Centro de Astrobiología (CAB, CSIC-INTA) is offering 1 PhD position within the María de Maeztu Excellence Program «Assesing the feasibility of life as a universal phenomenon through planetary exploration», as part of the Aids for pre-doc contracts for the training of doctors 2021
Title : COMETARY IMPACTS AND THE BUILDING OF PLANETARY ATMOSPHERES
Description of the project
The main goal of this project is: i) to study the effect of potential cometary/asteroid impacts on planets, ii) how the impacts would affect the primordial atmospheres of these planets if they exist, and iii) their potential to re-build them with a view to assessing whether any sort of life has a chance to develop. The project is general enough that have potential impact on planetary and astrobiology research areas while using the tools we have developed over the years on the study of planetary systems around evolved stars, giants and white dwarfs.
Some planets are larger than predicted requiring a source of additional heating, but some are surprisingly small needing to accumulate metallicity and large cores. For this thesis project we will explore first the process of accretion of rocky bodies onto giant planets. If the rocky debris remains in the outer envelope and enrich the atmosphere it can increase the metallicity and explain the small radius but if it travels to the core could provide a long term source of heating. We will calculate collision rates and the distribution of impact velocities and with numerical simulations we will study the deposition of the kinetic energy onto the planet.
For the study of the formation of planetary atmospheres, we will consider rocky planets and both atmospheric mass loss and volatile delivery. The orbital evolution of potential impacting comets/asteroids will be studied using N-body simulations. We will investigate potential impacting bodies to determine which planets are more likely to be impacted and the distributions of impact velocities. We will consider all the scenarios that could throw comets/asteroids into the inner region from an outer belt (Kuiper belt or an Oort cloud): planet scattering, the Kozai-Lidov and Galactic tides. The solution of the problem will require to determine the mass of volatiles that can be delivered, if high velocity impacts can destroy primordial atmospheres and which ones and at which distances can also easily be replenished with cometary volatiles (i.e. an Earth ocean mass of water).
A PhD thesis, referred papers, presentation of results in conferences, outreach and a deeper understanding on these topics: i) the unusual radius observed for giant planets that can be confronted with observations, ii) an assessment of the impact that small bodies (asteroids and comets) may have in the chemical building of the planetary atmospheres of rocky planets, iii) a quantification on the relative importance of the different mechanisms capable of efficiently deliver small bodies into planetary bodies: planet scattering, Kozai-Lidov and Galactic tides, iv) an assessment on the importance of planetary impacts on building a planetary mass of water.
National Plan/European/CAM associated projects: PGC2018-101950-B-I00
Expected synergies between lines
Asteroids and comets, i.e. small bodies play a fundamental role from the Solar System formation to the building of planets and planetary atmospheres of exoplanets. We will explore their influence on planetary evolution and chemistry by studying the evolution of their impact on planet surfaces and the mechanisms by which they take place. The process has influence in astrobiology processes from water delivery, to atmospheric composition, planetary surfaces and planet evolution.
Location: CAB ESAC (Villafranca del Castillo – Madrid)
More information on the project:: Eva Villaver firstname.lastname@example.org
The deadline for submission of applications is 28 October to 11 November 2021 at 14:00 hours (Spanish peninsular time).
Call and applications: