Formation of Terrestrial Planets

Izidoro, André; Raymond, Sean N.

doi:10.1007/978-3-319-30648-3_142-1

Cited by 8 publications

(12 citation statements)

References 474 publications

(568 reference statements)

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“…The remnant planetesimal populations in the solar system nevertheless provide us with a possibility of probing the properties of the primordial planetesimals that formed around the young Sun. Terrestrial planet formation simulations successfully form Earth and Venus analogues starting from protoplanets with a total mass of a few M E (Raymond et al, 2009;Izidoro, & Raymond, 2018), more than an order of magnitude lower than the above scenario of a very massive planetesimal population would predict. Adding more mass than this to the terrestrial planet zone instead results in the formation of a population of migrating super-Earths (Ogihara et al, 2015).…”

Section: Introductionmentioning

confidence: 85%

Exploring the conditions for forming cold gas giants through planetesimal accretion

Johansen¹,

Bitsch²

2019

A&A

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The formation of cold gas giants similar to Jupiter and Saturn in orbit and mass is a great challenge for planetesimal-driven core accretion models because the core growth rates far from the star are low. Here we model the growth and migration of single protoplanets that accrete planetesimals and gas. We integrated the core growth rate using fits in the literature to N-body simulations, which provide the efficiency of accreting the planetesimals that a protoplanet migrates through. We take into account three constraints from the solar system and from protoplanetary discs: (1) the masses of the terrestrial planets and the comet reservoirs in Neptune's scattered disc and the Oort cloud are consistent with a primordial planetesimal population of a few Earth masses per AU, (2) evidence from the asteroid belt and the Kuiper belt indicates that the characteristic planetesimal diameter is 100 km, and (3) observations of protoplanetary discs indicate that the dust is stirred by weak turbulence; this gas turbulence also excites the inclinations of planetesimals. Our nominal model built on these constraints results in maximum protoplanet masses of 0.1 Earth masses. Ignoring constraint (1) above, we show that even a planetesimal population of 1,000 Earth masses, corresponding to 50 Earth masses per AU, fails to produce cold gas giants (although it successfully forms hot and warm gas giants). We conclude that a massive planetesimal reservoir is in itself insufficient to produce cold gas giants. The formation of cold gas giants by planetesimal accretion additionally requires that planetesimals are small and that the turbulent stirring is very weak, thereby violating all three above constraints.

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Section: Introductionmentioning

confidence: 85%

Exploring the conditions for forming cold gas giants through planetesimal accretion

Johansen¹,

Bitsch²

2019

A&A

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“…To date, more than 4000 exoplanets have been detected. Statistics of their orbital parameters (Santos 2008;Santos & Faria 2018) put constraints on the models that explain the formation of planets (Raymond et al 2014;Izidoro & Raymond 2018;Santos et al 2017;D'Angelo & Lissauer 2018;Adibekyan 2019). To put more constraints on these models, we require detections of exoplanets that orbit in the outer part of their system, close to the ice-line.…”

Section: Introductionmentioning

confidence: 99%

A family of phase masks for broadband coronagraphy example of the wrapped vortex phase mask theory and laboratory demonstration

Galicher

Baudoz

Huby

et al. 2020

A&A

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Context. Future instruments need efficient coronagraphs over large spectral ranges to enable broadband imaging or spectral characterization of exoplanets that are 10 8 times fainter than their star. Several solutions have been proposed. Pupil apodizers can attenuate the star intensity by a factor of 10 10 but they only transmit a few percent of the light of the planet. Cascades of phase and/or amplitude masks can both attenuate the starlight and transmit most of the planet light, but the number of optics that require alignment makes this solution impractical for an instrument. Finally, vector phase masks can be used to detect faint sources close to bright stars but they require the use of high-quality circular polarizers and, as in the previous solution, this leads to a complex instrument with numerous optics that require alignment and stabilization. Aims. We propose simple coronagraphs that only need one scalar phase mask and one binary Lyot stop providing high transmission for the planet light (> 50 %) and high attenuation of the starlight over a large spectral bandpass (∼ 30 %) and a 360 • field-of-view. Methods. From mathematical considerations, we find a family of 2D phase masks optimized for an unobscured pupil. One mask is an azimuthal wrapped vortex phase ramp. We probe its coronagraphic performance using numerical simulations and laboratory tests. Results. From numerical simulations, we predict the wrapped vortex can attenuate the peak of the star image by a factor of 10 4 over a 29 % bandpass and 10 5 over a 18 % bandpass with transmission of more than 50 % of the planet flux at ∼ 4 λ/D. We confirm these predictions in the laboratory in visible light between 550 and 870 nm. We also obtain laboratory dark hole images in which exoplanets with fluxes that are 3.10 −8 times the host star flux could be detected at 3 σ. Conclusions. Taking advantage of a new technology for etching continuous 2D functions, a new type of mask can be easily manufactured opening up new possibilities for broadband coronagraphy.

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“…Ppα Determining the average planet mass is somewhat involved, given the many distinct stages of growth that occur as microscopic dust grains agglomerate to the size of planets. For reviews of this multi-stage process, see [59][60][61]. In brief, planetesimals form characteristic masses as the final outcome of pebble (or dust) accretion.…”

Section: Choicesmentioning

confidence: 99%

Multiverse Predictions for Habitability: Number of Potentially Habitable Planets

Sandora

2019

Universe

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How good is our universe at making habitable planets? The answer to this depends on which factors are important for life: Does a planet need to be Earth mass? Does it need to be inside the temperate zone? are systems with hot Jupiters habitable? Here, we adopt different stances on the importance of each of these criteria to determine their effects on the probabilities of measuring the observed values of several physical constants. We find that the presence of planets is a generic feature throughout the multiverse, and for the most part conditioning on their particular properties does not alter our conclusions much. We find conflict with multiverse expectations if planetary size is important and it is found to be uncorrelated with stellar mass, or the mass distribution is too steep. The existence of a temperate circumstellar zone places tight lower bounds on the fine structure constant and electron to proton mass ratio.

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Formation of Terrestrial Planets

Cited by 8 publications

References 474 publications

Exploring the conditions for forming cold gas giants through planetesimal accretion

Exploring the conditions for forming cold gas giants through planetesimal accretion

A family of phase masks for broadband coronagraphy example of the wrapped vortex phase mask theory and laboratory demonstration

Multiverse Predictions for Habitability: Number of Potentially Habitable Planets

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