Cosmic Chemical Evolution Based on the Hierarchical Galaxy Formation Scenario

基于分层星系形成情景的宇宙化学演化

• 批准号: 08640336
• 负责人: TSUJIMOTO Takuji
• 金额: $ 0.26万
• 依托单位: National Astronomical Observatory
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08640336/
• 关键词: Supernova; Initial Mass Function; Ia型超新星; 化学進化; 初期質量関数; 元素合成

Oxygen to iron abundance ratios of metal-poor stars provide information on nucleosynthesis yields from massive stars which end in Type II supernova explosions. Using a standard model of chemical evolution of the Galaxy we have reproduced the solar neighborhood abundance data and estimated the oxygen and iron yields of genuine SN II origin. The estimated yields are compared with the theoretical yields to derive the relation between the lower and upper mass limits in each generation of stars and the IMF slope. Independently of this relation, we furthermore derive the relation between the lower mass linit and the IMF slope from the stellar mass to light ratio in the solar neighborhood. These independent relations unambiguously determine the upper mass limit of m<@D2u@>D2=50(]SY.+-。[)10 M<@D2(]SY.sun.[)@>D2 and the IMF slope index of 1.3-1.6 above 1 M<@D2(]SY.sun.[)@>D2. This upper mass limit corresponds to the mass beyond which stars end as black holes without ejecting processed matter into the interstellar medium. we also find that the IMF slope index below 0.5 M<@D2(]SY.sun.[)@>D2 cannot be much shallower than 0.8.

贫金属恒星的氧铁丰度比提供了大质量恒星核合成产率的信息，这些恒星最终会发生II型超新星爆炸。利用银河系化学演化的标准模型，我们重现了太阳附近的丰度数据，并估计了真正的SN II起源的氧和铁产量。将估算的产额与理论产额进行比较，导出每一代恒星的质量上限和下限与IMF斜率之间的关系。独立于这个关系，我们进一步推导出低质量极限和IMF斜率之间的关系，从恒星的质量，在太阳附近的光比。这些独立关系明确地确定了m<@D2u@>D2=50（]SY ±-的质量上限。[)10 M<@D2（]SY.sun. [）@> D_2，1 M以上IMF斜率指数为1.3-1.6。[）@>D2.这个质量上限对应于恒星在没有将处理过的物质喷射到星际介质中的情况下作为黑洞结束的质量。我们还发现，IMF斜率指数在0.5M以下<@D2（] SY. sun。[）@>D2不能比0.8浅得多。

项目成果

M.Mori,Y.Yoshii,T.Tsujimoto,K.Nomoto: "The Evolution of Dwarf Galaxies with Star Formation in Outward Propagating Supershell" The Astrophysical Journal. (in press). (1997)

M.Mori、Y.Yoshii、T.Tsujimoto、K.Nomoto：“矮星系的演化与向外传播的超壳层中恒星的形成”《天体物理学杂志》。

Takuji Tsujimoto: "The Absolute Magnitude of RR Lyme Stars Derived from the Hipparcos Catalogue" The Astrophysical Journal Letters. 492. L79-L82 (1998)

Takuji Tsujimoto：“从依巴谷星表得出的 RR 莱姆星的绝对星等”《天体物理学杂志快报》。

Takuji Tsujimoto: "The Absolute Magnitude of RR Lyrae Stars Derived from the Hipporcos Catalogue" The Astrophysical Journal Letters. 492. L79-L82 (1998)

Takuji Tsujimoto：“来自河马星表的 RR 天琴座恒星的绝对星等”《天体物理学杂志快报》。

Takuji Tsujimoto: "A New Approach to Determine the Initial Mass Function Deduced from the Chemical Evolution" The Astrophysical Journal. 483. 228-234 (1997)

Takuji Tsujimoto：“一种确定从化学演化推导出的初始质量函数的新方法”《天体物理学杂志》。

Takuji Tsujimoto: "A New Approach to Determine the Initial Mass Function Deduced from the Chemical Evolution" The Astrophysical Journal. Vol.483. 228-234 (1997)

Takuji Tsujimoto：“一种确定从化学演化推导出的初始质量函数的新方法”《天体物理学杂志》。