The cosmological density of baryons from observations of 3He+ in the Milky Way

  title={The cosmological density of baryons from observations of 3He+ in the Milky Way},
  author={T. M. Bania and Robert T. Rood and Dana. S. Balser},
Primordial nucleosynthesis after the Big Bang can be constrained by the abundances of the light elements and isotopes 2H, 3He, 4He and 7Li (ref. 1). The standard theory of stellar evolution predicts that 3He is also produced by solar-type stars, so its abundance is of interest not only for cosmology, but also for understanding stellar evolution and the chemical evolution of the Galaxy. The 3He abundance in star-forming (H II) regions agrees with the present value for the local interstellar… 

Galactic evolution of D, 3He and 4He

  • D. Romano
  • Physics
    Proceedings of the International Astronomical Union
  • 2009
Abstract The uncertainties which still plague our understanding of the evolution of the light nuclides D, 3He and 4He in the Galaxy are described. Measurements of the local abundance of deuterium

The Milky Way 3-Helium Abundance

Abstract We are making precise determinations of the abundance of the light isotope of helium, 3He. The 3He abundance in Milky Way sources impacts stellar evolution, chemical evolution, and

On the Baryometric Status of 3He

Recent observations by Bania et al. measure 3He versus oxygen in Galactic H II regions, finding that 3He/H is within a factor of 2 of the solar abundance for [O/H] ≳ -0.6. These results are


Recent spectroscopic observations of metal poor stars have indicated that both 7Li and 6Li have abundance plateaus as a function of the metallicity. Abundances of 7Li are about a factor three lower


Big Bang nucleosynthesis (BBN) theory predicts the abundances of the light elements D, 3He, 4He, and 7Li produced in the early universe. The primordial abundances of D and 4He inferred from

Big-Bang Nucleosynthesis and Primordial Lithium Abundance Problem

Prediction of the primordial abundances of elements in the big-bang nucleosynthesis (BBN) is one of the three strong evidences for the big bang model. Precise knowledge of the baryon-to-photon ratio

Primordial Helium-3 Redux: The Helium Isotope Ratio of the Orion Nebula

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

Do All Low-Mass Stars Undergo Extra Mixing Processes?

Standard stellar evolution models that only consider convection as a physical process to mix material inside of stars predict the production of significant amounts of 3He in low-mass stars (M < 2 M

Big bang nucleosynthesis

Abstract We present an overview of the standard model of big bang nucleosynthesis (BBN), which describes the production of the light elements in the early universe. The theoretical prediction for the



Detection of helium-3 in a planetary nebula

HELIUM–3 is created by cosmological nucleosynthesis with an abundance 3He/H ≈ 2 x 10−5 (ref. 1), but then augmented by stellar nucleosynthesis. Stars comparable in mass to the Sun should contribute a

3He in the Milky Way Interstellar Medium: Abundance Determinations

We are making precise determinations of the abundance of the light isotope of helium, 3He. The 3He abundance in Milky Way sources provides strong constraints for theories of stellar evolution,

3He in Planetary Nebulae: A Challenge to Stellar Evolution Models

The discrepancy between the observed abundances of 3He in the interstellar medium and those predicted by stellar and Galactic chemical evolution remains largely unexplained. In this paper, we attempt

The 3He Abundance in Planetary Nebulae

We report measurements of the abundance of 3He for a sample of six Galactic planetary nebulae: IC 289, NGC 3242, NGC 6543, NGC 6720, NGC 7009, and NGC 7662. Based on observations of the 8.665 GHz

Helium-3: Status and Prospects

We report on our continuing efforts to determine 3He abundances in H II regions and planetary nebulae. Our detections of 3He in some PNe show that some stars produce large amounts of 3He. However the

Lithium abundance at the formation of the Galaxy

The observed abundance of lithium in population I stars (young stars)1 seems to have been stable during the past 5 × 109 yr (ref. 2). This stability has been used previously1,3 to estimate the

Mixing in Stars and the Evolution of the 3He Abundance

We first recall the observational and theoretical facts that constitute the so-called 3He problem. We then review the chemical anomalies that could be related to the destruction of 3He in red giants

The Primordial Abundance of 4He Revisited

We use a sample of 45 low-metallicity H II regions to determine the primordial helium abundance Yp with a precision of better than 1%. The data includes new spectrophotometric observations of 15 blue

The Primordial Abundance of 4He: An Update

We include new data in an updated analysis of helium in low-metallicity extragalactic H II regions with the goal of deriving the primordial abundance of 4He (YP). We show that the new observations of

Stellar production as a source of /sup 3/He in the interstellar medium. [abundance]

Low-mass stars produce substantial amounts of /sup 3/He which is mixed into the convective envelope when the stars become giants. There is strong evidence that a large fraction of this envelope is