This page is still under construction! Some sections will be filled in when I get the chance.
Second Generation planet-forming discs
Planets form in discs of dust and gas that orbit young stars, which disperse during the first few million years of the star’s life. However, some stars will get a second chance to form planets. Some stars are able to form a new disc at the end of their life, potentially triggering planet formation again. However, another group of stars might be able to form a second disc while they are still young.
By using a simple model of how stars interact with the vast clouds of gas that they form from, we showed that a small but significant fraction of stars might form, disperse their initial discs, and then subsequently pass through a gas cloud that has yet to collapse and form stars itself. As it passes through such a cloud, it can accrete enough gas to form a new disc with similar mass and size to the first disc. This could potentially give the star a second chance to form planets.
Discs in binary systems
We think that half of stars exist in systems with one – or more – companion stars. If planets form as often in these binary systems as they do around solitary stars like our Sun, then half of all planets in the universe may have multiple suns. If we want to understand the process of planet formation, it is therefore important to understand how their formation may be different in binary systems, and how the discs they form from evolve.
A small number of young binaries consist of one star that is bright in the optical, and a second star that is only visible at infrared wavelengths. We believe this happens because the infrared companion is obscured by dust, which may either be the outskirts of the disc of the optically-visible star, or the disc surrounding the infrared companion itself. VV Corona Australis is one such system, and using detailed radiative-transfer modelling we inferred that both stars host discs which are moderately inclined, but that the disc in the infrared companion is more inclined than the optical star’s. This small difference in inclination is sufficient to absorb all the optical light of the star, but leave it visible in the infrared.
Tabby’s star
Coming soon.
VAriable accretion and outbursts
Coming soon.
Peter Scicluna 