NEWS & PRESS
Surprisingly low temperatures detected in the remnant of the supernova 1987A may explain the mystery of why space is so abundant with dust grains and molecules. The results will be presented by Dr Mikako Matsuura at the National Astronomy Meeting 2013 in St Andrews on Friday 5 July.
In 1987, an explosion of a massive star was detected in our neighbouring galaxy, the Large Magellanic Cloud, just 170,000 light years away. This supernova, dubbed 1987A, released approximately thousand million times more energy than that emitted by the Sun in one year. Twenty five years later, an international team of astronomers has used the Herschel Space Observatory and Atacama Millimeter and Submillimeter Array (ALMA) to study the supernova remnant. They found a vast reservoir of unexpectedly cold molecules and dust.
"The powerful explosion we saw in 1987 scattered elements made by star into space in the form of a very hot plasma. The gas has now cooled down to temperatures between -250 to -170 degrees Celsius. That’s surprisingly cold, comparable to the icy surface of Pluto at the edge of our Solar System. The gas has formed molecules and some has even condensed into solid grains of dust. The supernova has now become a super freezer!" said Dr Matsuura.
The Herschel observations show that the supernova produced dust and solid material equal to about 250 000 times the mass of the Earth, or three quarters of the mass of the Sun. To date, scientists have believed that supernova remnants contain only very energetic atomic gas, detectable at optical X-ray wavelengths; the new observations show that this is not the case. The discovery of such a large mass of dust should help us to understand how supernovae slowly spread and fill galaxies with gas, dust and small rocky particles, some of which may eventually end up in the next generation of stars and planets.
"We were surprised by the amount of dust and molecular gas in the reservoir created by the supernova 1987A. The ALMA and Herschel observations show that the reservoir contains carbon monoxide molecules equalling one tenth of the mass of the Sun. Herschel shows that the dust mass was even larger - about half the solar mass!" said Dr Matsuura.
"We don't get many opportunities to study supernova. These events are very rare and the majority was found in very distant galaxies. Even with relatively close ones, like 1987A, it’s difficult – although they are very bright at the time of the explosion, the light from the supernovae fades very quickly making it very difficult to observe them a few years after the explosion," said Dr Matsuura. "Carl Sagan once said that: ‘We are all made of star-stuff’. These results will help us understand how that material reached us!"
The international team includes: Mikako Matsuura and M.J. Barlow of University College London, Maarten Baes of Universiteit Gent, Eli Dwek of NASA Goddard, Margaret Meixner of the Space Telescope Science Institute, J. Kamenetzky and R. McCray of the University of Colorado at Boulder and R. Indebetouw of the University of Virginia.
ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Figure 1 Hubble Space Telescope image of supernova 1987A (Credit: ESA, NASA, P. Challis and R. Kirshner) The keyhole-like shape at the centre is the remnant of the supernova explosion 1987A. This remnant is still expanding with a speed of 2200 km per second. It is believed that the surrounding ring was formed before the explosion. http://hubblesite.org/newscenter/archive/releases/2007/10/image/a/
Figure 2 (Credit: Kamenetzky et al, Astrophysical Journal Letters (submitted)) The ALMA composite image of supernova 1987A, overlaid on the optical and near-infrared images. The ALMA image, indicated in red, captured the molecular reservoir in the remaining of supernova 1987A. http://www.ras.org.uk/images/stories/NAM2013/5July/matsuura2.jpg
Dr Mikako Matsuura
University College London
Dr Robert Massey
Royal Astronomical Society
Tel: +44 (0)20 7734 3307 / 4582 x214
Mob: +44 (0)794 124 8035
Ms Anita Heward
Royal Astronomical Society
Mob: +44 (0)7756 034 243
Ms Emma Shea
Head of Development Communications
University of St Andrews
Tel: +44 (0)1334 462 167
Mob: +44 (0)785 090 0352
Landline numbers in NAM 2013 press room (available from 9 a.m. to 5 p.m. from 1-4 July, 9 a.m. to 3 p.m. 5 July): Tel: +44 (0)1334 462231, +44 (0)1334 46 2232
NOTES FOR EDITORS
Bringing together more than 600 astronomers and space scientists, the RAS National Astronomy Meeting (NAM 2013) will take place from 1-5 July 2013 at the University of St Andrews, Scotland. The conference is held in conjunction with the UK Solar Physics (UKSP: www.uksolphys.org) and Magnetosphere Ionosphere Solar Terrestrial (MIST: www.mist.ac.uk) meetings. NAM 2013 is principally sponsored by the RAS, STFC and the University of St Andrews and will form part of the ongoing programme to celebrate the University’s 600th anniversary.
Meeting arrangements and a full and up to date schedule of the scientific programme can be found on the official website at http://www.nam2013.co.uk The Royal Astronomical Society (RAS: www.ras.org.uk, Twitter: @royalastrosoc), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organises scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 3500 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.
The Science and Technology Facilities Council (STFC: www.stfc.ac.uk, Twitter: @stfc_matters) is keeping the UK at the forefront of international science and tackling some of the most significant challenges facing society such as meeting our future energy needs, monitoring and understanding climate change, and global security. The Council has a broad science portfolio and works with the academic and industrial communities to share its expertise in materials science, space and ground-based astronomy technologies, laser science, microelectronics, wafer scale manufacturing, particle and nuclear physics, alternative energy production, radio communications and radar. It enables UK researchers to access leading international science facilities for example in the area of astronomy, the European Southern Observatory.
Founded in the 15th century, St Andrews is Scotland’s first university and the third oldest in the English speaking world. Teaching began in the community of St Andrews in 1410 and the University was formally constituted by the issue of Papal Bull in 1413. The University is now one of Europe’s most research intensive seats of learning – over a quarter of its turnover comes from research grants and contracts. It is one of the top rated universities in Europe for research, teaching quality and student satisfaction and is consistently ranked among the UK’s top five in leading independent league tables produced by The Times, The Guardian and the Sunday Times. The University is currently celebrating its 600th anniversary and pursuing a £100 million fundraising campaign, launched by Patron and alumnus HRH Prince William Duke of Cambridge, including £4 million to fund the creation of an ‘Other Worlds’ Think Tank and Observatory. The new think tank and Observatory project will extend the University of St Andrews’ flagship work on extra-solar planets, and provide a creative environment for problem-focused research, education and continuing public engagement. For further information go to: www.st-andrews.ac.uk/600/