Related papers: Fate and detectability of rare gas hydride ions in…
During the dawn of chemistry when the temperature of the young Universe had fallen below $\sim$4000 K, the ions of the light elements produced in Big Bang nucleosynthesis recombined in reverse order of their ionization potential. With its…
We report the detection of emission in the v=1-0 P(1) (3.51629 micron) and P(2) (3.60776 micron) rovibrational lines of the helium hydride cation (HeH+) from the planetary nebula NGC 7027. These detections were obtained with the iSHELL…
A near-infrared spectrum of nova V1716 Scorpii (PNV J17224490-4137160), a recent bright (V_max = 7.3 mag), Fermi-LAT detected gamma-ray source, was modeled using the photoionization code CLOUDY. Abundances were estimated for He, C, N, O,…
The sheer interstellar abundance of helium makes any bound molecules or complexes containing it of potential interest for astrophysical observation. This work utilizes high-level and trusted quantum chemical techniques to predict the…
In the early universe, following the nucleosynthesis, conditions were right for recombination processes to take place yielding neutral atoms H, He and Li. The understanding so far in astrophysics is that the first molecule to be formed was…
HeH$^+$ belongs to the class of "reactive" ions that can be destroyed so quickly that chemical formation and destruction rates may compete with inelastic rates and should be considered when solving the statistical equilibrium equations.…
The cosmic abundance of hydrides depends critically on high-energy UV, X-ray, and particle irradiation. Here we study hydrides in star-forming regions where irradiation by the young stellar object can be substantial, and density and…
The first identification of the argonium ion (ArH+) towards the Crab Nebula supernova remnant was proclaimed by the Herschel in the sub-millimeter and far-infrared domain. Very recently the discovery of the hydro-helium cation (HeH+) in the…
We report the first detections of OH$^+$ emission in planetary nebulae (PNe). As part of an imaging and spectroscopy survey of 11 PNe in the far-IR using the PACS and SPIRE instruments aboard the Herschel Space Observatory, we performed a…
Context: Hydrides of the most abundant heavier elements are fundamental molecules in cosmic chemistry. Some of them trace gas irradiated by UV or X-rays. Aims: We explore the abundances of major hydrides in W3 IRS5, a prototypical region of…
Type Ia supernovae are understood to arise from the thermonuclear explosion of a carbon-oxygen white dwarf, yet the evolutionary mechanisms leading to such events remain unknown. Many proposed channels, including the classical…
From four independent calculations using three different theoretical approaches, rate coefficients for the formation of HeH$^+$ via the radiative association of He$^+$ and H were computed. Good agreement is found between our new…
We present deep echelle spectrophotometry of the brightest emission-line knots of the star-forming galaxies He 2-10, Mkn 1271, NGC 3125, NGC 5408, POX 4, SDSS J1253-0312, Tol 1457-262, Tol 1924-416 and the HII region Hubble V in the Local…
The Helix Nebula (NGC 7293) is the closest planetary nebulae. Therefore, it is an ideal template for photochemical studies at small spatial scales in planetary nebulae. We aim to study the spatial distribution of the atomic and the…
The direct detection of a stellar system that explodes as a Type Ia supernova (SN Ia) has not yet been successful. Various indirect methods have been used to investigate SN Ia progenitor systems but none have produced conclusive results. A…
We present VLT UVES echelle spectrophotometry of the Orion nebula in the 3100 to 10400 A range. We have measured the intensity of 555 emission lines, many of them corresponding to permitted lines of different heavy-element ions. This is the…
Stellar explosions such as novae and supernovae produce most of the heavy elements in the Universe. Although the onset of novae from runaway thermonuclear fusion reactions on the surface of a white dwarf in a binary star system is…
Classical and recurrent nova explosions occur on top of white dwarfs accreting H-rich matter from a companion main sequence or red giant star, in a close binary system. In the recent years, since the launch of the Fermi gamma-ray satellite…
We present the first detection of gas phase S2H in the Horsehead, a moderately UV-irradiated nebula. This confirms the presence of doubly sulfuretted species in the interstellar medium and opens a new challenge for sulfur chemistry. The…
We present results of near-infrared (near-IR) $JHK$ (1.07 - 2.5 $\mu$m) spectroscopic and photometric observations of Nova V476 Scuti (V476 Sct) which was discovered in outburst in 2005 September. The near-IR observations of the nova…