The origin of the iron-rich knot in tycho's supernova remnant
- NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States)
- Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States)
- Department of Physics and Astronomy and Pittsburgh Particle Physics, Astrophysics and Cosmology Center (PITT PACC), University of Pittsburgh, 3941 O’Hara Street, Pittsburgh, PA 15260 (United States)
- E.T.S. Arquitectura del Vallès, Universitat Politècnica de Catalunya, Carrer Pere Serra 1-15, E-08173 Sant Cugat del Vallès (Spain)
- Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT, 2611 (Australia)
- Department of Physics, University of Texas at Arlington, Box 19059, Arlington, TX 76019 (United States)
X-ray observations of supernova remnants (SNRs) allow us to investigate the chemical inhomogeneity of ejecta, offering unique insight into the nucleosynthesis in supernova explosions. Here we present detailed imaging and spectroscopic studies of the “Fe knot” located along the eastern rim of the Type Ia SNR Tycho (SN 1572) using Suzaku and Chandra long-exposure data. Surprisingly, the Suzaku spectrum of this knot shows no emission from Cr, Mn, or Ni, which is unusual for the Fe-rich regions in this SNR. Within the framework of the canonical delayed-detonation models for SN Ia, the observed mass ratios M{sub Cr}/M{sub Fe}<0.023, M{sub Mn}/M{sub Fe}<0.012, and M{sub Ni}/M{sub Fe}<0.029 (at 90% confidence) can only be achieved for a peak temperature of (5.3–5.7) × 10{sup 9} K and a neutron excess of ≲2.0×10{sup −3}. These constraints rule out the deep, dense core of a Chandrasekhar-mass white dwarf as the origin of the Fe knot and favor either incomplete Si burning or an α-rich freeze-out regime, probably close to the boundary. An explosive He burning regime is a possible alternative, although this hypothesis is in conflict with the main properties of this SNR.
- OSTI ID:
- 22869546
- Journal Information:
- Astrophysical Journal, Vol. 834, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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