- ID:
- ivo://CDS.VizieR/J/ApJS/211/5
- Title:
- Improved line data for the Swan system ^12^C^13^C
- Short Name:
- J/ApJS/211/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new, accurate predictions for rotational line positions, excitation energies, and transition probabilities of the ^12^C^13^C isotopologue Swan d^3^{Pi}-a^3^{Pi} system 0-0, 0-1, 0-2, 1-0, 1-1, 1-2, 2-0, 2-1, and 2-2 vibrational bands. The line positions and energy levels were predicted through new analyses of published laboratory data for the ^12^C^13^C lines. Transition probabilities were derived from recent computations of transition dipole moments and related quantities. The ^12^C^13^C line data were combined with similar data for ^12^C_2_, reported in a companion paper (2013JQSRT.124...11B), and applied to produce synthetic spectra of carbon-rich metal-poor stars that have strong C_2_ Swan bands. The matches between synthesized and observed spectra were used to estimate band head positions for a few of the ^12^C^13^C vibrational bands and to verify that the new computed line data match observed spectra. The much weaker C_2_ lines of the bright red giant Arcturus were also synthesized in the band head regions.
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- ID:
- ivo://CDS.VizieR/J/ApJS/152/251
- Title:
- Indo-US library of coude feed stellar spectra
- Short Name:
- J/ApJS/152/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained spectra for 1273 stars using the 0.9m coude feed telescope at Kitt Peak National Observatory. This telescope feeds the coude spectrograph of the 2.1m telescope. The spectra have been obtained with the No.5 camera of the coude spectrograph and a Loral 3Kx1K CCD. Two gratings have been used to provide spectral coverage from 3460 to 9464{AA}, at a resolution of ~1{AA} FWHM and at an original dispersion of 0.44{AA}/pix. For 885 stars we have complete spectra over the entire 3460 to 9464{AA} wavelength region (neglecting small gaps of less than 50{AA}), and partial spectral coverage for the remaining stars. The 1273 stars have been selected to provide broad coverage of the atmospheric parameters T_eff_, logg, and [Fe/H], as well as spectral type. The goal of the project is to provide a comprehensive library of stellar spectra for use in the automated classification of stellar and galaxy spectra and in galaxy population synthesis. In this paper we discuss the characteristics of the spectral library, viz., details of the observations, data reduction procedures, and selection of stars. We also present a few illustrations of the quality and information available in the spectra. The first version of the complete spectral library is now publicly available from the National Optical Astronomy Observatory (NOAO) via ftp and http, at http://www.noao.edu/cflib .
- ID:
- ivo://CDS.VizieR/J/MNRAS/461/2288
- Title:
- Infall motions in massive star-forming regions
- Short Name:
- J/MNRAS/461/2288
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we aim to characterize high-mass clumps with infall motions. We selected 327 clumps from the Millimetre Astronomy Legacy Team 90-GHz survey, and identified 100 infall candidates. Combined with the results of He et al. (2015, Cat. J/MNRAS/450/1926), we obtained a sample of 732 high-mass clumps, including 231 massive infall candidates and 501 clumps where infall is not detected. Objects in our sample were classified as pre-stellar, proto-stellar, HII or photodissociation region (PDR). The detection rates of the infall candidates in the pre-stellar, proto-stellar, HII and PDR stages are 41.2 per cent, 36.6 per cent, 30.6 per cent and 12.7 per cent, respectively. The infall candidates have a higher H_2_ column density and volume density compared with the clumps where infall is not detected at every stage. For the infall candidates, the median values of the infall rates at the pre-stellar, proto-stellar, HII and PDR stages are 2.6 x 10^-3^, 7.0x10^-3^, 6.5x10^-3^ and 5.5x10^-3^M_{sun}_/yr, respectively. These values indicate that infall candidates at later evolutionary stages are still accumulating material efficiently. It is interesting to find that both infall candidates and clumps where infall is not detected show a clear trend of increasing mass from the pre-stellar to proto-stellar, and to the HII stages. The power indices of the clump mass function are 2.04+/-0.16 and 2.17+/-0.31 for the infall candidates and clumps where infall is not detected, respectively, which agree well with the power index of the stellar initial mass function (2.35) and the cold Planck cores (2.0).
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/1926
- Title:
- Infall motions in massive star-forming regions
- Short Name:
- J/MNRAS/450/1926
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive star-forming regions with observed infall motions are good sites for studying the birth of massive stars. In this paper, 405 compact sources have been extracted from the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) compact sources that also have been observed in the Millimetre Astronomy Legacy Team 90-GHz (MALT90) survey during years 1 and 2. These observations are complemented with Spitzer GLIMPSE/MIPSGAL mid-IR survey data to help classify the elected star-forming clumps into three evolutionary stages: pre-stellar, proto-stellar and UCHII regions. The results suggest that 0.05g/cm^2^ is a reliable empirical lower bound for the clump surface densities required for massive-star formation to occur. The optically thick HCO^+^(1-0) and HNC(1-0) lines, as well as the optically thin N_2_H^+^(1-0) line were used to search for infall motions towards these sources. By analysing the asymmetries of the optically thick HCO^+^(1-0) and HNC(1-0) lines and the mapping observations of HCO^+^(1-0), a total of 131 reliable infall candidates have been identified. The HCO^+^(1-0) line shows the highest occurrence of obvious asymmetric features, suggesting that it may be a better infall motion tracer than other lines such as HNC(1-0). The detection rates of infall candidates towards pre-stellar, proto-stellar and UCHII clumps are 0.3452, 0.3861 and 0.2152, respectively. The relatively high detection rate of infall candidates towards UCHII clumps indicates that many UCHII regions are still accreting matter. The peak column densities and masses of the infall candidates, in general, display an increasing trend with progressing evolutionary stages. However, the rough estimates of the mass infall rate show no obvious variation with evolutionary stage.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/131
- Title:
- Infrared absorbance of water H_2_O/H_2_O_2_ ice
- Short Name:
- J/ApJ/743/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent surface chemistry experiments have shown that the hydrogenation of molecular oxygen on interstellar dust grains is a plausible formation mechanism, via hydrogen peroxide (H_2_O_2_), for the production of water (H_2_O) ice mantles in the dense interstellar medium. Theoretical chemistry models also predict the formation of a significant abundance of H_2_O_2_ ice in grain mantles by this route. At their upper limits, the predicted and experimental abundances are sufficiently high that H_2_O_2_ should be detectable in molecular cloud ice spectra. To investigate this further, laboratory spectra have been obtained for H_2_O_2_/H_2_O ice films between 2.5 and 200um, from 10 to 180K, containing 3%, 30%, and 97% H_2_O_2_ ice. Integrated absorbances for all the absorption features in low-temperature H_2_O_2_ ice have been derived from these spectra. For identifying H_2_O_2_ ice, the key results are the presence of unique features near 3.5, 7.0, and 11.3um. Comparing the laboratory spectra with the spectra of a group of 24 protostars and field stars, all of which have strong H_2_O ice absorption bands, no absorption features are found that can definitely be identified with H_2_O_2_ ice. In the absence of definite H_2_O_2_ features, the H_2_O_2_ abundance is constrained by its possible contribution to the weak absorption feature near 3.47um found on the long-wavelength wing of the 3um H_2_O ice band. This gives an average upper limit for H_2_O_2_, as a percentage of H_2_O, of 9%+/-4%. This is a strong constraint on parameters for surface chemistry experiments and dense cloud chemistry models.
- ID:
- ivo://CDS.VizieR/J/other/JAD/18.3
- Title:
- Infrared extinction spectra of aerosols
- Short Name:
- J/other/JAD/18.3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mid-infrared extinction spectra (500-6000cm^-1^) of a series of single-component aerosol particle ensembles representative of those found in a range of planetary and lunar atmospheres are presented. The aerosols were generated in the laboratory via condensation from the gas phase in a bath gas cooling cell, and the spectra recorded using a Fourier transform infrared spectrometer. This paper is the first in a series aimed towards building a spectral database for use in remote sensing of aerosols. The aerosol substances included here are methane, ethane, propane, butane, pentane, ethylene, acetylene, carbon dioxide, ammonia and sulfur dioxide.
- ID:
- ivo://CDS.VizieR/J/ApJ/737/73
- Title:
- Infrared extinction toward the Galactic Centre
- Short Name:
- J/ApJ/737/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the extinction curve toward the Galactic center (GC) from 1 to 19um. We use hydrogen emission lines of the minispiral observed by ISO-SWS and SINFONI. The extinction-free flux reference is the 2cm continuum emission observed by the Very Large Array. Toward the inner 14"x20", we find an extinction of A_2.166um_=2.62+/-0.11, with a power-law slope of {alpha}=-2.11+/-0.06 shortward of 2.8um, consistent with the average near-infrared slope from the recent literature. At longer wavelengths, however, we find that the extinction is grayer than shortward of 2.8um. We find that it is not possible to fit the observed extinction curve with a dust model consisting of pure carbonaceous and silicate grains only, and the addition of composite particles, including ices, is needed to explain the observations. Combining a distance-dependent extinction with our distance-independent extinction, we derive the distance to the GC to be R_0_=7.94+/-0.65kpc. Toward Sgr A* (r<0.5"), we obtain A_H_=4.21+/-0.10, A_Ks_=2.42+/-0.10, and A_L'_=1.09+/-0.13.
- ID:
- ivo://CDS.VizieR/J/ApJ/784/126
- Title:
- Infrared photometry of all known members in Taurus
- Short Name:
- J/ApJ/784/126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled photometry at 3.4, 4.6, 12, and 22{mu}m from the all-sky survey performed by the Wide-field Infrared Survey Explorer (WISE) for all known members of the Taurus complex of dark clouds. Using these data and photometry from the Spitzer Space Telescope, we have identified members with infrared excess emission from circumstellar disks and have estimated the evolutionary stages of the detected disks, which include 31 new full disks and 16 new candidate transitional, evolved, evolved transitional, and debris disks. We have also used the WISE All-Sky Source Catalog to search for new disk-bearing members of Taurus based on their red infrared colors. Through optical and near-infrared spectroscopy, we have confirmed 26 new members with spectral types of M1-M7. The census of disk-bearing stars in Taurus should now be largely complete for spectral types earlier than ~M8(M{>~}0.03M_{sun}_).
- ID:
- ivo://CDS.VizieR/J/A+A/372/245
- Title:
- Infrared properties of barium stars
- Short Name:
- J/A+A/372/245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a systematic survey for IRAS associations of barium stars. A total of 155 associations were detected, and IRAS low-resolution spectra exist for 50 barium stars. We use different color-color diagrams from the visual band to 60{mu}m, relations between these colors and the spectral type, the barium intensity, and the IRAS low-resolution spectra to discuss physical properties of barium stars in the infrared. It is confirmed that most barium stars have infrared excesses in the near infrared. However, a new result of this work is that most barium stars have no excesses in the far infrared. This fact may imply that infrared excesses of barium stars are mainly due to the re-emission of energy lost from the Bond-Neff depression. It is also shown that the spectral type and the barium intensity of barium stars are not correlated with infrared colors, but may be correlated with V-K color.
- ID:
- ivo://CDS.VizieR/J/A+A/505/L5
- Title:
- Infrared radial velocities of vB10
- Short Name:
- J/A+A/505/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocities of the M8V-type, very low-mass star vB 10 obtained at four different epochs between 2001 and 2008. We use high-resolution (R~20000) near-infrared (J-band) spectra taken with the NIRSPEC instrument on the Keck II telescope. Our data suggest that vB 10 shows radial velocity variability with an amplitude of ~1km/s, a result that is consistent with the recent finding of a massive planet companion around the star. More velocity measurements and a better sampling of the orbital phase are required to precisely constrain the orbital parameters and the individual masses of the pair.
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