论文标题
原始氦-3 Redux：猎户座星云的氦同位素比
Primordial helium-3 redux: The helium isotope ratio of the Orion nebula
论文作者
论文摘要
我们报告了局部星际云之外的氦同位素比3HE/4HE的第一个直接测量，这是科学验证观测值的一部分，该观察结果是升级的低温红外梯形梯形光谱仪（CRIRES）。我们对3HE/4HE的确定是基于沿着猎户座星云中tet02 ori的亚稳态吸收。我们测量一个值为3HE/4HE =（1.77 +/- 0.13）X10^{ - 4}，假设粒子物理学和宇宙学的标准模型（3He/4he）_p =（1.257 +/-- 0.017）x10^-4。我们使用Limongi＆Chieffi（2018）的产率在质量范围M = 8-100 M_SUN和Lagarde（2011,2012,2012）中，使用Limongi＆Chieffi（2018）的产量来计算一组银河化学演化模拟，以研究这些同位素的银河系累积。我们发现，如果以原始比率（3He/4he）_p =（1.043 +/- 0.089）x10^-4初始化计算，则这些模拟同时再现了Orion和Protosolar 3HE/4HE。即使引用错误不包括模型不确定性，此确定仍与〜2sigma内的标准模型值一致。我们还使用氘（D/H），氦气（He/H）和3He/4he的当今银河系丰度来推断原始3He 3He丰度的经验限制，（3HE/H）_p <（1.09 +/- 0.18）x10^-5，同样符合标准模型值。我们指出，与非标准物理学解释差异原始7Li/h的丰度越来越困难，而不会破坏三个原始元素比率（D/H，4HE/H和3HE/4HE）与标准模型值的显着同时一致。
We report the first direct measurement of the helium isotope ratio, 3He/4He, outside of the Local Interstellar Cloud, as part of science verification observations with the upgraded CRyogenic InfraRed Echelle Spectrograph (CRIRES). Our determination of 3He/4He is based on metastable HeI* absorption along the line-of-sight towards Tet02 Ori A in the Orion Nebula. We measure a value 3He/4He=(1.77+/-0.13)x10^{-4}, which is just ~40 per cent above the primordial relative abundance of these isotopes, assuming the Standard Model of particle physics and cosmology, (3He/4He)_p = (1.257+/-0.017)x10^-4. We calculate a suite of galactic chemical evolution simulations to study the Galactic build up of these isotopes, using the yields from Limongi & Chieffi (2018) for stars in the mass range M=8-100 M_sun and Lagarde (2011,2012) for M=0.8-8 M_sun. We find that these simulations simultaneously reproduce the Orion and protosolar 3He/4He values if the calculations are initialized with a primordial ratio (3He/4He)_p=(1.043+/-0.089)x10^-4. Even though the quoted error does not include the model uncertainty, this determination agrees with the Standard Model value to within ~2sigma. We also use the present-day Galactic abundance of deuterium (D/H), helium (He/H), and 3He/4He to infer an empirical limit on the primordial 3He abundance, (3He/H)_p < (1.09+/-0.18)x10^-5, which also agrees with the Standard Model value. We point out that it is becoming increasingly difficult to explain the discrepant primordial 7Li/H abundance with non-standard physics, without breaking the remarkable simultaneous agreement of three primordial element ratios (D/H, 4He/H, and 3He/4He) with the Standard Model values.
