It is assumed that the radioactive decay of (44)Ti powers the infrared, optical and ultraviolet emission of supernova remnants after the complete decay of (56)Co and (57)Co (the isotopes that dominated the energy balance during the first three to four years after the explosion) until the beginning of active interaction of the ejecta with the surrounding matter. Simulations show that the initial mass of (44)Ti synthesized in core-collapse supernovae is (0.02-2.5) × 10(-4) solar masses (M circled dot). Hard X-rays and γ-rays from the decay of this (44)Ti have been unambiguously observed from Cassiopeia A only, leading to the suggestion that values of the initial mass of (44)Ti near the upper bound of the predictions occur only in exceptional cases. For the remnant of supernova 1987A, an upper limit to the initial mass of (44)Ti of <10(-3) M circled dot has been obtained from direct X-ray observations, and an estimate of (1-2) × 10(-4) M circled dot has been made from infrared light curves and ultraviolet spectra by complex and model-dependent computations. Here we report observations of hard X-rays from the remnant of supernova 1987A in the narrow band containing two direct-escape lines of (44)Ti at 67.9 and 78.4 keV. The measured line fluxes imply that this decay provided sufficient energy to power the remnant at late times. We estimate that the initial mass of (44)Ti was (3.1 ± 0.8) × 10(-4), which is near the upper bound of theoretical predictions.
X-ray Illumination of the Ejecta of Supernova 1987AJ Larsson et al. Nature 474 (7352), 484-6. PMID 21654749.When a massive star explodes as a supernova, substantial amounts of radioactive elements--primarily (56)Ni, (57)Ni and (44)Ti--are produced. After the initial flash of li …
Supernovae. ⁴⁴Ti Gamma-Ray Emission Lines From SN1987A Reveal an Asymmetric ExplosionSE Boggs et al. Science 348 (6235), 670-1. PMID 25954004.In core-collapse supernovae, titanium-44 ((44)Ti) is produced in the innermost ejecta, in the layer of material directly on top of the newly formed compact object. As suc …
Asymmetries in Core-Collapse Supernovae From Maps of Radioactive 44Ti in Cassiopeia ABW Grefenstette et al. Nature 506 (7488), 339-42. PMID 24553239.Asymmetry is required by most numerical simulations of stellar core-collapse explosions, but the form it takes differs significantly among models. The spatial distributio …
Cobalt-56 γ-Ray Emission Lines From the Type Ia Supernova 2014JE Churazov et al. Nature 512 (7515), 406-8. PMID 25164750.A type Ia supernova is thought to be a thermonuclear explosion of either a single carbon-oxygen white dwarf or a pair of merging white dwarfs. The explosion fuses a large …
Supernovae. The Bubble-Like Interior of the Core-Collapse Supernova Remnant Cassiopeia AD Milisavljevic et al. Science 347 (6221), 526-30. PMID 25635094.The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of these catastrophic explosions remain unc …
- Nature. 2011 Jun 08;474(7352):484-6 - PubMed