- ID:
- ivo://CDS.VizieR/J/A+A/629/A35
- Title:
- Succinonitrile and excited states spectroscopy
- Short Name:
- J/A+A/629/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dinitriles with a saturated hydrocarbon skeleton and a -CN group at each end can have large electric dipole moments. Their formation can be related to highly reactive radicals such as CH_2_CN, C_2_N or CN. Thus, these saturated dinitriles are potential candidates to be observed in the ISM. Our goal is the investigation of the rotational spectrum of one of the simplest dinitriles NC-CH_2_-CH_2_-CN, succinonitrile, whose actual rotational parameters are not precise enough to allow its detection it in the ISM. In addition, the rotational spectra for its vibrational excited states will be analyzed. The rotational spectra of succinonitrile was measured in the frequency range 72-116.5GHz using a new broadband millimeter-wave spectrometer based on radio astronomy receivers with Fast Fourier Transform backends. The identification of the vibrational excited states of succinonitrile was supported by high-level ab initio calculations on the harmonic and anharmonic force fields. A total of 459 rotational transitions with maximum values of J and Ka quantum numbers 70 and 14, respectively, were measured for the ground vibrational state of succinonitrile. The analysis allowed us to accurately determine the rotational, quartic and sextic centrifugal distortion constants. Up to eleven vibrational excited states, resulted from the four lowest frequency vibrational modes nu13, nu12, nu24 and nu23 were identified. In addition to the four fundamental modes, we observed overtones together with some combination states. The rotational parameters for the ground state were employed to unsuccessfully search for succinonitrile in the cold and warm molecular clouds Orion KL, Sgr B2(N), B1-b and TMC-1,using the spectral surveys captured by IRAM 30m at 3mm and the Yebes 40m at 1.3cm and 7mm.
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- ID:
- ivo://CDS.VizieR/J/A+A/655/A74
- Title:
- Sulfur ion irradiation experiments
- Short Name:
- J/A+A/655/A74
- Date:
- 10 Mar 2022 07:29:19
- Publisher:
- CDS
- Description:
- Sulfur (S) is of high interest in context of (astro)chemical evolution and habitability. However, the origin of S-bearing organic compounds in the Solar System is still not well-constrained. We tested by laboratory experiments whether complex organosulfur compounds can be formed when surfaces of icy Solar System bodies are submitted to high-energy S ions. Methods. Non-S-bearing organic residues, formed during the processing of astrophysical H_2_O:CH_3_ OH:NH_3_-bearing ice analogs, were irradiated with 105 keV-S 7+ ions at 10K and analyzed by high-resolving FT-ICR-MS. Resulting data were comprehensively analyzed, including the tools of network analysis. Out of many thousand detected compounds, 16% contain at least one sulfur atom (organosulfur (CHNOS) compounds), as verified via isotopic fine structures. These residue-related organosulfur compounds are different to the ones formed during S ion irradiation of ices at 10K. Furthermore, insoluble, apolar material was formed during the sulfur irradiation of residues. Potential organosulfur precursors (CHNO molecules) were identified by means of chemical network analysis. The finding of organosulfur compounds formed by sulfur irradiation of organic residues sheds new light into the rich and complex pristine organosulfur chemistry in the Solar System, as discussed here in context of current and future space missions. These results indicate that space weathering of Solar System bodies may lead to the formation of organosulfur compounds.
- ID:
- ivo://CDS.VizieR/J/A+A/533/A87
- Title:
- Sulphur ions iso-electronic sequence
- Short Name:
- J/A+A/533/A87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present our calculated data including energy levels, radiative decay rates and effective collision strengths for all the transitions among fine-structure levels of n=3 or 4 configurations, for four iso-nuclear ions, viz S^8+^, S^9+^, S^10+^ and S^11+^.
- ID:
- ivo://CDS.VizieR/J/ApJS/208/27
- Title:
- Sun and HD 84937 TiII log(gf) and abundances
- Short Name:
- J/ApJS/208/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Atomic transition probability measurements for 364 lines of Ti II in the UV through near-IR are reported. Branching fractions from data recorded using a Fourier transform spectrometer (FTS) and a new echelle spectrometer are combined with published radiative lifetimes to determine these transition probabilities. The new results are in generally good agreement with previously reported FTS measurements. Use of the new echelle spectrometer, independent radiometric calibration methods, and independent data analysis routines enables a reduction of systematic errors and overall improvement in transition probability accuracy over previous measurements. The new Ti II data are applied to high-resolution visible and UV spectra of the Sun and metal-poor star HD 84937 to derive new, more accurate Ti abundances. Lines covering a range of wavelength and excitation potential are used to search for non-LTE effects. The Ti abundances derived using Ti II for these two stars match those derived using Ti I and support the relative Ti/Fe abundance ratio versus metallicity seen in previous studies.
- ID:
- ivo://CDS.VizieR/J/A+A/452/1113
- Title:
- S V effective collision strengths
- Short Name:
- J/A+A/452/1113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Effective collision strengths are presented in this table for all the transitions among the 26 fine-structure levels arising from the 14 lowest LS states of S V, i.e. those with configurations: (2p^6^)3s^2^, 3s3p, 3p^2^, 3s3d, 3s4s, 3p3d. The effective collision strengths have been calculated using the R-matrix method. Each fine-structure level is assigned an index number ranging from 1 to 26, which are noted in the paper as Table 5. The index values are used here in Table 7 to refer to particular transitions, eg. Index 2-8 denotes the 2p(6)3s3p 3PO(J=0)- 2p(6)3p^2^ 3PE(J=1) transition. The effective collision strengths for each transition are presented for electron temperatures ranging from log10(T)=4.0 to log10(T)=6.0 in steps of 0.1.
696. Swan system of C2
- ID:
- ivo://CDS.VizieR/J/ApJS/169/472
- Title:
- Swan system of C2
- Short Name:
- J/ApJS/169/472
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The C2 Swan system (d ^3^{Pi}_g_-a ^3^{Pi}_u_) was observed in emission for the {Delta}v=-3 to {Delta}v=+2 sequences in the 14000-24000cm^-1^ spectral range using a Fourier transform spectrometer. We carried out a global simultaneous fit by including a wide range of vibrational states. A total of 34 bands with v'=0-10 and v"=0-9 were rotationally assigned. Numerous discrepancies were found in the assignments and in the measured transition wavenumbers between the new measurements and previous results. Most of the measured transition wavenumbers and their assignments for relatively low-v bands agreed with published data. On the contrary, for high-v bands our line positions and assignments disagreed with the tabulated literature values. In particular, the lines of six bands involving the levels with v'=4, 5, and 6 are almost completely different from the previous work. Major sources of the disagreement are thought to be line congestion and perturbations found in these bands. From the analysis, perturbations for v'=0, 1, 2, 4, 6, 8, 9, and 10 in the d ^3^{Pi}_g_ state were identified. A study of these rotational perturbations suggest that some of them are likely caused by interactions with high-v levels of the b ^3^{Sigma}^-^_g_ state.
- ID:
- ivo://CDS.VizieR/J/A+A/574/A29
- Title:
- Tc IV, Tc V and Tc VI oscillator strengths
- Short Name:
- J/A+A/574/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The discovery of technetium (Tc) in the atmospheres of red giants by Merrill (1952ApJ...116...21M) constituted convincing proof that s-process nucleosynthesis is indeed occurring in evolved stars. In principle, Tc should still be present in the atmospheres of hot post-AGB stars and (pre-) white dwarfs although, due to radioactive decay, it should be present in decreasing quantities along post-AGB evolution. The recent discovery of a large number of trans-iron group elements in hot white dwarfs with atomic numbers in the range A=30-56 (Zn to Ba) raises the prospect that Tc (A=43) may also be detected. However, this is currently not feasible because no atomic data exist for ionization stages beyond TcII. As an initial step, we calculated atomic energy levels and oscillator strengths of Tc IV-VI and used these data to compute non-local thermodynamic equilibrium (NLTE) model atmospheres to estimate at which minimum abundance level Tc could be detected. We show that Tc lines can be found in ultraviolet spectra of hot white dwarfs provided Tc is as abundant as other detected trans-Fe elements. We find that radiative levitation can keep Tc in large, easily detectable quantities in the atmosphere. A direct identification of Tc lines is still not feasible because wavelength positions cannot be computed with necessary precision. Laboratory measurements are necessary to overcome this problem. Our results suggest that such efforts are beneficial to the astrophysical community.
- ID:
- ivo://CDS.VizieR/J/ApJ/761/166
- Title:
- Terrestrial exoplanet atmospheres. I.
- Short Name:
- J/ApJ/761/166
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive photochemistry model for exploration of the chemical composition of terrestrial exoplanet atmospheres. The photochemistry model is designed from the ground up to have the capacity to treat all types of terrestrial planet atmospheres, ranging from oxidizing through reducing, which makes the code suitable for applications for the wide range of anticipated terrestrial exoplanet compositions. The one-dimensional chemical transport model treats up to 800 chemical reactions, photochemical processes, dry and wet deposition, surface emission, and thermal escape of O, H, C, N, and S bearing species, as well as formation and deposition of elemental sulfur and sulfuric acid aerosols. We validate the model by computing the atmospheric composition of current Earth and Mars and find agreement with observations of major trace gases in Earth's and Mars' atmospheres. We simulate several plausible atmospheric scenarios of terrestrial exoplanets and choose three benchmark cases for atmospheres from reducing to oxidizing. The most interesting finding is that atomic hydrogen is always a more abundant reactive radical than the hydroxyl radical in anoxic atmospheres. Whether atomic hydrogen is the most important removal path for a molecule of interest also depends on the relevant reaction rates. We also find that volcanic carbon compounds (i.e., CH_4_ and CO_2_) are chemically long-lived and tend to be well mixed in both reducing and oxidizing atmospheres, and their dry deposition velocities to the surface control the atmospheric oxidation states. Furthermore, we revisit whether photochemically produced oxygen can cause false positives for detecting oxygenic photosynthesis, and find that in 1 bar CO_2_-rich atmospheres oxygen and ozone may build up to levels that have conventionally been accepted as signatures of life, if there is no surface emission of reducing gases. The atmospheric scenarios presented in this paper can serve as the benchmark atmospheres for quickly assessing the lifetime of trace gases in reducing, weakly oxidizing, and highly oxidizing atmospheres on terrestrial exoplanets for the exploration of possible biosignature gases.
- ID:
- ivo://CDS.VizieR/J/A+A/549/A96
- Title:
- The mm and sub-mm spectra of 13C-glycolaldehydes
- Short Name:
- J/A+A/549/A96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Glycolaldehyde (CH_2_OHCHO) is the simplest sugar and an important intermediate in the path toward forming more complex biologically relevant molecules. Astronomical surveys of interstellar molecules, such as those that are being available with the very sensitive ALMA telescope, require preliminary laboratory investigations of the microwave and submillimeter-wave spectra of molecular species, including new isotopologues, to identify these in the interstellar media.
- ID:
- ivo://CDS.VizieR/J/ApJ/700/720
- Title:
- The 236.6-5400.0nm spectrum of CrI
- Short Name:
- J/ApJ/700/720
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Precision laboratory measurements are presented for 1963 CrI lines spanning the near-ultraviolet into the thermal infrared. Classifications, based on the analysis by Kiess (1953, J. Res. Natl Bur. Stand., 51, 247), are presented. The measurements were obtained from Fourier transform spectra in the archives of the National Solar Observatory.
