on the composition of solid planetary building blocks

Bitsch

Battistini

2019

A&A

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“…Dodson- Robinson et al 2009;Rafikov 2011). The so-called pebble accretion mechanism (in which small particles with sizes ranging from millimetres to centimetres constitute the main drivers of planetary growth) has been shown to accelerate the growth speed of planetary cores (Johansen & Lacerda 2010;Ormel & Klahr 2010; A&A proofs: manuscript no. 32001_corr Lambrechts & Johansen 2012Johansen & Lambrechts 2017).…”

Section: Introductionmentioning

confidence: 99%

Chemical fingerprints of hot Jupiter planet formation

Maldonado

Villaver

Eiroa

2018

A&A

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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.

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“…Rotation of a small body is set by planetesimal formation processes (Johansen & Lacerda 2010, Visser et al 2020, and evolves by impacts (Farinella et al 1992) and radiation effects such as YORP (Vokrouhlický et al 2003). Formation processes and impacts are expected to yield the Maxwellian distribution (e.g., Medeiros et al 2018) with predominantly fast spins.…”

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confidence: 99%

Very Slow Rotators from Tidally Synchronized Binaries

Nesvorný

Vokrouhlický

Bottke

et al. 2020

ApJL

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A recent examination of K2 lightcurves indicates that ∼15% of Jupiter Trojans have very slow rotation (spin periods P s > 100 h). Here we consider the possibility that these bodies formed as equal-size binaries in the massive outer disk at ∼20-30 au. Prior to their implantation as Jupiter Trojans, tight binaries tidally evolved toward a synchronous state with P s ∼ P b , where P b is the binary orbit period. They may have been subsequently dissociated by impacts and planetary encounters with at least one binary component retaining its slow rotation. Surviving binaries on Trojan orbits would continue to evolve by tides and spin-changing impacts over 4.5 Gyr. To explain the observed fraction of slow rotators, we find that at least ∼15-20% of outer disk bodies with diameters 15 < D < 50 km would have to form as equal-size binaries with 12 a b /R 30, where a b is the binary semimajor axis and R = D/2. The mechanism proposed here could also explain very slow rotators found in other small body populations.

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Cited by 43 publications

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Influence of sub- and super-solar metallicities on the composition of solid planetary building blocks

Influence of sub- and super-solar metallicities on the composition of solid planetary building blocks

Chemical fingerprints of hot Jupiter planet formation

Very Slow Rotators from Tidally Synchronized Binaries

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