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1231. IRAS 16293-2422 spectral cubes
ID:
ivo://CDS.VizieR/J/A+A/633/A7
Title:
IRAS 16293-2422 spectral cubes
Short Name:
J/A+A/633/A7
Date:
21 Oct 2021
Publisher:
CDS
Description:
Temperature is a crucial parameter in circumstellar disk evolution and planet formation because it governs the resistance of the gas to gravitational instability and sets the chemical composition of the planet-forming material. We set out to determine the gas temperature of the young disk-like structure around the Class 0 protostar IRAS 16293-2422A. We used Atacama Large Millimeter/submillimeter Array (ALMA) observations of multiple H_2_CS J=7-6 and J=10-9 lines from the Protostellar Interferometric Line Survey (PILS) to create a temperature map for the inner ~200AU of the disk-like structure. This molecule is a particularly useful temperature probe because transitions between energy levels with different K_a quantum numbers operate only through collisions. Based on the H_2_CS line ratios, the temperature is between ~100-175K in the inner ~150AU, and drops to ~75K at ~200AU. At the current resolution (0.5"~70AU), no jump is seen in the temperature at the disk-envelope interface. The temperature structure derived from H_2_CS is consistent with envelope temperature profiles that constrain the temperature from 1000AU scales down to ~100AU, but does not follow the temperature rise seen in these profiles at smaller radii. Higher angular resolution observations of optically thin temperature tracers are needed to establish whether cooling by gas-phase water, the presence of a putative disk, or the dust optical depth influences the gas temperature at <~100AU scales. The temperature at 100AU is higher in IRAS 16293A than in the embedded Class 0/I disk L1527, consistent with the higher luminosity of the former.
1232. IRAS 22023+5249 spectroscopy
ID:
ivo://CDS.VizieR/J/MNRAS/421/679
Title:
IRAS 22023+5249 spectroscopy
Short Name:
J/MNRAS/421/679
Date:
21 Oct 2021
Publisher:
CDS
Description:
The first high-resolution (R~50000) optical spectrum of the B-type star, LS III +52 24, identified as the optical counterpart of the hot post-asymptotic giant branch (post-AGB) candidate IRAS 22023+5249 (I22023) is presented. We report the detailed identifications of the observed absorption and emission features in the full wavelength range (4290-9015{AA}) as well as the atmospheric parameters and photospheric abundances (under the local thermodynamic equilibrium approximation) for the first time. The nebular parameters (Te, Ne) are also derived.
1233. IRAS 16293-2422 spectrum
ID:
ivo://CDS.VizieR/J/A+A/585/A112
Title:
IRAS 16293-2422 spectrum
Short Name:
J/A+A/585/A112
Date:
21 Oct 2021
Publisher:
CDS
Description:
A fraction of the missing sulfur in dense clouds and circumstellar regions could be in the form of three species not yet detected in the interstellar medium: H_2_S_2_, HS_2_, and S_2_ according to experimental simulations performed under astrophysically relevant conditions. These S-S bonded molecules can be formed by the energetic processing of H_2_S-bearing ice mantles on dust grains, and subsequently desorb to the gas phase. The detection of these species could partially solve the sulfur depletion problem, and would help to improve our knowledge of the poorly known chemistry of sulfur in the interstellar medium. To this purpose we calculated the frequencies and expected intensities of the rotational transitions not previously reported, and performed dedicated ground-based observations toward the low-mass warm core IRAS 16293-2422, a region with one of the highest measured gas-phase H_2_S abundances. Observations in the submillimeter regime were obtained with the APEX 12m telescope during 15h of observation. A total of ~16GHz were covered in a range of about 100GHz, targeting a wide selection of the predicted rotational transitions of the three molecules.
1234. IR band features around HD100546
ID:
ivo://CDS.VizieR/J/A+A/649/A84
Title:
IR band features around HD100546
Short Name:
J/A+A/649/A84
Date:
22 Feb 2022
Publisher:
CDS
Description:
Carbonaceous nanograins are present at the surface of protoplanetary disks around Herbig Ae/Be stars, where most of the ultraviolet energy from the central star is dissipated. Efficiently coupled to the gas, they are unavoidable to understand the physics and chemistry of these disks. Furthermore, nanograins are able to trace the outer flaring parts of the disk and possibly the gaps from which the larger grains are missing. However, their evolution through the disks, from internal to external regions, is only poorly understood so far. Our aim is to examine the spatial distribution and evolution of the nanodust emission in the emblematic (pre-)transitional protoplanetary disk HD 100546. This disk shows many structures (annular gaps, rings, and spirals) and reveals very rich carbon nanodust spectroscopic signatures (aromatic, aliphatic) in a wide spatial range of the disk (~20-200au). We analysed adaptive optics spectroscopic observations in the 3-4um range (angular resolution of ~0.1") and imaging and spectroscopic observations in the 8-12um range (angular resolution of ~0.3"). The hyperspectral cube was decomposed into a sum of spatially coherent dust components using a Gaussian decomposition algorithm. We compared the data to model predictions using the heterogeneous dust evolution model for interstellar solids (THEMIS), which is integrated in the radiative transfer code POLARIS by calculating the thermal and stochastic heating of micro- and nanometre-sized dust grains for a given disk structure. We find that the aromatic features at 3.3, 8.6, and 11.3um, and the aliphatic features between 3.4 and 3.5um are spatially extended; each band shows a specific morphology dependent on the local physical conditions. The aliphatic-to-aromatic band ratio, 3.4/3.3, increases with the distance from the star from ~0.2 (at 0.2" or 20au) to ~0.45 (at 1" or 100au), suggesting UV processing. In the 8-12um observed spectra, several features characteristic of aromatic particles and crystalline silicates are detected. Their relative contribution changes with the distance to the star. The model predicts that the features and adjacent continuum are due to different combinations of grain sub-populations, in most cases with a high dependence on the intensity of the UV field. The model reproduces the spatial emission profiles of the bands well, except for the inner 20-40au, where the observed emission of the 3.3 and 3.4um bands is, unlike the predictions, flat and no longer increases with the UV field. With our approach that combines observational data in the near- to mid-IR and disk modelling, we deliver constraints on the spatial distribution of nano-dust particles as a function of the disk structure and radiation field.
1235. IR-bright MSX sources in the SMC with Spitzer/IRS
ID:
ivo://CDS.VizieR/J/ApJ/834/185
Title:
IR-bright MSX sources in the SMC with Spitzer/IRS
Short Name:
J/ApJ/834/185
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have used the Infrared Spectrograph (IRS) on the Spitzer Space Telescope to observe stars in the Small Magellanic Cloud (SMC) selected from the Point Source Catalog of the Midcourse Space Experiment (MSX). We concentrate on the dust properties of the oxygen-rich evolved stars. The dust composition has smaller contributions from alumina compared to the Galaxy. This difference may arise from the lower metallicity in the SMC, but it could be a selection effect, as the SMC sample includes more stars that are brighter and thus more massive. The distribution of the SMC stars along the silicate sequence looks more like the Galactic sample of red supergiants than asymptotic giant branch stars (AGBs). While many of the SMC stars are definitively on the AGB, several also show evidence of hot bottom burning. Three of the supergiants show PAH emission at 11.3{mu}m. Two other sources show mixed chemistry, with both carbon-rich and oxygen-rich spectral features. One, MSX SMC 134, may be the first confirmed silicate/carbon star in the SMC. The other, MSX SMC 049, is a candidate post-AGB star. MSX SMC 145, previously considered a candidate OH/IR star, is actually an AGB star with a background galaxy at z=0.16 along the same line of sight. We consider the overall characteristics of all the MSX sources, the most infrared-bright objects in the SMC, in light of the higher sensitivity and resolution of Spitzer, and compare them with the object types expected from the original selection criteria. This population represents what will be seen in more distant galaxies by the upcoming James Webb Space Telescope (JWST). Color-color diagrams generated from the IRS spectra and the mid-infrared filters on JWST show how one can separate evolved stars from young stellar objects (YSOs) and distinguish among different classes of YSOs.
1236. IRC+10216 as a spectroscopic laboratory
ID:
ivo://CDS.VizieR/J/A+A/618/A4
Title:
IRC+10216 as a spectroscopic laboratory
Short Name:
J/A+A/618/A4
Date:
21 Oct 2021
Publisher:
CDS
Description:
This work presents a detailed analysis of the laboratory and astrophysical spectral data available for ^28^SiC_2_, ^29^SiC_2_, ^30^SiC_2_, Si^13^CC, and Si_2_C. New data on the rotational lines of these species between 70 and 350GHz have been obtained with high spectral resolution (195kHz) with the IRAM 30m telescope in the direction of the circumstellar envelope IRC+10216. Frequency measurements can reach an accuracy of 50kHz for features observed with a good signal to noise ratio. From the observed astrophysical lines and the available laboratory data new rotational and centrifugal distortion constants have been derived for all the isotopologues of SiC_2_, allowing to predict their spectrum with high accuracy in the millimeter and submillimeter domains. Improved rotational and centrifugal distortion constants have also been obtained for disilicon carbide, Si_2_C. This work shows that observations of IRC+10216 taken with the IRAM 30m telescope, with a spectral resolution of 195kHz, can be used for any molecular species detected in this source to derive, or improve, its rotational constants. Hence, IRC+10216 in addition to be one the richest sources in molecular species in the sky, can also be used as a state-of-the-art spectroscopy laboratory in the millimeter and submillimeter domains.
1237. IRC +10216 17.8GHz-26.3GHz spectrum
ID:
ivo://CDS.VizieR/J/A+A/574/A56
Title:
IRC +10216 17.8GHz-26.3GHz spectrum
Short Name:
J/A+A/574/A56
Date:
21 Oct 2021
Publisher:
CDS
Description:
IRC +10216 is the prototypical carbon star exhibiting an extended molecular circumstellar envelope. Its spectral properties are therefore the template for an entire class of objects. The main goal is to systematically study the 1.3cm spectral line characteristics of IRC +10216. We carried out a spectral line survey with the Effelsberg-100m telescope toward IRC +10216. It covers the frequency range between 17.8GHz and 26.3GHz (K-band). In the circumstellar shell of IRC +10216, we find 78 spectral lines, among which 12 remain unidentified. The identified lines are assigned to 18 different molecules and radicals. A total of 23 lines from species known to exist in this envelope are detected for the first time outside the Solar System and there are additional 20 lines firstly detected in IRC +10216. The potential orgin of U lines is also discussed. Assuming local thermodynamic equilibrium (LTE), we determine rotational temperatures and column densities of 17 detected molecules. Molecular abundances relative to H_2_ are also estimated. A non-LTE analysis of NH_3_ shows that the bulk of its emission arises from the inner envelope with a kinetic temperature of 70+/-20K. Evidence for NH_3_ emitting gas with higher kinetic temperature is also obtained, and potential abundance differences between various ^13^C-bearing isotopologues of HC_5_N are evaluated. Overall, the isotopic ^12^C/^13^C ratio is estimated to be 49+/-9. Finally, a comparison of detected molecules in the 1.3cm range with the dark cloud TMC-1 indicates that silicate bearing molecules are more predominant in IRC +10216.
1238. IRC +10216 13.3GHz-18.5GHz spectrum
ID:
ivo://CDS.VizieR/J/A+A/606/A74
Title:
IRC +10216 13.3GHz-18.5GHz spectrum
Short Name:
J/A+A/606/A74
Date:
21 Oct 2021
Publisher:
CDS
Description:
A spectral line survey of IRC +10216 between 13.3 and 18.5GHz was carried out using the Shanghai Tian Ma 65 m Radio Telescope (TMRT-65m) with a sensitivity of <7mK. Thirty-five spectral lines of 12 different molecules and radicals were detected in total. Except for SiS, the detected molecules are all carbon-chain molecules, including HC_3_N, HC_5_N, HC_7_N, HC_9_N, C_6_H, C_6_H^-^, C_8_H, SiC_2_, SiC_4_, c-C_3_H_2_, and l-C_5_H. The presence of rich carbon-bearing molecules is consistent with the identity of IRC +10216 as a carbon-rich asymptotic giant branch (AGB) star. The excitation temperatures and column densities of the observed species are derived by assuming a local thermodynamic equilibrium and homogeneous conditions.
1239. IR continuum, [CII] and [OI] maps of M33
ID:
ivo://CDS.VizieR/J/A+A/639/A61
Title:
IR continuum, [CII] and [OI] maps of M33
Short Name:
J/A+A/639/A61
Date:
21 Oct 2021
Publisher:
CDS
Description:
M33 is a gas rich spiral galaxy of the Local Group. Its vicinity allows us to study its interstellar medium (ISM) on linear scales corresponding to the sizes of individual giant molecular clouds. We investigate the relationship between the two major gas cooling lines and the total infrared (TIR) dust continuum. We mapped the emission of gas and dust in M33 using the far-infrared lines of [CII] and [OI](63um) and the total infrared continuum. The line maps were observed with the PACS spectrometer on board the Herschel Space Observatory. These maps have 50pc resolution and form a ~370pc wide stripe along its major axis covering the sites of bright HII regions, but also more quiescent arm and inter-arm regions from the southern arm at 2kpc galacto-centric distance to the south out to 5.7kpc distance to the north. Full-galaxy maps of the continuum emission at 24um from Spitzer/MIPS, and at 70um, 100um, and 160um from Herschel/PACS were combined to obtain a map of the TIR. TIR and [CII] intensities are correlated over more than two orders of magnitude. The range of TIR translates to a range of far ultraviolet (FUV) emission of G_0,obs_~2 to 200 in units of the average Galactic radiation field. The binned [CII]/TIR ratio drops with rising TIR, with large, but decreasing scatter. The contribution of the cold neutral medium to the [CII] emission, as estimated from VLA HI data, is on average only 10%. Fits of modified black bodies (MBBs) to the continuum emission were used to estimate dust mass surface densities and total gas column densities. A correction for possible foreground absorption by cold gas was applied to the [OI] data before comparing it with models of photon dominated regions (PDRs). Most of the ratios of [CII]/[OI] and ([CII]+[OI])/TIR are consistent with two model solutions. The median ratios are consistent with one solution at n~2x10^2^cm^-3^, G_0_~60, and and a second low-FUV solution at n~10^4^cm^-3^, G_0_~1.5. The bulk of the gas along the lines-of-sight is represented by a low-density, high-FUV phase with low beam filling factors ~1. A fraction of the gas may, however, be represented by the second solution.
1240. IRD and HPF spectra of TRAPPIST-1b,e and f
ID:
ivo://CDS.VizieR/J/AJ/162/82
Title:
IRD and HPF spectra of TRAPPIST-1b,e and f
Short Name:
J/AJ/162/82
Date:
11 Mar 2022
Publisher:
CDS
Description:
We obtained high-resolution spectra of the ultracool M-dwarf TRAPPIST-1 during the transit of its planet "b" using two high-dispersion near-infrared spectrographs, the Infrared Doppler (IRD) instrument on the Subaru 8.2m telescope, and the Habitable Zone Planet Finder (HPF) instrument on the 10m Hobby-Eberly Telescope. These spectroscopic observations are complemented by a photometric transit observation for planet "b" using the APO/ARCTIC, which assisted us in capturing the correct transit times for our transit spectroscopy. Using the data obtained by the new IRD and HPF observations, as well as the prior transit observations of planets "b," "e" and "f" from IRD, we attempt to constrain the atmospheric escape of the planet using the Hei triplet 10830{AA} absorption line. We do not detect evidence for any primordial extended H-He atmospheres in all three planets. To limit any planet-related absorption, we place an upper limit on the equivalent widths of <7.754m{AA} for planet "b," <10.458m{AA} for planet "e," <4.143m{AA} for planet "f" at 95% confidence from the IRD data, and <3.467m{AA} for planet "b" at 95% confidence from HPF data. Using these limits along with a solar- like composition isothermal Parker wind model, we attempt to constrain the mass-loss rates for the three planets. For TRAPPIST-1b, our models exclude the highest possible energy-limited rate for a wind temperature <5000K. This nondetection of extended atmospheres with low mean-molecular weights in all three planets aids in further constraining their atmospheric composition by steering the focus toward the search of high-molecular-weight species in their atmospheres.

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