Forever young: unravelling the mystery of “Peter Pan” stars

Description

“Peter Pan” stars are a rare and intriguing class of low-mass stars that appear not to grow up. Despite ages of ~20-50 Myr, these objects still show clear signatures of youth, including active accretion, strong magnetic activity, and long-lived circumstellar discs - features that most planet formation theories predict should disappear within the first few million years. This PhD project builds directly on the research interests of Dr Simon Murphy who has played a leading role in identifying and characterising young nearby stellar populations.

You will assemble and analyse a sample of candidate Peter Pan stars in the solar neighbourhood using data from Gaia, SkyMapper, and infrared surveys such as WISE and Spitzer, combined with available spectroscopy. The project will focus on confirming ages, membership in young associations, and the presence of discs and accretion using diagnostics such as lithium absorption, Hα emission, rotation rates, and infrared excesses.

A central aim is to determine why these stars evolve so slowly. Are their extended disc lifetimes driven by low stellar mass, binarity, magnetic field strength, or environmental factors? By comparing Peter Pan stars to “normal” young stars of similar mass and age, the project will test competing models of disc dispersal and angular momentum evolution. The work will also explore the implications for planet formation, as long-lived discs may allow planets to form over much longer timescales than previously thought.

This project offers an HDR student hands-on experience with large survey datasets, stellar youth diagnostics, and statistical population studies, while addressing a high-impact and rapidly developing problem in modern astrophysics.