Here we extend the conservation of energy in the framework of the thin layer approximation to the asymmetrical case. Four types of interstellar mediums are analysed, in which the density follows an inverse square prof...Here we extend the conservation of energy in the framework of the thin layer approximation to the asymmetrical case. Four types of interstellar mediums are analysed, in which the density follows an inverse square profile, a power law profile, an exponential profile and a toroidal profile. An analytical solution for the radius as a function of time and the polar angle in spherical coordinates is derived in the case of the inverse square profile. The analytical and numerical results are applied to two supernova remnants: SN 1987A and SN 1006. The back reaction due to the radiative losses is evaluated in the case of the inverse square profile for the surrounding medium. Two models for the image formation are presented, which explain the triple ring visible in SN 1987A and the jet feature of SN 1006.展开更多
I use recent observational and theoretical studies of type Ia supernovae(SNe Ia) to further constrain the viable SN Ia scenarios and to argue that there must be a substantial time delay between the end of the merger o...I use recent observational and theoretical studies of type Ia supernovae(SNe Ia) to further constrain the viable SN Ia scenarios and to argue that there must be a substantial time delay between the end of the merger of the white dwarf(WD) with a companion or the end of mass accretion on to the WD and its terminal explosion. This merger/accretion to explosion delay(MED) is required to allow the binary system to lead to a more or less spherical explosion and to prevent a pre-explosion ionizing radiation. Considering these recent results and the required MED, I conclude that the core degenerate scenario is somewhat more favorable over the other scenarios, followed by the double degenerate scenario. Although the single degenerate scenario is viable as well, it is less likely to account for common(normal) SN Ia. As all scenarios require substantial MED, the MED has turned from a disadvantage of the core degenerate scenario to a challenge that theory should overcome. I hope that the requirement for a MED will stimulate the discussion of the different SN Ia scenarios and the comparison of the scenarios to each other.展开更多
We presume the re-brightening of SN 1006 in AD 1016 as recorded in the ancient Chinese literature to be true and the re-brightening was caused by the encounter either of photons or the shock wave from the SN outburst ...We presume the re-brightening of SN 1006 in AD 1016 as recorded in the ancient Chinese literature to be true and the re-brightening was caused by the encounter either of photons or the shock wave from the SN outburst with the circumstellar thin envelope materials. Based on these considerations, and combining the observational results on the optical proper motion of the N-W limb and the radio observations of the other parts of the supernova remnant G327.6＋14.5, we re-determine the distance to SN 1006. For the photon-encounter model, the average radius of the envelope material would be 101y; and for the shock waveencounter model, the radius would be about 1 ly. We then set up four equations to solve for the distance of the SN, the initial shock speed, the expansion index for two different parts of the supernova remnant, and the real original radius of the thin envelope nebula. It is indicated that only the case of photon-encounter will lead to a reasonable result. We derived a distance of 5074 ly （1.56 kpc）, an original shock expansion velocity of 0.07 1c, an expansion index of 0.72 for the N-W limb of the SNR, and 0.76 for the other parts. We deem that the SNR evolution is still in the stage of reverse shock.展开更多
Stimulated by the recent discovery of PSR J1833-1034 in SNR G21.5-0.9 and its age parameters presented by two groups of discovery, we demonstrate that the PSR J1833- 1034 was born 2053 years ago from a supernova explo...Stimulated by the recent discovery of PSR J1833-1034 in SNR G21.5-0.9 and its age parameters presented by two groups of discovery, we demonstrate that the PSR J1833- 1034 was born 2053 years ago from a supernova explosion, the BC 48 guest star observed in the Western Han （Early Han） Dynasty by ancient Chinese. Based on a detailed analysis of the Chinese ancient record of the BC 48 guest star and the new detected physical parameters of PSR J1833-1034, agreements on the visual position, age and distance between PSR J1833- 1034 and the BC 48 guest star are obtained. The initial period/90 of PSR J1833-1034 is now derived from its historical and current observed data without any other extra assumption on P0 itself, except that the factor PP is a constant in its evolution until now.展开更多
文摘Here we extend the conservation of energy in the framework of the thin layer approximation to the asymmetrical case. Four types of interstellar mediums are analysed, in which the density follows an inverse square profile, a power law profile, an exponential profile and a toroidal profile. An analytical solution for the radius as a function of time and the polar angle in spherical coordinates is derived in the case of the inverse square profile. The analytical and numerical results are applied to two supernova remnants: SN 1987A and SN 1006. The back reaction due to the radiative losses is evaluated in the case of the inverse square profile for the surrounding medium. Two models for the image formation are presented, which explain the triple ring visible in SN 1987A and the jet feature of SN 1006.
基金supported by the Israel Science Foundationthe E.and J.Bishop Research Fund at the Technion
文摘I use recent observational and theoretical studies of type Ia supernovae(SNe Ia) to further constrain the viable SN Ia scenarios and to argue that there must be a substantial time delay between the end of the merger of the white dwarf(WD) with a companion or the end of mass accretion on to the WD and its terminal explosion. This merger/accretion to explosion delay(MED) is required to allow the binary system to lead to a more or less spherical explosion and to prevent a pre-explosion ionizing radiation. Considering these recent results and the required MED, I conclude that the core degenerate scenario is somewhat more favorable over the other scenarios, followed by the double degenerate scenario. Although the single degenerate scenario is viable as well, it is less likely to account for common(normal) SN Ia. As all scenarios require substantial MED, the MED has turned from a disadvantage of the core degenerate scenario to a challenge that theory should overcome. I hope that the requirement for a MED will stimulate the discussion of the different SN Ia scenarios and the comparison of the scenarios to each other.
基金Supported by the National Natural Science Foundation of China.
文摘We presume the re-brightening of SN 1006 in AD 1016 as recorded in the ancient Chinese literature to be true and the re-brightening was caused by the encounter either of photons or the shock wave from the SN outburst with the circumstellar thin envelope materials. Based on these considerations, and combining the observational results on the optical proper motion of the N-W limb and the radio observations of the other parts of the supernova remnant G327.6＋14.5, we re-determine the distance to SN 1006. For the photon-encounter model, the average radius of the envelope material would be 101y; and for the shock waveencounter model, the radius would be about 1 ly. We then set up four equations to solve for the distance of the SN, the initial shock speed, the expansion index for two different parts of the supernova remnant, and the real original radius of the thin envelope nebula. It is indicated that only the case of photon-encounter will lead to a reasonable result. We derived a distance of 5074 ly （1.56 kpc）, an original shock expansion velocity of 0.07 1c, an expansion index of 0.72 for the N-W limb of the SNR, and 0.76 for the other parts. We deem that the SNR evolution is still in the stage of reverse shock.
基金Supported by the National Natural Science Foundation of China.
文摘Stimulated by the recent discovery of PSR J1833-1034 in SNR G21.5-0.9 and its age parameters presented by two groups of discovery, we demonstrate that the PSR J1833- 1034 was born 2053 years ago from a supernova explosion, the BC 48 guest star observed in the Western Han （Early Han） Dynasty by ancient Chinese. Based on a detailed analysis of the Chinese ancient record of the BC 48 guest star and the new detected physical parameters of PSR J1833-1034, agreements on the visual position, age and distance between PSR J1833- 1034 and the BC 48 guest star are obtained. The initial period/90 of PSR J1833-1034 is now derived from its historical and current observed data without any other extra assumption on P0 itself, except that the factor PP is a constant in its evolution until now.
