- ID:
- ivo://CDS.VizieR/J/ApJS/181/433
- Title:
- Spectrum of ethyl formate
- Short Name:
- J/ApJS/181/433
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since methyl formate (O=CH-O-CH_3_) is found to have a high abundance in Hot molecular cores and other types of clouds in the galactic center, it is reasonable to search among such sources for detectable abundances of the more complex analog ethyl formate (O=CH-OOC_2_H_5_). Following a previous study of the millimeter-wave spectrum of ethyl formate, we have extended the analysis of the vibrational ground state of the trans and gauche conformers of ethyl formate into the submillimeter-wave range. Over 2200 new spectral lines have been measured and analyzed at frequencies up to 380GHz. Fitting the data for each conformer to a Watson A-reduced asymmetric-top Hamiltonian has allowed us to predict the frequencies and intensities of many more transitions through 380GHz.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/648/A48
- Title:
- SPIRou wavelength calibration
- Short Name:
- J/A+A/648/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SPIRou is a near-infrared (nIR) spectropolarimeter at the CFHT, covering the YJHK nIR spectral bands (980-2350nm). We describe the development and current status of the SPIRou wavelength calibration in order to obtain precise radial velocities (RVs) in the nIR. We make use of a UNe hollow-cathode lamp and a Fabry-Perot etalon to calibrate the pixel-wavelength correspondence for SPIRou. Different methods are developed for identifying the hollow-cathode lines, for calibrating the wavelength dependence of the Fabry-Perot cavity width, and for combining the two calibrators. The hollow-cathode spectra alone do not provide a sufficiently accurate wavelength solution to meet the design requirements of an internal error of <0.45m/s, for an overall RV precision of 1m/s. However, the combination with the Fabry-Perot spectra allows for significant improvements, leading to an internal error of 0.15m/s. We examine the inter-night stability, intra-night stability, and impact on the stellar RVs of the wavelength solution.
- ID:
- ivo://CDS.VizieR/J/MNRAS/404/1529
- Title:
- s-process in low-metallicity stars
- Short Name:
- J/MNRAS/404/1529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large sample of carbon-enhanced metal-poor stars enriched in s-process elements (CEMP-s) have been observed in the Galactic halo. These stars of low mass (M~0.9M_{sun}_) are located on the main-sequence or the red-giant phase, and do not undergo third dredge-up (TDU) episodes. The s-process enhancement is most plausibly due to accretion in a binary system from a more massive companion when on the asymptotic giant branch (AGB) phase (now a white dwarf). In order to interpret the spectroscopic observations, updated AGB models are needed to follow in detail the s-process nucleosynthesis. We present nucleosynthesis calculations based on AGB stellar models obtained with Frascati Raphson-Newton Evolutionary Code (FRANEC) for low initial stellar masses and low metallicities. For a given metallicity, a wide spread in the abundance of the s-process elements is obtained by varying the amount of 13C and its profile in the pocket, where the 13C({alpha}, n)16O reaction is the major neutron source, releasing neutrons in radiative conditions during the interpulse phase. We also account for the second neutron source ^22^Ne({alpha},n)^25^Mg, partially activated during convective thermal pulses.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/9
- Title:
- Stand2015 Atmospheric Chemical Network for HCNO
- Short Name:
- J/ApJS/224/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There are many open questions about prebiotic chemistry in both planetary and exoplanetary environments. The increasing number of known exoplanets and other ultra-cool, substellar objects has propelled the desire to detect life and prebiotic chemistry outside the solar system. We present an ion-neutral chemical network constructed from scratch, Stand2015, that treats hydrogen, nitrogen, carbon, and oxygen chemistry accurately within a temperature range between 100 and 30000K. Formation pathways for glycine and other organic molecules are included. The network is complete up to H6C2N2O3. Stand2015 is successfully tested against atmospheric chemistry models for HD 209458b, Jupiter, and the present-day Earth using a simple one-dimensional photochemistry/diffusion code. Our results for the early Earth agree with those of Kasting for CO_2_, H_2_, CO, and O_2_, but do not agree for water and atomic oxygen. We use the network to simulate an experiment where varied chemical initial conditions are irradiated by UV light. The result from our simulation is that more glycine is produced when more ammonia and methane is present. Very little glycine is produced in the absence of any molecular nitrogen and oxygen. This suggests that the production of glycine is inhibited if a gas is too strongly reducing. Possible applications and limitations of the chemical kinetics network are also discussed.
655. Stark broadening
- ID:
- ivo://CDS.VizieR/J/A+AS/113/579
- Title:
- Stark broadening
- Short Name:
- J/A+AS/113/579
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tables of Stark broadening profiles for the N V 6f, g, h-7f, g, h, i line complex at 4945A have been generated. Modern close-coupling techniques are used for the electron broadening while the important influence of perturbing ions is included within the framework of the model microfield method. Comparison has been made with the results of line formation calculations using approximate formulae for the Stark profiles.
- ID:
- ivo://CDS.VizieR/J/A+AS/105/245
- Title:
- Stark broadening Al XI and Si XII
- Short Name:
- J/A+AS/105/245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/542/A75
- Title:
- Stark broadening for the HeI 492.2 line
- Short Name:
- J/A+A/542/A75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The tables contain the area normalized Stark broadened spectral profiles of the HeI 492.2nm line. Doppler effect has not been included in the profiles. The first column of each table is the wavelength detuning, measured in nanometers, from the unperturbed wavelength. The other columns give the spectral profiles for different cases of perturber mass and electron temperature. Each table contains the data for a fixed electron density, ranging from 10^20^m^-3^ to 10^24^m^-3^ in different tables. Data corresponding to four different reduced masses of the emitter perturber pair, {mu}, are given in each table. The values of {mu} given in the tables are {mu}=0.8, 2.0, 4.0 and 10.0, in units of the proton mass. For each case of {mu} the profiles for different electron temperatures are given in different columns. Each table has a head giving the electron density value, and the values of {mu} and temperature corresponding to each column.
- ID:
- ivo://CDS.VizieR/J/A+A/400/791
- Title:
- Stark broadening of Be III lines
- Short Name:
- J/A+A/400/791
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a semiclassical perturbation method, we have calculated electron-, proton-, and ionized helium-impact line widths and shifts for 52 Be III multiplets as a function of temperature and perturber density. Electron temperatures are 10000K; 20000K; 50000K; 100000K; 200000K and 300000K and perturber densities are from 10^11^cm^-3^ up to 10^21^cm^-3^. The obtained results have been used for discussion of regularities and systematic trends along spectral series.
- ID:
- ivo://CDS.VizieR/J/A+AS/105/243
- Title:
- Stark broadening of BeI lines
- Short Name:
- J/A+AS/105/243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+AS/140/191
- Title:
- Stark broadening of Ca I
- Short Name:
- J/A+AS/140/191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the semiclassical perturbation approach, we have calculated electron-, proton-, He II-, Mg II-, Si II- and Fe II-impact line widths and shifts for 189 Ca I multiplets as a function of temperature and perturber density. Perturbers selected here are the main perturbers in solar atmospheres. Obtained results have been compared with the existing theoretical and experimental data.
