Public Release: 

Double explosion heralds the death of a very massive star

Science and Technology Facilities Council

A unique discovery of two celestial explosions at exactly the same position in the sky has led astronomers to suggest they have witnessed the death of one of the most massive stars that can exist. A global collaboration of astronomers, led by Queen's University Belfast teamed up with Japanese supernova hunter Koichi Itagaki to report an amazing new discovery in Nature this week (June 14th). This is the first time such a double explosion has been observed and challenges our understanding of star-deaths.

In 2004 Koichi Itagaki discovered an exploding star in the galaxy UGC4904 (78 million light years away in the Lynx constellation), which rapidly faded from view in the space of 10 days. It was never formally announced to the community, but then he then found a new much brighter explosion in the same place only two years later in 2006, which he proposed as new supernova. Queen's astronomers Prof. Stephen Smartt and Dr. Andrea Pastorello immediately realised the implications of finding two explosions at the same position on the sky.

They began observing the 2006 supernova (named SN2006jc) with a wide range of large telescopes and analysed Itagaki's images to show that the two explosions were exactly in the same place. The most likely explanation for the 2004 explosion was probably an outburst of a very massive star like Eta-Carinae, which was observed to have a similar giant outburst in the 1850s. The 2006 supernova was the final death of the same star.

Dr. Pastorello said "We knew the 2004 explosion could be a giant outburst of very massive star, and we know that only the most massive stars can produce this type of outburst. So the 2006 supernova must have been the death of the same star, possibly a star 50 to 100 times more massive than the Sun. And it turns out that SN2006jc is a very weird supernova - unusually rich in the chemical element helium which supports our idea of a massive star outburst then death."

Dr. Pastorello used UK telescopes on La Palma (the Liverpool Telescope, and William Herschel Telescope) in a combined European and Asian effort to monitor the energetics of SN2006jc. He showed that the exploding star must have been a Wolf-Rayet star, which are the carbon-oxygen remains of originally very high mass stars.

Prof Smartt is funded by a prestigious EURYI fellowship to study the birth and death of stars. He said "The supernova was the explosion of a massive star that had lost its outer atmosphere, probably in a serious of minor explosions like the one Koichi found in 2004. The star was so massive it probably formed a black hole as it collapsed. This is the first time two explosions of the same star have been found, and it challenges our theories of the way stars live and die. "

Although this is the first time two such explosions have been found to be coincident, they could be more frequent than currently thought. The future Pan-STARRS project, a new telescope with the world's largest digital camera which can survey the whole sky once a week could search for these peculiar supernovae. Queen's are partners in the Pan-STARRS science team and hope to use it to understand how the most massive stars in the Universe die.


The Science and Technology Facilities Council funds UK research in astronomy and access to telescopes such as the William Herschel Telescope.

Notes for Editors

Suggested Graphics:

Caption: This is an image of Eta-Carina in our galaxy, taken with the Hubble Space Telescope. The star that exploded in 2004 and 2006 in the far off galaxy 2006 was likely a very massive star like Eta-Carina, of up to 100 solar masses, and doomed to death when its core collapsed to a black hole. Credit: NASA/ESA Hubble Space Telescope and Jon Morse

The Great Carina Nebula (NGC 3372), famous star-forming region of the southern sky. The image spans about 40 light-years within the larger Carina Nebula at an estimated distance of 7,500 light-years. The Carina Nebula is home to young, extremely massive stars, including Eta Carinae, a star with well over 100 times the mass of the Sun. Highlighted by diffraction spikes, Eta is just above and right (east) of the Keyhole. Credit: Brad Moore

Animation and Artist's impressions

Credit (c) Frederic Durillon -, Courtesy Service d'Astrophysique/CEA


Prof. Stephen Smartt
Astrophysics Research Centre, School of Maths and Physics
Queen's University Belfast
Work: 02890 971245 Home: 02890 962471 Mobile:07876014103

Dr. Andrea Pastorello
Astrophysics Research Centre, School of Maths and Physics
Queen's University Belfast
Work: 02890 97 3509 Mobile: 07990964240

Partner Press Releases (links live after embargo expires):

Paper details
Title: A giant outburst two years before the core-collapse of a massive star
Authors: A. Pastorell, S. J. Smartt, S. Mattila, J. J. Eldridge, D. Young, K. Itagaki, H. Yamaoka, H. Navasardyan, S. Valenti, F. Patat, I. Agnoletto, T. Augusteijn, S. Benetti, E. Cappellaro, T. Boles, J.-M. Bonnet-Bidaud, M.T. Botticella, F. Bufano, C. Cao, J. Deng, M. Dennefeld, N. Elias-Rosa, A. Harutyunyan, F. P. Keenan, T. Iijima, V. Lorenzi, P. A. Mazzali, X. Meng, S. Nakano, T.B. Nielsen, J. V. Smoker, V. Stanishev, M. Turatto, D. Xu, L. Zampierio


About the Liverpool Telescope

The Liverpool Telescope, with a two metre mirror, is a fully robotic astronomical telescope owned and operated by the Astrophysics Research Institute of Liverpool John Moores University in north-west England. It is the most advanced telescope of its kind in the world, operating completely autonomously, independent of human control. The telescope is a specialist instrument for the study of time-variable astronomical phenomena.

The telescope was designed and built by Telescope Technologies Limited, a spin-off company of the University.

About the William Herschel Telescope

The William Herschel Telescope is one of the telescopes of the Isaac Newton Group (ING). The ING is owned and operated jointly by the Science and Technology Facilities Council of the United Kingdom, the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) of the Netherlands and the Instituto de Astrofísica de Canarias (IAC) of Spain. The telescopes are located in the Spanish Observatorio del Roque de Los Muchachos on La Palma, Canary Islands which is operated by the Instituto de Astrofísica de Canarias (IAC)

Science and Technology Facilities Council

The Science and Technology Facilities Council ensures the UK retains its leading place on the world stage by delivering world-class science; accessing and hosting international facilities; developing innovative technologies; and increasing the socio-economic impact of its research through effective knowledge-exchange partnerships.

The Council has a broad science portfolio including Astronomy, Particle Physics, Particle Astrophysics, Nuclear Physics, Space Science, Synchrotron Radiation, Neutron Sources and High Power Lasers. In addition the Council will manage and operate three internationally renowned laboratories:

  • The Rutherford Appleton Laboratory, Oxfordshire
  • The Daresbury Laboratory, Cheshire
  • The UK Astronomy Technology Centre, Edinburgh

The Council gives researchers access to world-class facilities and funds the UK membership of international bodies such as the European Laboratory for Particle Physics (CERN), the Institute Laue Langevin (ILL), European Synchrotron Radiation Facility (ESRF), the European organisation for Astronomical Research in the Southern Hemisphere (ESO) and the European Space Agency (ESA). It also contributes money for the UK telescopes overseas on La Palma, Hawaii, Australia and in Chile, and the MERLIN/VLBI National Facility, which includes the Lovell Telescope at Jodrell Bank Observatory.

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