Nicolás Cuello
Researcher in Astrophysics
Marie Curie fellow
IPAG – Grenoble – France
Project |01
PLANET FORMATION IN MULTIPLE SYSTEMS: CIRCUMBINARY DISCS, POLAR ALIGNMENT & TATOOINES
Project |02
STELLAR FLYBYS: THEORY, SIMULATIONS & OBSERVATIONS
Stellar multiplicity is ubiquitous in regions of star formation. In other words, young stellar objects often born in multiple stellar systems. When two stars are bound, we talk about a binary. The disc around two stars is called circumbinary, and it is also possible to have circumstellar discs around each star. In the series of works below, we explored the effects of the binary on disc structure and evolution. In particular, we consistently connected our simulations with multi-wavelength observations of protoplanetary discs such as HD142527, IRS 48, and AB Aur.
D.J. Price, N. Cuello, C. Pinte et al. – MNRAS (2018)
P.P. Poblete, N. Cuello, J. Cuadra – MNRAS (2019)
J. Calcino, D.J. Price, C. Pinte et al. – MNRAS (2019)
P.P. Poblete, J. Calcino, N. Cuello et al. – MNRAS (2020)
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How do misaligned circumbinary discs evolve over time? There are two stable configurations: coplanar and polar (i.e. binary and disc orthogonal to each other). Here we found that polar circumbinary discs could be more common than previously thought because of non-linear effects. Then, assuming planet formation occurs in these discs, how stable are these polar circumbinary planets (aka polar Tatooines)? These are stable over a wide range of binary parameters, in particular for low binary eccentricities (e<0.4). We suggest that mildly eccentric equal-mass binaries are the most promising targets in the sky to look for the first Polar Tatooine.
Planet formation does not occur in isolation. Hence, stellar encounters are expected to occur during the early stages of star and planet formation. But, how does a stellar flyby perturb a protoplanetary disc? In particular, what is the response of the dust to the tidal encounter? We answer these questions in this work. Gas and dust structures induced by the flyby differ because of drag-induced effects on the dust grains. The remnant discs are truncated and warped. These effects strongly depend on the perturber's orbital parameters. Interestingly, for prograde encounters, the accretion rate of the central star increases by up to an order of magnitude (FU Ori-like events?). We are currently investigating this.
N. Cuello, G. Dipierro, D. Mentiplay et al. – MNRAS (2019)
N. Cuello, F. Louvet, D. Mentiplay et al. – MNRAS (2020)
R. Nealon, N. Cuello & R. Alexander – MNRAS (2020)
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In addition, we are working on the modelling of individual sources where we suspect an ongoing stellar flyby. For instance, AS 205, FU Ori, UX Tau, and Z CMa are binary systems with strong hints of interaction between the stars and the discs. More soon!
Project |03
SHADOWS IN DISCS,
DUST & SPIRALS,
PLANET MIGRATION
Intriguing shadows have been reported in protoplanetary disk observations in the last years. They can be due to the presence of a (precessing) inclined inner disc close to the star. Static shadows can trigger spiral formation in the disk as shown by Montesinos+2016. However, if the shadows move and are prograde, it is possible to form planetary-like spirals. Also, we wish to understand the illumination patterns caused by the material around the (forming) planets in the disc and their observational signatures.
M. Montesinos & N. Cuello - MNRAS Letters (2018)
M. Montesinos, N. Cuello et al. (resubmitted)
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Considering dust on top of these structures, we showed that dust concentrates efficiently inside these shadow-triggered spirals. Although this kind of spirals are hardly detectable with ALMA, they deeply affect dust growth and planetesimal formation in the disc.
N. Cuello, M. Montesinos, S. Stammler et al. – A&A (2019)
As planets grow in the disc, the exchange of angular momentum with the gaseous component of the protoplanetary disc produces a net torque resulting in planet migration. Planet's luminosity due to solid accretion can slow or even reverse planet migration. Here, we study updated type I migration rates for non-isothermal discs and the role of planet's luminosity over such rates. We find that the latter can have important effects on planetary evolution, producing a significant outward migration for low-mass growing planets.
O.M. Guilera, N. Cuello, M. Montesinos et al. – MNRAS (2019)
Project |04
PHOTOPHORESIS,
SOLAR NEBULA &
METEORITES
Photophoresis is a force due to the momentum exchange between gas particles and illuminated dust particles. Its main effect is to move solid particles away from the radiation source. We include this force in a hydrodynamical code in order to understand how it affects the dust in protoplanetary disks. In the optically thin regions, photophoresis leads to the outward motion of solid bodies, from 1mm to 1m approx. This prevents their accretion onto the central star and results in a radial mixing of dust. This can be ultimately connected to the meteoritic composition of our Solar System.
N. Cuello, J.-F. Gonzalez, F.C. Pignatale – MNRAS (2016)
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I also worked on a stellar fountain model in order to explain Calcium-Aluminium rich Inclusions (CAIs) formation in the Solar Nebula. We considered cooling and heating processes during the ejection phase of these solids.
K. Liffman, N. Cuello, D. A. Paterson - MNRAS (2016)
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Finally, we also studied differential vertical sedimentation and radial-drift for different chemical species. This allowed us to understand how ice, organics, silicates, and iron were mixed during the early phases of the Solar Nebula.
F.C. Pignatale, J.-F. Gonzalez, N. Cuello et al. - MNRAS (2017)
Project |05
PLOONETS, EXOMOONS & PLANETARY RING FORMATION
Ploonets: moons that become planets. We explore the scenario where large regular exomoons escape after tidal interchange of angular momentum with its parent planet, becoming small planets by themselves. By performing semi-analytical simulations of tidal interactions between a large moon with a close-in giant, and integrating numerically their orbits for several Myr, we found that in ~50% of the cases a young ploonet may survive ejection from the planetary system, or collision with its parent planet and host star, being in principle detectable. Volatile-rich ploonets are dramatically affected by stellar radiation during both planetocentric and siderocentric orbital evolution, and their radius and mass change significantly due to the sublimation of most of their material during time-scales of hundreds of Myr. We estimate the photometric signatures that ploonets may produce if they transit the star during the phase of evaporation, and compare them with noisy light curves of known objects (Kronian stars and non-periodical dips in dusty light curves). Additionally, the typical transit timing variations (TTV) induced by the interaction of a ploonet with its planet are computed. We find that present and future photometric surveys' capabilities can detect these effects and distinguish them from those produced by other nearby planetary encounters.
Project |06
VISUALISATION OF ASTROPHYSICAL SIMULATIONS IN 360º (4π)
Youtube videos soon.
Just a sample of my work. To see more or discuss possible work >>