Institute of Astronomy

- Chiara Scardoni

E-mail: ces204@ast.cam.ac.uk

Office: Obs O13
Office Tel: (01223) 337525
More Info (Internal)

Preprints
Publications

Research Themes: Star Formation and Exoplanets

Research Keywords: Accretion, Planets, Star-formation

Research

My research focuses on the study of protoplanetary discs, with a particular interest in planet-disc interaction and dust-gas interaction. Protoplanetary discs are disc-shaped structures that form during the process of star formation; they are made of dust and gas (in a typical dust to gas mass ratio of the order of 1:100) and are thought to be the planets' birthplaces. In this context, I am focusing on the following aspects:

  • Discs' viscous evolution and its consequences on the discs' distribution in the M-Mdot plane. Protoplanetary discs' material moves inward and accrete on to the central star, thanks to the re-distribution of angular momentum within the disc. During the disc lifetime, its mass is therefore expected to change, as well as the properties of accretion onto the star. In this work, I focused on characterising the properties of the mass (M) and the accretion rate (Mdot) during the disc evolution, under the simplifying assumption that the discs evolve viscously (using the self-similar evolution model). I then imlemented population synthesis model to compare the theoretical findings to the M-Mdot distribution in the Lupus star forming region.
    [Protoplanetary disc `isochrones' and the evolution of discs in the Ṁ-M_d plane (2017) Lodato, G.; Scardoni, C. E.; Manara, C. F.; Testi, L.]
     
  • The role of streaming instability in solving the radial drift barrier to planetesimal formation. The radial drift barrier is a well-known problem in the process of solid planet formaiton thorugh core accretion (according to which planets form dust growth from the initial μm-sized dust grains to the size of a planet). When the grains reach the cm-size, in fact, their interaction with the disc gas component determines their rapid drift towards the central star, preventing them to grow more and form planets. Streaming instability is a potential solution to this problem because, under appropriate conditions, it promotes fast particle clumping and planetesimal (~km-sized) formation. In this context, I simulated systems undergoing streaming instability and applied a radiative transfer model to study their mm-emission. By focusing on 2 observable quantities (the optically thick fraction and the spectral index), I compared the obtained theoretical distribution to the available observations in the Lupus star forming region, showing that the current observations are consistent with the hypothesis of clump formation via streaming instaiblity.
    [The effect of the streaming instability on protoplanetary disc emission at millimetre wavelengths (2021) Scardoni, C. E.; Booth, R. A.; Clarke, C. J.]
     
  • The role of planet migration in explaining the exoplanetary systems' architecture. The interaction between a planet and the host disc determines an exchange of angular momentum between the two, causing on one hand a modification of the planet's orbital parameter, and on the other hand a change of the disc's structure. As a result of this interaction, planets are expected to migrate, changing their semi-major axis (and potentially their eccentricity). I am focusing on the "Type II" mgiration regime, which is relevant for planetes massive enoguh to open a gap in the disc surface density. Depending on the disc to planet mass ratio, this migration regime can be disc-dominated (where the disc is expeced to migrate at the disc's viscous timescale) or planet-dominated (which is expected to be slower, due to the planet's significant inertia). In this context, I am performing long term hydrodynamical simulations in both the migration regimes, in order to study planet migration (whose timescales are still under debate); through these works I am contributing to improve planet migration models, which are essential to estimate the final location of planets after disc dispersal, and thus to understand the observed architecture of exoplanetary systems.
    [Type II migration strikes back - an old paradigm for planet migration in discs (2020) Scardoni, C. E.; Rosotti, G. P.; Lodato, G.; Clarke, C. J.]

Selected papers

The effect of the streaming instability on protoplanetary disc emission at millimetre wavelengths (2021) Scardoni, C. E.; Booth, R. A.; Clarke, C. J.

X-shooter survey of disk accretion in Upper Scorpius. I. Very high accretion rates at age > 5 Myr (2020) Manara, C. F.; Natta, A.; Rosotti, G. P.; Alcala, J. M.; Nisini, B.; Lodato, G.; Testi, L.; Pascucci,I.; Hillenbrand, L.; Carpenter, J.; Scholz, A.; Fedele, D.; Frasca, A.; Mulders, G.; Rigliaco, E.; Scardoni, C.; Zari, E.

Type II migration strikes back - an old paradigm for planet migration in discs (2020) Scardoni, C. E.; Rosotti, G. P.; Lodato, G.; Clarke, C. J.

Protoplanetary disc `isochrones' and the evolution of discs in the Ṁ-M_d plane (2017) Lodato, G.; Scardoni, C. E.; Manara, C. F.; Testi, L.

Career

2019-present: PhD student in Astronomy; supervisors: Professor Cathie Clarke, Dr Marco Tazzari

2017–2019: Master’s Degree in Physics (University of Milan)

2013–2017: Bachelor’s Degree in Physics (University of Milan)
 

Page last updated: 31 March 2022 at 11:51