Researchers using the ESA Integral space telescope have detected the first evidence of Titanium decay in a supernova about 166,000 light years from Earth in the Large Magellanic Clouds.
The supernova remnant 1987A has provided astronomers with an ongoing science experiment of charting the stages of a star after it has gone Supernova. Initial readings registered fairly low-mass elements like Calcium and Oxygen (atomic weights 14 and 16) in the initial ejecta from the explosion back in 1987 while more recent readings have discovered evidence of higher mass element decay – in this case the decay of 44Ti. The decay of 44Ti has been powering only the innermost part of the remant, the glowing ring pictured above is probably being illuminated by the supernova and its shockwave.
As high-mass stars reach the end of their life, heavier elements are formed as the star collapses in towards itself. These heavy elements are then distributed around the star when it explodes as a Supernova. These elements are not always stable and decay into stable elements, giving off radiation as they do so. This radiation frequently provides the energy source for illuminating clouds of gas as it excites the particles within it, giving off light that we can detect on Earth.
The new study has confirmed that it is the decay of radioactive, unstable 44Ti that has been powering the innermost part of the 1987A remannt. From their analysis of the data, the astronomers estimated that the total mass of titanium-44 that must have been produced just after the core collapse of SN1987A’s progenitor star amounted to 0.03% of the mass of our own Sun. This value is near the upper boundary of theoretical predictions and is nearly twice the amount seen in supernova remnant Cas A, the only other remnant where titanium-44 has been detected.
Phys.org has this quote from the author of the study, Segei Grebenev from the Space Research Institute of the Russian Academy of Science in Moscow:
[box_dark]”This is the first firm evidence of titanium-44 production in supernova 1987A and in an amount sufficient to have powered the remnant over the last 20 years. The high values of titanium-44 measured in Cas A and SNR1987A are likely produced in exceptional cases, favouring supernovae with an asymmetric geometry, and perhaps at the expense of the synthesis of heavier elements.”
“This is a unique scientific result obtained by Integral that represents a new constraint to be taken into account in future simulations for supernova explosions,” adds Chris Winkler, ESA’s Integral project scientist and co-author of the Nature paper.[/box_dark]
Previous studies have shown that the energy from X-rays produced by 44
The paper that is the subject of this article is “Hard-X-ray emission lines from the decay of 44Ti in the remnant of supernova 1987A” – S. A. Grebenev, A. A. Lutovinov,S. S. Tsyganko & C. Winkler; is published in the journal Nature. The abstract is available here.
[toggle_box title=”If you are interested, there are these papers from a quick Arxiv.org trawl for 44Ti emission in supernovae (some about SN1987A, some not) for advanced readers.” width=”Width of toggle box”]
1) (Paper referenced in the text above concerning varying X-ray energy produced by 44Ti in SN1987A) “X-ray illumination of the ejecta of Supernova 1987A” – J. Larsson,C. Fransson, G. Ostlin, P. Gr¨oningsson, A. Jerkstrand, C. Kozma, J. Sollerman, P. Challis, R. P. Kirshner, R. A. Chevalier, K. Heng, R. McCray, N. B. Suntzeff, P. Bouchet, A. Crotts, J. Danziger, E. Dwek, K. France, P. M. Garnavich, S. S. Lawrence, B. Leibundgut, P. Lundqvist, N. Panagia, C. S. J. Pun, N. Smith, G. Sonneborn, L. Wang, J. C. Wheeler.
2) (Another paper where S.A. Grebenev is an author) “Luminosity function of high-mass x-ray binaries and anisotropy in the distribution of active galactic nuclei toward the large magellanic cloud.” – A.A.Lutovinov, S.A.Grebenev and S.S.Tsygankov
3) “Primary gamma-ray spectra in 44Ti of astrophysical interest” – A. C. Larsen, S. Goriely, A. Burger, M. Guttormsen, A. Gorgen, S. Harissopulos, M. Kmiecik, T. Konstantinopoulos, A. Lagoyannis, T. Lonnroth, K. Mazurek, M. Norrby, H. T. Nyhus,G. Perdikakis, A. Schiller, S. Siem, A. Spyrou, N. U. H. Syed, H. K. Toft, G. M. Tveten, and A. Voinov.
4) “The Production of 44Ti and 60Co in Supernova” – F. X. Timmes, S. E. Woosley, D. H. Hartmann & R. D. Homan.
5) “The 44Ti-powered spectrum of SN 1987A” – Anders Jerkstrand, Claes Fransson, Cecilia Kozma.[/toggle_box]