The lives of massive stars from birth to supernovae

Lead Research Organisation: Queen's University of Belfast
Department Name: Sch of Mathematics and Physics

Abstract

Supernovae are at 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. Recently I have shown the potential of a new project that could discover the progenitors of 20-30 supernovae over the 5-year period of this grant; this will determine the masses, luminosities and temperatures of massive stars before they die as supernovae. We see a great diversity in supernova types and we believe the reason lies in the type 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 aims at understanding how massive stars live and evolve, how factors such as metallicity, mass-loss and stellar rotation effect 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.

Publications

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Bauer F (2008) Supernova 1996cr: SN 1987A's Wild Cousin? in The Astrophysical Journal

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Botticella M (2009) SN2008S an intriguing event

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Botticella M (2009) SN 2008S: an electron-capture SN from a super-AGB progenitor? in Monthly Notices of the Royal Astronomical Society

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Crockett R (2008) The type IIb SN 2008ax: the nature of the progenitor in Monthly Notices of the Royal Astronomical Society: Letters

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Crockett R (2008) The Birth Place of the Type Ic Supernova 2007gr in The Astrophysical Journal

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Eldridge J (2007) Ruling out a massive asymptotic giant-branch star as the progenitor of supernova 2005cs in Monthly Notices of the Royal Astronomical Society: Letters

 
Description The aim of the proposal was to complete two projects under my leadership. Project I was an ESO VLT Large Programme "The VLT Survey of Massive stars". The second, which I will call Project II below wa "Identifying the progenitors of core-collapse supernovae". During the course of my EURYI grant, I also developed a third project, related to these two - the Pan-STARRS Supernovae survey. This latter was unexpected at the time that the EURYI grant was awarded, but I used some of the funding to secure a leadership role and early science results.

Highlights from my 5-year EURYI award are as follows :
- 57 papers in refereed journals published between 2005-2010
- 3 discovery letters to Science and Nature
- an invitation to write for Annual Reviews in 2009
- Philip Leverhulme Prize 2005
- 7 successful PhD students supervised during this period
- University leverage support that has allowed me to build one of the largest SN research groups in the world
- Elected Chair of Pan-STARRS Science Council
- Selected as PI of ESO Public Spectroscopic survey proposal (only 1 of 2 proposals to be invited to submit a full proposal in 2011)
- Large amount of telescope time awarded to my group (e.g. 134hrs of VLT time since 2006 ; 146hrs on Gemini since 2006)
- 20 invited talks or SOC membership at international conferences (2005-2010)


Project I:
I was Principal Investigator and team leader for the ESO Large Programme "The VLT
FLAMES survey of massive stars". We were awarded Large programme status on the VLT, and as team leader I organized the definition and division of work packages, coordinated six consortium workshops, and managed the survey to successful completion (11 refereed papers). This has been the most extensive survey of massive stars ever undertaken and the European consortium consisted of leaders in the modeling of stellar atmospheres and winds. As well as managing the overall coordination, I jointly supervised Ian Hunter, a PhD student at Queen's and we led
the analysis of several hundred B-type stars. This led to 5 papers with Ian Hunter as lead author, and has had a major impact in the field. We measured the intrinsic rotational velocity distribution of stars in the LMC and SMC for the first time, and a chemical analysis shows that the standard rotating models do not match observation.

Project II:
Over the past five years I have been the field leader in determining which stars explode as core collapse supernovae. I established a method to determine which massive stars produce which types of core-collapse supernovae. With my group, I have directly identified stars before explosion and witnessed their disappearance years after. This project has significantly changed the field. Highlights are an invitation to write for Annual Reviews, five discovery papers in Science and Nature, and four successful PhD student theses in the supernova and progenitor area. In particular this culminated in a paper in MNRAS in 2009 (2nd highest cited MNRAS paper for that year), which analysed all our discoveries in a homogeneous way. This shows that the progenitors of type II-P supernovae are red supergiants, determines the low mass limit for supernovae (8 solar masses) and shows that there may be a missing population of black hole forming supernovae from the most massive stars.

Project III
During my EURYI award (and because of this large award), Queen's University invested £340k on my behalf for us to join the Pan-STARRS Science Consortium. I have become a Key Project leader, chair of the Science Council and manager of the "Transient Science Sever"; development. This is a software infrastructure project to automatically classify transients as they are discovered. My group published the first two science papers to come from Pan-STARRS, and is leading the search for the new class of "ultra-bright" supernovae at high redshift.
Exploitation Route I carried out a very large amount of outreach and PR duties as part of this grant. I have had several press releases, issued through Queen's, STFC, RAS, HST ECF.

An non-exhaustive list of examples is :
http://news.bbc.co.uk/1/hi/northern_ireland/4443788.stm
http://www.stfc.ac.uk/News%20and%20Events/3363.aspx
http://www.gemini.edu/node/11244
http://www.spacetelescope.org/news/heic0808/
http://www.telegraph.co.uk/science/science-news/7836892/Telescope-to-reveal-secrets-of-universe.html
Sectors Education,Other

URL http://star.pst.qub.ac.uk/~sjs
 
Description A very large number of public outreach duties. This grant allowed my profile in the field to be raised to such an extent that I was frequently invited to talk about supernovae in the public and educational domain. Both specifically on my research and generally on supernovae and astronomy. It raised my profile in N. Ireland in particular such that I became a key go-to person for the media to request interviews and opinions on astronomy and space stories. • Cambridge University Astronomy Society, November 2011 • The Naked Scientists, podcast (25th Nov 2011 "Stars and supernovae") • BBC Radio Ulster interview on Space Shuttle retirement 8th July 2011 • BBC Radio Ulster "What's next" contributor June 2011 • BBC Radio Ulster interview on Gagarin 50th Anniversary of human spaceflight 13th April 2011 • BBC Radio interviews on astronomy at Queen's : 31st March 2011 • Coordinator for Queen's University support for Irish Astronomical Association public lectures and events. Member of IAA Council (2007 - present) • Organiser of public lecture evening "The Great Cosmic Puzzle", speakers Prof. Carlos Frenk (Durham), Prof. Chris Stubbs (Harvard), at Queen's University Belfast, Sept. 2010 • Lecture at astronomy weekend : COSMOS 2010, Tullamore, Co. Offaly, July 2010 • Science Podcasts and journalism with sixth form students, in collaboration with Queen's School of Education (2009) • Public lecture - Trinity Science Week, Trinity College Dublin, May 2009 • BBC Radio interview on "Exploding stars and blackholes", 30th July 2008 • Public talk - Irish Astronomical Association, Belfast, 2008 • Ulster Television - evening talk show guest on the National Astronomy week public lecture series, April 2008 • Public lecture for Astronomy Ireland, Trinity College, Dublin, September 2007 • Lecture for Secondary School World Space week , October 2007 • Sky at Night Magazine Article "Masterclass on supernovae", March 2006 • Public talk - Irish Astronomical Association, Belfast, January 2006 • School teacher's lecture "Sizing up our galaxy - stars and space travel", Queen's, June 2007 • BBC News 24 - interview on the most luminous supernovae (2006) • School's lecture for Horizons in Physics "The dark side of the Universe", June 2006 • Public talk - East Antrim Astronomical Society, Ballyclare, 2005
First Year Of Impact 2006
Sector Education,Culture, Heritage, Museums and Collections,Other
Impact Types Cultural,Societal

 
Description See the list in the narrative 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Schools
Results and Impact Significant increase in interest in astronomy and science in general from the talks, PRs etc.

Increase in number of work experience requests for physics based opportunities. Quantitative increase in applications to Physics course from students in NI - I don't personally take credit for this, but all my outreach activities contributed to the University's Physics amd astronomy extensive outreach programme which did lead to increase in applications and students studying Physics based courses (quantifiable evidence submitted to REF 2013).
Year(s) Of Engagement Activity 2006,2007,2008,2009,2010
URL https://star.pst.qub.ac.uk/wiki/doku.php/public/outreach/outreach_history_2008_may2014