Stephen Smartt

The Project

Understanding the lives of massive stars from birth to supernovae.


Stephen Smartt
Queen's University Belfast
Department of Physics and Astronomy
Belfast, Northern Ireland



Stephen Smartt, 37 years old, is a PPARC Advanced Fellow and Lecturer at Queen's University of Belfast, Northern Ireland. He obtained his Ph.D in Astrophysics from Queen's in 1996, and then spent three years working as an astronomer at the Isaac Newton Group of Telescopes on La Palma, in the Canary Islands. He took up a two-year postdoctoral position in the UK's Hubble Space Telescope Support Facility at the University of Cambridge in 1999. In 2001 he was awarded a PPARC Advanced fellowship at Cambridge, and moved to Queen's in 2004.



Project Description

Supernovae(*) are the heart of our attempts to understand some of the most important problems of modern astronomy. They have created the heavy chemical elements we now see in the Universe and their large kinetic energies mean they have been key components in the formation of galaxies.

Thermonuclear supernovae have been used to measure the acceleration of the distant Universe providing evidence for the mysterious dark energy that pervades space. Gamma Ray Bursts probably arise when a very massive star dies in a highly energetic supernova producing a black hole and relativistic jet. The nature of the progenitor stars of supernovae is fundamental to our understanding of these enigmatic phenomena. However we know very little about the progenitor systems of supernovae and have successfully identified the progenitors of only two nearby explosions. These two supernovae were very peculiar and their progenitors did not match the standard ideas of stellar evolution.

The aim of this project is to discover the progenitors of about 30 supernovae in the next five years and to measure the masses, luminosities and temperatures of stars before they die as supernovae. We see a great diversity in supernova types and we believe the reason lies in the type of and size of star that explodes; however we do not yet have the observational evidence to prove this or enough knowledge to model it confidently.

This project also aims at understanding how massive stars live and evolve, how factors such as metallicity, mass-loss and stellar rotation affect their evolution and ultimately what type of supernovae they produce. As massive stars and supernovae have had a crucial role in shaping our Universe it is imperative we understand their origins.

(*) Definition - supernovae:
Supernovae refer to several types of stellar explosions that produce extremely bright objects made of plasma that decline to invisibility over weeks or months. Supernova explosions are the main source of all the elements heavier than oxygen, and they are the only source of many important elements. For example, all the calcium in our bones and all the iron in our hemoglobin were synthesized in a supernova explosion, billions of years ago. Supernovae inject these heavy elements into the interstellar medium, thus enriching the molecular clouds that are the sites of stellar formation. This enrichment process is what determined the composition of the Solar System 4.5 billion years ago, and ultimately made possible the chemistry of life on Earth as we know it as per the "Big Bang" theory. Supernovae generate tremendous temperatures, and under the right conditions, the fusion reactions that take place during the peak moments of a supernova can produce some of the heaviest elements like californium. (Source: Wikipedia)