Astrophysical detection of the helium hydride ion HeH+

  title={Astrophysical detection of the helium hydride ion HeH+},
  author={Rolf G{\"u}sten and Helmut Wiesemeyer and David A. Neufeld and Karl M. Menten and Urs U. Graf and Karl Jacobs and Bernd Klein and O. Ricken and Christophe Risacher and J{\"u}rgen Stutzki},
During the dawn of chemistry1,2, when the temperature of the young Universe had fallen below some 4,000 kelvin, the ions of the light elements produced in Big Bang nucleosynthesis recombined in reverse order of their ionization potential. With their higher ionization potentials, the helium ions He2+ and He+ were the first to combine with free electrons, forming the first neutral atoms; the recombination of hydrogen followed. In this metal-free and low-density environment, neutral helium atoms… 

Comprehensive Chemistry of HeH+ in the Early Universe

The recent detection of the helium hydride ion (HeH+) in the planetary nebula NGC 7027 has inspired studies revisiting the dominant processes for its formation and destruction. Because radiative

Quantum-state–selective electron recombination studies suggest enhanced abundance of primordial HeH+

The stability of HeH+ to electron bombardment in a cryogenic storage ring suggests its enhanced primordial abundance and a pronounced decrease of the electron recombination rates for the lowest rotational states of the helium hydride ion, compared with previous measurements at room temperature.

Rydberg States of H3 and HeH as Potential Coolants for Primordial Star Formation.

The salient considerations are reviewed and some new ideas are presented, based on recent spectroscopic observations of neutral H3 Rydberg electronic state emission in the mid-infrared region, regarding the age of the universe are presented.

Insights Into Chemical Reactions at the Beginning of the Universe: From HeH+ to H3 +

This study has tried to mimic the conditions in the early Universe to show how the recombination process would have led to the formation of the first ever formed diatomic species of the Universe: HeH+, as well as the subsequent processes that would have lead to the creation of the simplest triatomic species: H3 +.

Exploring the Possibility of Identifying Hydride and Hydroxyl Cations of Noble Gas Species in the Crab Nebula Filament

The first identification of the argonium ion ( ) toward the Crab Nebula supernova remnant was proclaimed by Herschel in the submillimeter and far-infrared domains. Very recently, the discovery of the

Introduction to astrochemistry: chemical evolution from interstellar clouds to star and planet formation

That helium hydride, HeH+, should exist in astrophysical plasma was just an idea to begin with [1]. The odds that this super-ancient molecule – the first ever to have been synthesised after the Big

First molecule still animates astronomers

Study of the helium hydride ion under conditions designed to mimic those of the early Universe offers insight into the chemical composition of the Universe before formation of the first stars.

Thermal and resonant emission of dark age halos in the rotational lines of HeH+

We analyse the thermal emission and resonant scattering of CMB radiation from the dark ages halos in the rotational lines of the helium hydride ion (HeH$^{+}$), one of the first chemical compounds in

Detection of Vibrational Emissions from the Helium Hydride Ion (HeH+) in the Planetary Nebula NGC 7027

We report the detection of emission in the v = 1 − 0 P(1) (3.51629 μm) and P(2) (3.60776 μm) rovibrational lines of the helium hydride cation (HeH+) from the planetary nebula NGC 7027. These

A Molecular Candle Where Few Molecules Shine: HeHHe+

The present study provides new insights into HeHHe+ possible formation mechanisms as well as marked stability, along with the decisive role of anharmonic zero-point energies.



The Dawn of Chemistry

Within the precise cosmological framework provided by the Λ-cold dark matter model and standard Big Bang nucleosynthesis, the chemical evolution of the pregalactic gas can now be followed with

The Deuterium Chemistry of the Early Universe

The chemistry of deuterium, as well as that of hydrogen and helium, in the postrecombination era of the expanding early universe is presented. A thorough survey of all potentially important gas-phase

Search for hydrogen-helium molecular species in space

Context. Helium, the second most abundant element in the Universe, with a relative abundance of He/H ~ 1/10, has never been observed in any other form than that of a neutral atom (He) or an ion (He +

Identification of features due to H3 + in the infrared spectrum of supernova 1987A

THE molecular ion H3 + occupies a central position in theoretical models of interstellar chemistry1,2. It forms readily in hydrogen-rich interstellar gas clouds when ionized H2 reacts with neutral

Ion chemistry in the early universe - Revisiting the role of HeH+ with new quantum calculations

Aims. The role of HeH + has been newly assessed with the aid of newly calculated rates which use entirely ab initio methods, thereby allowing us to compute more accurately the relevant abundances

The formation and destruction of HeH/+/ in astrophysical plasmas

A discussion is presented of the formation and destruction mechanisms of the molecular ion HeH/sup +/ in astrophysical plasmas. Calculations are made of the steady state abundance of HeH/sup +/ in

Emission of HeH + in Nebulae

The formation and destruction processes of HeH + in nebulae are discussed, and calculations of the abundances of HeH + are presented. It is shown that for effective temperatures of the ionizing


We have measured dissociative recombination (DR) of HCl+ with electrons using a merged beams configuration at the TSR heavy-ion storage ring located at the Max Planck Institute for Nuclear Physics in

Molecules in planetary nebulae

It is shown that significant abundances of simple molecules, like H/sub 2/, H/sub 2//sup +/, HeH/sup +/, OH, and CH/sup +/, can exist in the transition zones of ionized nebulae. The dominant

Photodissociation and radiative association of HeH+ in the metastable triplet state.

It is shown that the photodissociation cross sections depend strongly on the initial vibrational state and that the effects of excited electronic states and nonadiabatic couplings cannot be neglected.