title: The post-formation entropy of gas giants: Radiative properties of the accretion shock and constraints from observations
creator: Marleau, Gabriel-Dominique
subject: ddc-520
subject: 520 Astronomy and allied sciences
description: We study the radiative properties and in particular the radiation loss efficiency of the planetary accretion shock by performing radiation-hydrodynamics simulations of accretion onto a planet at snapshots during its formation. We use the state-of-the-art code PLUTO in spherical symmetry and both one- and two-temperature flux limited diffusion. We take tabulated gas and dust opacities and use a constant equation of state to isolate radiation transport effects.    We find that, for a significant subset of the formation parameter space, the schock is isothermal and essentially the entire kinetic energy is converted to radiation. The fraction brought into the planet is negligible compared to the internal luminosity, which appears to favour the so-called ‘cold-start’ assumption.    We also study what constraints direct detections can provide on the post-formation entropy. First, we attempt to produce accurate cooling tracks by using self-consistently the sophisticated BT-Settl-2010 atmospheric models. However, we find that this is not possible because of due to dust phase transitions at Teff ≈ 1500 K. Secondly, we set lower bounds on the post-formation entropy of some well-studied gas giants. We find that they most likely did not form as classical coldest starts, but that κ Andromeda b may be undergoing a ‘deuterium flash’.
date: 2016
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/20295/1/Doktorarbeit_Uni.pdf
identifier: DOI:10.11588/heidok.00020295
identifier: urn:nbn:de:bsz:16-heidok-202955
identifier:   Marleau, Gabriel-Dominique  (2016) The post-formation entropy of gas giants: Radiative properties of the accretion shock and constraints from observations.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/20295/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng