- ID:
- ivo://CDS.VizieR/J/ApJ/755/L10
- Title:
- Revised stellar neutron capture reactivities
- Short Name:
- J/ApJ/755/L10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A general formalism to include experimental reaction cross sections into calculations of stellar rates is presented. It also allows us to assess the maximally possible reduction of uncertainties in the stellar rates by experiments. As an example for the application of the procedure, stellar neutron capture reactivities from KADoNiS v0.3 are revised and the remaining uncertainties shown. Many of the uncertainties in the stellar rates are larger than those obtained experimentally. This has important consequences for s-process models and the interpretation of meteoritic data because it allows the rates of some reactions to vary within a larger range than previously assumed.
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- ID:
- ivo://CDS.VizieR/VI/71A
- Title:
- Revised version of the ILLSS Catalogue
- Short Name:
- VI/71A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue is a revised version of the Identification List of Lines in Stellar Spectra and now lists wavelength, spectrum, multiplet number, intensity, ionisation potential and stellar type reference for lines in the region 2951 to 13164 Angstroems. (This catalogue was announced as number III/171)
- ID:
- ivo://CDS.VizieR/J/A+A/537/A74
- Title:
- RhII oscillator strengths
- Short Name:
- J/A+A/537/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work reports oscillator strengths for transitions of astrophysical interest in singly ionized rhodium. Seventeen radiative lifetimes in Rh^+^ have been measured with the time-resolved laser-induced fluorescence technique and combined with theoretical branching fractions calculated using a relativistic Hartree-Fock model including core-polarization effects to obtain oscillator strengths. On the basis of the good agreement between theory and experiment for the lifetimes, new reliable oscillator strengths have been deduced for a set of 113 Rh II transitions in the spectral range 153-418nm.
- ID:
- ivo://CDS.VizieR/J/ApJS/190/322
- Title:
- R-matrix electron-impact excitation of Fe^13+^
- Short Name:
- J/ApJS/190/322
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate excitation parameters are required to interpret the ultraviolet and X-ray spectra of Fe^13+^. In this work, we use the autostructure code to describe the atomic structure of Fe^13+^. The 197 lowest-lying fine-structure levels of the 3s^x^3p^y^3d^z^(x+y+z=3), 3s^2^4l, and 3s3p4{s,p, and d} configurations are included along with further correlation configurations: 3s3p4f, 3p^x^3d^y^4l (x+y=2), 3l4l'4l", and 3l3l'5l". The resultant level energies, lifetimes of excited states, and oscillator strengths of transitions between these levels are assessed by comparison with available experimental data and previous calculations. Electron-impact excitation data among these lowest-lying levels are generated using the intermediate-coupling frame transformation R-matrix method. We assess the present results by comparisons with laboratory measurement for the excitation to the metastable level 3s^2^3p^2^P^o^_3/2_ and with available close-coupling calculations for other excitations. Using these data and a collisional-radiative model, we have analyzed soft X-ray and extreme-ultraviolet spectra from space satellite observations of a stellar corona and of solar flares, as well as measurements from an electron beam ion trap. We assess the contribution from Fe^13+^ emission lines in the solar and Procyon corona observations, and find and identify new lines in the X-ray region observed in the solar and Procyon coronae. The laboratory measurements also confirm that weak lines (218.177{AA} and 224.354{AA}) of Fe^13+^ contribute to the observed intensities in solar observations. The polarization effect due to the directional monoenergetic distribution of the electron energy has been taken into account in comparison with the laboratory measurements. Electron density diagnostics for the astrophysical plasma sources have been performed using the updated data so as to investigate their sensitivity to the atomic data source.
- ID:
- ivo://CDS.VizieR/J/ApJ/382/636
- Title:
- Rosseland mean free-free Gaunt factor
- Short Name:
- J/ApJ/382/636
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Rosseland mean free-free Gaunt factor of the dense high-temperature stellar plasma is calculated, based on both the accurate relativistic cross section and Sommerfeld's exact nonrelativistic cross section. A wide range of electron degeneracy is accurately taken into account. Comparison of the resulting free-free opacity with the electron conduction opacity is made.
- ID:
- ivo://CDS.VizieR/J/A+A/451/1125
- Title:
- Rotational excitation of CS
- Short Name:
- J/A+A/451/1125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present paper focuses on the calculation of new rate coefficients among the 31 first rotational levels of the CS molecule in collision with He for temperatures ranging from 10K to 300K.
- ID:
- ivo://CDS.VizieR/J/A+A/493/687
- Title:
- Rotational excitation of formaldehyde by H2
- Short Name:
- J/A+A/493/687
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rate coefficients for the rotational excitation of the ten lowest levels of ortho-H_2_CO by collisions with H_2_ molecules are computed for kinetic temperatures in the range 5-100K.
- ID:
- ivo://CDS.VizieR/J/A+A/430/1139
- Title:
- Rotational excitation of HF in collision with He
- Short Name:
- J/A+A/430/1139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report Close Coupling calculations of the rotational transitions induced in collisions between HF molecules and He atoms. We consider transitions for levels up to J=9 and for temperatures up to 300K. We use a new global 3D potential energy surface which we proposed recently and is the best available at the moment. This surface exhibits two minima associated both with linear geometries (V=-43.70cm^-1^ for He-HF and V=-25.88cm^-1^ for He-FH). Close Coupling calculations are performed in the collision energy 10^-6^ to 2000cm^-1^ interval. Our results validate the estimate, by Neufeld et al. (1997ApJ...488L.141N), of the abundance of HF in the interstellar medium which was detected recently.
- ID:
- ivo://CDS.VizieR/J/MNRAS/504/1531
- Title:
- Rotational Excitation Rates of HCO+
- Short Name:
- J/MNRAS/504/1531
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- HCO^+^ is one of the most abundant polyatomic ion in the Universe, also its presence in the planetary atmospheres and interstellar medium (ISM) makes it an interesting case to study. Low energy e^−^-HCO^+^ collisions result in rotational excitation and other molecular processes. In this study, the cross-sections for rotational transitions in HCO^+^ are evaluated for four rotational levels (j = 0, 1, 2, and 3) using the UK R-matrix method and the multichannel quantum defect theory (MQDT). The UK R-matrix method used to generate scattering matrices, through which cross-sections are computed. In past two decades, after developments and implementations of different theoretical approaches, the improved channel elimination procedure applied here is more promising to evaluate more accurate results near rotational thresholds important for the analysis of intensities of microwave region in plasma modelling. The rate coefficients are deduced from the computed cross-sections and studied over a wide electron temperature range.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/9
- Title:
- Rotational frequencies of TiO isotopologues
- Short Name:
- J/ApJ/833/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Pure rotational spectra of the rare isotopologues of titanium oxide, ^46^TiO, ^47^TiO, ^49^TiO, and ^50^TiO, have been recorded using a combination of Fourier transform millimeter-wave (FTmmW) and millimeter/submillimeter direct absorption techniques in the frequency range 62-538GHz. This study is the first complete spectroscopic characterization of these species in their X^3^{Delta}_r_ ground electronic states. The isotopologues were created by the reaction of N_2_O or O_2_ and titanium vapor, produced either by laser ablation or in a Broida-type oven, and observed in the natural Ti isotopic abundances. Between 10 and 11 rotational transitions J+1<->J were measured for each species, typically in all 3 spin-orbit ladders {Omega}=1, 2, and 3. For ^47^TiO and ^49^TiO, hyperfine structure was resolved, originating from the titanium-47 and titanium-49 nuclear spins of I=5/2 and 7/2, respectively. For the {Omega}=1 and 3 components, the hyperfine structure was found to follow a classic Lande pattern, while that for {Omega}=2 appeared to be perturbed, likely a result of mixing with the nearby isoconfigurational a^1^{Delta} state. The spectra were analyzed with a case (a) Hamiltonian, and rotational, spin-orbit, and spin-spin parameters were determined for each species, as well as magnetic hyperfine and electric quadrupole constants for the two molecules with nuclear spins. The most abundant species, ^48^TiO, has been detected in circumstellar envelopes. These measurements will enable other titanium isotopologues to be studied at millimeter wavelengths, providing Ti isotope ratios that can test models of nucleosynthesis.
