- ID:
- ivo://CDS.VizieR/J/A+A/622/A82
- Title:
- n-propyl cyanide vibrational states
- Short Name:
- J/A+A/622/A82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectra of four low-lying vibrational states of both anti and gauche conformers of n-propyl cyanide were previously measured and analyzed in two spectral windows between 36 and 127GHz. All states were then identified in a spectral line survey called Exploring Molecular Complexity with ALMA (EMoCA) toward Sagittarius B2(N) between 84.1 and 114.4GHz with the Atacama Large Millimeter/Submillimeter Array (ALMA) in its Cycles 0 and 1. We wanted to complete the measurements and analysis up to 506GHz to provide accurate predictions over a much wider range of frequencies, quantum numbers and energies. We recorded new laboratory spectra between 150-270GHz and between 310-506GHz. We carried out analysis over the whole range of measurements available from 36GHz. For the gauche conformer a large number of both a- and b- type transitions were measured, for the anti conformer transitions were predominantly, but not exclusively, a- type We hence improved molecular parameters for the ground state of both anti- and gauche- n-propyl cyanide and for excited vibrational states of the gauche-conformer (v30=1, v29=1, v28=1, v30=2) and anti-conformer (v30=1, v18=1, v29=1, v30=2) with high order coupling parameter determined between v18=1 and v30=2. Parameters are published for the first time for v18=v30=1 for the anti conformer and for v29=v30=1 for the gauche conformer. In total 15385 lines have been incorporated in the fits and should allow good predictions for unperturbed lines over the whole operating range of radio-telescopes. Evidence is found for vibrational coupling for some levels above 380GHz. The coupling between v30=2 and v18=1 of the anti conformer has been well characterized. An additional list of 740 lines showing probable but as yet unidentified coupling has been provided for astrophysical identification.
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- ID:
- ivo://CDS.VizieR/J/ApJ/854/18
- Title:
- Nucleosynthesis of p nuclides
- Short Name:
- J/ApJ/854/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The production of the heavy stable proton-rich isotopes between ^74^Se and ^196^Hg-the p nuclides-is due to the contribution from different nucleosynthesis processes, activated in different types of stars. Whereas these processes have been subject to various studies, their relative contributions to Galactic chemical evolution (GCE) are still a matter of debate. Here we investigate for the first time the nucleosynthesis of p nuclides in GCE by including metallicity and progenitor mass-dependent yields of core-collapse supernovae (ccSNe) into a chemical evolution model. We used a grid of metallicities and progenitor masses from two different sets of stellar yields and followed the contribution of ccSNe to the Galactic abundances as a function of time. In combination with previous studies on p-nucleus production in thermonuclear supernovae (SNIa), and using the same GCE description, this allows us to compare the respective roles of SNeIa and ccSNe in the production of p-nuclei in the Galaxy. The {gamma} process in ccSN is very efficient for a wide range of progenitor masses (13M_{sun}_-25M_{sun}_) at solar metallicity. Since it is a secondary process with its efficiency depending on the initial abundance of heavy elements, its contribution is strongly reduced below solar metallicity. This makes it challenging to explain the inventory of the p nuclides in the solar system by the contribution from ccSNe alone. In particular, we find that ccSNe contribute less than 10% of the solar p nuclide abundances, with only a few exceptions. Due to the uncertain contribution from other nucleosynthesis sites in ccSNe, such as neutrino winds or {alpha}-rich freeze out, we conclude that the light p-nuclides ^74^Se, ^78^Kr, ^84^Sr, and ^92^Mo may either still be completely or only partially produced in ccSNe. The {gamma}-process accounts for up to twice the relative solar abundances for ^74^Se in one set of stellar models and ^196^Hg in the other set. The solar abundance of the heaviest p nucleus ^196^Hg is reproduced within uncertainties in one set of our models due to photodisintegration of the Pb isotopes ^208,207,206^Pb. For all other p nuclides, abundances as low as 2% of the solar level were obtained.
- ID:
- ivo://CDS.VizieR/J/ApJ/662/750
- Title:
- {nu}9 fundamental band of ethane
- Short Name:
- J/ApJ/662/750
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The {nu}9 fundamental band of ethane occurs in the 12um region. It is the strongest band of ethane in a terrestrial window in the thermal infrared and is commonly used to determine ethane's abundance in the atmospheres of the Jovian planets and comets and to determine their temperature. Precise and accurate absolute intensities of this band are crucial for correct interpretation of recent Cassini observations of ethane spectra in the atmospheres of Saturn and Titan, as well as of Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) observations in the terrestrial atmosphere. Using a spectrum of the {nu}9 band of ethane recorded at 278K at the Pacific Northwest National Laboratory, we show that the line parameters available in the HITRAN and GEISA databases do not allow reproduction of the experimental data to within their accuracy.
- ID:
- ivo://CDS.VizieR/J/ApJS/225/24
- Title:
- NuGrid stellar data set I. Yields from H to Bi
- Short Name:
- J/ApJS/225/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide a set of stellar evolution and nucleosynthesis calculations that applies established physics assumptions simultaneously to low- and intermediate-mass and massive star models. Our goal is to provide an internally consistent and comprehensive nuclear production and yield database for applications in areas such as presolar grain studies. Our non-rotating models assume convective boundary mixing (CBM) where it has been adopted before. We include 8 (12) initial masses for Z=0.01 (0.02). Models are followed either until the end of the asymptotic giant branch phase or the end of Si burning, complemented by simple analytic core-collapse supernova (SN) models with two options for fallback and shock velocities. The explosions show which pre-SN yields will most strongly be effected by the explosive nucleosynthesis. We discuss how these two explosion parameters impact the light elements and the s and p process. For low- and intermediate-mass models, our stellar yields from H to Bi include the effect of CBM at the He-intershell boundaries and the stellar evolution feedback of the mixing process that produces the ^13^C pocket. All post-processing nucleosynthesis calculations use the same nuclear reaction rate network and nuclear physics input. We provide a discussion of the nuclear production across the entire mass range organized by element group. The entirety of our stellar nucleosynthesis profile and time evolution output are available electronically, and tools to explore the data on the NuGrid VOspace hosted by the Canadian Astronomical Data Centre are introduced.
- ID:
- ivo://CDS.VizieR/J/ApJ/880/138
- Title:
- Observed transitions of CH_3_OH and CH_3_CHO
- Short Name:
- J/ApJ/880/138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IRAM 30m Observations toward eight protostellar outflow sources were taken in the 96-176GHz range. Transitions of CH_3_OH and CH_3_CHO were detected in seven of them. The integrated emissions of the transitions of each species that fell into the observed frequency range were measured and fit using RADEX and LTE models. Column densities and gas properties inferred from this fitting are presented. The ratio of the A and E-type isomers of CH_3_OH indicates that the methanol observed in these outflows was formed on the grain surface. Both species demonstrate a reduction of terminal velocity in their line profiles in faster outflows, indicating destruction in the post-shock gas phase. This destruction, and a near constant ratio of the CH_3_OH and CH_3_CHO column densities, imply it is most likely that CH_3_CHO also forms on the grain surface.
- ID:
- ivo://CDS.VizieR/J/A+A/406/L47
- Title:
- 17OH spin-rotation transition frequencies
- Short Name:
- J/A+A/406/L47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The frequencies and line strengths of the ^2^{Pi}_3/2_ J=5/2-3/2 rotational transition of ^17^OH have been calculated from an analysis of its far-infrared laser magnetic resonance spectrum. These results have been used to make the first detection of a pure rotational transition of ^17^OH in the ISM. Two resolved components of this transition appear in absorption towards the giant molecular cloud Sagittarius B2, which was observed at a spectral resolution of 33km/s with the Fabry-Perot mode of the ISO Long Wavelength Spectrometer. The corresponding transition of ^18^OH was also observed and its line shape was modelled using HI measurements. The ^18^O/^17^O ratio of 3.5 was then used to compare this with the observed ^17^OH line shape.
- ID:
- ivo://CDS.VizieR/J/A+AS/137/157
- Title:
- O III recombination coefficients
- Short Name:
- J/A+AS/137/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We calculate effective recombination coefficients for the formation of the 5g-4f lines of O III in the intermediate coupling scheme. Photoionization data for the 5g levels calculated using the R-matrix method are used to derive their recombination coefficients. Cascading from higher states is included, allowing for the effects of finite electron density in a hydrogenic approximation. We explicitly include the distribution of population between the two ground levels of O^3+^ in the calculation of the line intensities. The results are presented as a simple programmable formula allowing the calculation of recombination line intensities for electron temperatures, T_e_ in the range 5000-20000K and electron densities, N_e_ in the range 10^2^-10^6^cm^-3^.
- ID:
- ivo://CDS.VizieR/J/A+A/434/773
- Title:
- O II Stark broadening parameters
- Short Name:
- J/A+A/434/773
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a modified semiempirical approach, we have calculated Stark broadening full widths at half maximum for 25 OII multiplets for temperatures from 5000K up to 80000K using the needed oscillator strengths from the sophisticated atomic structure data base TOPbase. Then we compared our results with experimental data for 41 OII spectral lines and with the available semi-classical calculations to test the applied method and the accuracy of the results obtained.
- ID:
- ivo://CDS.VizieR/J/ApJS/166/634
- Title:
- OIV Effective collision strength
- Short Name:
- J/ApJS/166/634
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Electron collision excitation strengths and rates for infrared and ultraviolet lines arising from transitions between the fine-structure levels of the 2s^2^2p, 2s2p^2^, 2p^3^, 2s^2^3s, 2s^2^3p, 2s^2^3d, 2s2p3s, 2s2p3p, 2s2p3d, 2s^2^4s, and 2s^2^4p configurations of OIV have been calculated using Breit-Pauli R-matrix approach. Configuration-interaction wave functions have been used for an accurate representation of target levels. These wave functions give excitation energies that are in close agreement with experiment. Oscillator strengths and transition probabilities for UV and EUV lines compare very well with previous calculations. The Rydberg series of resonances converging to the excited levels are explicitly included in the scattering calculation and are found to make substantial contribution to collision strengths. The effective collision strengths are obtained by integrating total collision strengths over a Maxwellian distribution of electron energies, and these are presented over a wide temperature range suitable for modeling of astrophysical plasmas. Significant qualitative and quantitative differences with earlier results of effective collision strengths are noted.
- ID:
- ivo://CDS.VizieR/J/A+A/486/1053
- Title:
- O IV radiative and excitation rates
- Short Name:
- J/A+A/486/1053
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we report calculations for energy levels, radiative rates, and excitation rates for transitions in O IV. The GRASP (general-purpose relativistic atomic structure package) and FAC (flexible atomic code) we adopted for calculating energy levels and radiative rates, and the Dirac atomic R-matrix code (DARC) used to determine the excitation rates. Oscillator strengths and radiative rates are reported for all E1, E2, M1, and M2 transitions among the lowest 75 levels of O IV. Additionally, lifetimes are reported for all levels and comparisons made with those available in the literature. Finally, effective collision strengths are reported for all transitions over a wide temperature range below 10^6^K. Comparisons are made with earlier results and the accuracy of the data is assessed.
