The high ratio of44Ti/56Ni in Cassiopeia a and the axisymmetric collapse-driven supernova explosion

Shigehiro Nagataki, Masa-Aki Hashimoto, Katsuhiko Sato, Shoichi Yamada, Yuko S. Mochizuki

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Abstract

The large abundance ratio of 44Ti/56Ni in Cassiopeia A is puzzling. In fact, the ratio seems to be larger than the theoretical constraint derived by Woosley & Hoffman. However, this constraint is obtained on the assumption that the explosion is spherically symmetric, whereas Cas A is famous for the asymmetric form of the remnant. Recently, Nagataki et al. calculated the explosive nucleosynthesis of axisymmetrically deformed collapse-driven supernova. They reported that the ratio of 44Ti/56Ni was enhanced by the stronger alpha-rich freezeout in the polar region. In this Letter, we apply these results to Cas A and examine whether this effect can explain the large amount of 41Ti and the large ratio of 44Ti/56Ni. We demonstrate that the conventional, spherically symmetric explosion model cannot explain the 44Ti mass produced in Cas A if its lifetime is shorter than ∼80 yr and the intervening space is transparent to the gamma-ray line from the decay of 44Ti. On the other hand, we show that the axisymmetric explosion models can solve the problem. We expect the same effect from a three-dimensionally asymmetric explosion, since the stronger alpha-rich freezeout will also occur in that case in the region where the larger energy is deposited.

Original languageEnglish
JournalAstrophysical Journal
Volume492
Issue number1 PART II
Publication statusPublished - Jan 1 1998

Fingerprint

supernovae
explosions
explosion
Cassiopeia A
polar region
nuclear fusion
polar regions
explosive
gamma rays
life (durability)
decay
energy
effect

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Nagataki, S., Hashimoto, M-A., Sato, K., Yamada, S., & Mochizuki, Y. S. (1998). The high ratio of44Ti/56Ni in Cassiopeia a and the axisymmetric collapse-driven supernova explosion. Astrophysical Journal, 492(1 PART II).

The high ratio of44Ti/56Ni in Cassiopeia a and the axisymmetric collapse-driven supernova explosion. / Nagataki, Shigehiro; Hashimoto, Masa-Aki; Sato, Katsuhiko; Yamada, Shoichi; Mochizuki, Yuko S.

In: Astrophysical Journal, Vol. 492, No. 1 PART II, 01.01.1998.

Research output: Contribution to journalArticle

Nagataki, S, Hashimoto, M-A, Sato, K, Yamada, S & Mochizuki, YS 1998, 'The high ratio of44Ti/56Ni in Cassiopeia a and the axisymmetric collapse-driven supernova explosion', Astrophysical Journal, vol. 492, no. 1 PART II.
Nagataki S, Hashimoto M-A, Sato K, Yamada S, Mochizuki YS. The high ratio of44Ti/56Ni in Cassiopeia a and the axisymmetric collapse-driven supernova explosion. Astrophysical Journal. 1998 Jan 1;492(1 PART II).
Nagataki, Shigehiro ; Hashimoto, Masa-Aki ; Sato, Katsuhiko ; Yamada, Shoichi ; Mochizuki, Yuko S. / The high ratio of44Ti/56Ni in Cassiopeia a and the axisymmetric collapse-driven supernova explosion. In: Astrophysical Journal. 1998 ; Vol. 492, No. 1 PART II.
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