X-Ray Studies of the Inverted Ejecta Layers in the Southeast Area of Cassiopeia A

Abstract The central strong activities in core-collapse supernovae are expected to produce the overturning of the Fe- and Si/O-rich ejecta during the supernova explosion based on multidimensional simulations. X-ray observations of the supernova remnant Cassiopeia A have indicated that the Fe-rich ej...

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Published inThe Astrophysical journal Vol. 932; no. 2; pp. 93 - 100
Main Authors Tsuchioka, Tomoya, Sato, Toshiki, Yamada, Shinya, Uchiyama, Yasunobu
Format Journal Article
LanguageEnglish
Published Philadelphia The American Astronomical Society 01.06.2022
IOP Publishing
Subjects
Astrophysics
Cassiopeia A
Ejecta
Explosions
Interstellar medium
Iron
Mass ratios
Nucleosynthesis
Proper motions
Space telescopes
Stellar evolution
Supernova
Supernova remnants
Supernovae
X ray telescopes
X-ray astronomy
X-rays
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Summary:Abstract The central strong activities in core-collapse supernovae are expected to produce the overturning of the Fe- and Si/O-rich ejecta during the supernova explosion based on multidimensional simulations. X-ray observations of the supernova remnant Cassiopeia A have indicated that the Fe-rich ejecta lies outside the Si-rich materials in the southeastern region, which is consistent with the hypothesis on the inversion of the ejecta. We investigate the kinematic and nucleosynthetic properties of the inverted ejecta layers in detail to understand its formation process using the data taken by the Chandra X-Ray Observatory. Three-dimensional velocities of Fe- and Si/O-rich ejecta are obtained as >4500 km s −1 and ∼2000–3000 km s −1 , respectively, by combining proper motion and line-of-sight velocities, indicating that the velocity of the Si/O-rich ejecta is slower than that of the Fe-rich ejecta from the early stages of the explosion. To constrain their burning regime, the Cr/Fe mass ratios are evaluated as 0.51 − 0.10 + 0.11 % in the outermost Fe-rich region and 1.24 − 0.20 + 0.19 % in the inner Fe/Si-rich region, suggesting that the complete Si burning layer is invertedly located to the incomplete Si burning layer. All the results support the ejecta overturning at the early stages of the remnant’s evolution or during the supernova explosion of Cassiopeia A.
Bibliography:AAS37730
High-Energy Phenomena and Fundamental Physics
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/ac6e63