In recent years, exciting developments have taken place in the identification of the role of cosmic rays in star-forming environments. Observations from radio to infrared wavelengths and theoretical ...modelling have shown that low-energy cosmic rays (
<
1
TeV
) play a fundamental role in shaping the chemical richness of the interstellar medium, determining the dynamical evolution of molecular clouds. In this review we summarise in a coherent picture the main results obtained by observations and by theoretical models of propagation and generation of cosmic rays, from the smallest scales of protostars and circumstellar discs, to young stellar clusters, up to Galactic and extragalactic scales. We also discuss the new fields that will be explored in the near future thanks to new generation instruments, such as: CTA, for the
γ
-ray emission from high-mass protostars; SKA and precursors, for the synchrotron emission at different scales; and ELT/HIRES, JWST, and ARIEL, for the impact of cosmic rays on exoplanetary atmospheres and habitability.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
SY Cha is a T Tauri star surrounded by a protoplanetary disk with a large cavity seen in the millimeter continuum but has the spectral energy distribution of a full disk. Here we report the ...first results from JWST/Mid-InfraRed Instrument (MIRI) Medium Resolution Spectrometer (MRS) observations taken as part of the MIRI mid-INfrared Disk Survey (MINDS) GTO Program. The much improved resolution and sensitivity of MIRI-MRS compared to Spitzer enables a robust analysis of the previously detected H
2
O, CO, HCN, and CO
2
emission as well as a marginal detection of C
2
H
2
. We also report the first robust detection of mid-infrared OH and rovibrational CO emission in this source. The derived molecular column densities reveal the inner disk of SY Cha to be rich in both oxygen- and carbon-bearing molecules. This is in contrast to PDS 70, another protoplanetary disk with a large cavity observed with JWST, which displays much weaker line emission. In the SY Cha disk, the continuum, and potentially the line, flux varies substantially between the new JWST observations and archival Spitzer observations, indicative of a highly dynamic inner disk.
We present JWST-MIRI Medium Resolution Spectrometer (MRS) spectra of the protoplanetary disk around the low-mass T Tauri star GW Lup from the MIRI mid-INfrared Disk Survey Guaranteed Time ...Observations program. Emission from 12CO2, 13CO2, H2O, HCN, C2H2, and OH is identified with 13CO2 being detected for the first time in a protoplanetary disk. We characterize the chemical and physical conditions in the inner few astronomical units of the GW Lup disk using these molecules as probes. The spectral resolution of JWST-MIRI MRS paired with high signal-to-noise data is essential to identify these species and determine their column densities and temperatures. The Q branches of these molecules, including those of hot bands, are particularly sensitive to temperature and column density. We find that the 12CO2 emission in the GW Lup disk is coming from optically thick emission at a temperature of ∼400 K. 13CO2 is optically thinner and based on a lower temperature of ∼325 K, and thus may be tracing deeper into the disk and/or a larger emitting radius than 12CO2. The derived NCO2/NH2O ratio is orders of magnitude higher than previously derived for GW Lup and other targets based on Spitzer-InfraRed-Spectrograph data. This high column density ratio may be due to an inner cavity with a radius in between the H2O and CO2 snowlines and/or an overall lower disk temperature. This paper demonstrates the unique ability of JWST to probe inner disk structures and chemistry through weak, previously unseen molecular features.
Galactic 26Al traces metal loss through hot chimneys Krause, Martin G H; Rodgers-Lee, Donna; Dale, James E ...
Monthly notices of the Royal Astronomical Society,
12/2020, Volume:
501, Issue:
1
Journal Article
Peer reviewed
Open access
ABSTRACT
Radioactive 26Al is an excellent tracer for metal ejection in the Milky Way, and can provide a direct constraint on the modelling of supernova feedback in galaxy evolution. Gamma-ray ...observations of the 26Al decay line have found high velocities and hence require a significant fraction of the Galactic 26Al in the hot component. At the same time, meteoritic data combined with simulation results suggest that a significant amount of 26Al makes its way into stars before decay. We investigated the distribution into hot and cold channels with a simulation of a Milky-Way-like galaxy with massive-star feedback in superbubbles and with ejecta traced by 26Al. About 30–40 per cent of the ejecta remain hot, with typical cooling times of the order Gyr. 26Al traces the footpoints of a chimney-fed outflow that mixes metals turbulently into the halo of the model galaxy on a scale of at least 50 kpc. The rest diffuses into cold gas ≲ 104 K, and may therefore be quickly available for star formation. We discuss the robustness of the result by comparison to a simulation with a different global flow pattern. The branching ratio into hot and cold components is comparable to that of longer term average results from chemical evolution modelling of galaxies, clusters, and the intracluster medium.
We present the results of a multiwavelength study of circumstellar discs around 44 young stellar objects in the 3 myr old nearby Chamaeleon-I star-forming region. In particular, we explore the ...far-infrared/submm regime using Herschel fluxes. We show that Herschel fluxes at 160–500 μm can be used to derive robust estimates of the disc mass. The median disc mass is 0.005 M⊙ for a sample of 28 Class IIs and 0.006 M⊙ for 6 transition discs (TDs). The fraction of objects in Chamaeleon-I with at least the ‘minimum mass solar nebula’ is 2–7 per cent. This is consistent with previously published results for Taurus, IC348 and ρ Oph. Diagrams of spectral slopes show the effect of specific evolutionary processes in circumstellar discs. Class II objects show a wide scatter that can be explained by dust settling. We identify a continuous trend from Class II to TDs. Including Herschel fluxes in this type of analysis highlights the diversity of TDs. We find that TDs are not significantly different from Class II discs in terms of far-infrared luminosity, disc mass or degree of dust settling. This indicates that inner dust clearing occurs independently from other evolutionary processes in the discs.
Context . Understanding the physical conditions of circumstellar material around young stars is crucial to star and planet formation studies. In particular, very low-mass stars ( M ★ < 0.2 M ⊙ ) are ...interesting sources to characterize as they are known to host a diverse population of rocky planets. Molecular and atomic hydrogen lines can probe the properties of the circumstellar gas. Aims . This work aims to measure the mass accretion rate, the accretion luminosity, and more generally the physical conditions of the warm emitting gas in the inner disk of the very low-mass star 2MASS-J16053215-1933159. We investigate the source mid-infrared spectrum for atomic and molecular hydrogen line emission. Methods . We present the full James Webb Space Telescope (JWST) Mid-InfraRed Instrument (MIRI) Medium Resolution Spectrometer (MRS) spectrum of the protoplanetary disk around the very low-mass star 2MASS-J16053215-1933159 from the MINDS GTO program, previously shown to be abundant in hydrocarbon molecules. We analyzed the atomic and molecular hydrogen lines in this source by fitting one or multiple Gaussian profiles. We then built a rotational diagram for the H 2 lines to constrain the rotational temperature and column density of the gas. Finally, we compared the observed atomic line fluxes to predictions from two standard emission models. Results . We identify five molecular hydrogen pure rotational lines and 16 atomic hydrogen recombination lines in the 5–20 µm spectral range. The spectrum indicates optically thin emission for both species. We use the molecular hydrogen lines to constrain the mass and temperature of the warm emitting gas. We derive a total gas mass of only 2.3 × 10 −5 M Jup and a temperature of 635 K for the warm H 2 gas component located in the very inner disk ( r < 0.033 au), which only accounts for a small fraction of the upper limit for the disk mass from continuum observations (0.2 M Jup ). The HI (7−6) recombination line is used to measure the mass accretion rate (4.0 × 10 −10 M ⊙ yr −1 ) and luminosity (3.1 × 10 −3 L ⊙ ) onto the central source. This line falls close to the HI (11−8) line, however at the spectral resolution of JWST MIRI we managed to measure both separately. Previous studies based on Spitzer have measured the combined flux of both lines to measure accretion rates. HI recombination lines can also be used to derive the physical properties of the gas using atomic recombination models. The model predictions of the atomic line relative intensities constrain the atomic hydrogen density to about 10 9 −10 10 cm −3 and temperatures up to 5000 K. Conclusions . The JWST-MIRI MRS observations for the very low-mass star 2MASS-J16053215-1933159 reveal a large number of emission lines, many originating from atomic and molecular hydrogen because we are able to look into the disk warm molecular layer. Their analysis constrains the physical properties of the emitting gas and showcases the potential of JWST to deepen our understanding of the physical and chemical structure of protoplanetary disks.
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9.
MINDS: The DR Tau disk Temmink, Milou; van Dishoeck, Ewine F.; Grant, Sierra L. ...
Astronomy and astrophysics (Berlin),
6/2024, Volume:
686
Journal Article
Peer reviewed
Open access
Context . The MRS mode of the JWST-MIRI instrument has been shown to be a powerful tool to characterise the molecular gas emission of the inner region of planet-forming disks. Investigating their ...spectra allows us to infer the composition of the gas in these regions and, subsequently, the potential atmospheric composition of the forming planets. We present the JWST-MIRI observations of the compact T-Tauri disk, DR Tau, which are complemented by ground-based, high spectral resolution ( R ~ 60 000–90 000) CO ro-vibrational observations. Aims . The aim of this work is to investigate the power of extending the JWST-MIRI CO observations with complementary, high-resolution, ground-based observations acquired through the SpExoDisks database, as JWST-MIRI’s spectral resolution ( R ~ 1500– 3500) is not sufficient to resolve complex CO line profiles. In addition, we aim to infer the excitation conditions of other molecular features present in the JWST-MIRI spectrum of DR Tau and link those with CO. Methods . The archival complementary, high-resolution CO ro-vibrational observations were analysed with rotational diagrams. We extended these diagrams to the JWST-MIRI observations by binning and convolution with JWST-MIRI’s pseudo-Voigt line profile. In parallel, local thermal equilibrium (LTE) 0D slab models were used to infer the excitation conditions of the detected molecular species. Results . Various molecular species, including CO, CO 2 , HCN, and C 2 H 2 , are detected in the JWST-MIRI spectrum of DR Tau, with H 2 O being discussed in a subsequent paper. The high-resolution observations show evidence for two 12 CO components: a broad component (full width at half maximum of FWHM ~33.5 km s −1 ) tracing the Keplerian disk and a narrow component ( FWHM ~ 11.6 km s −1 ) tracing a slow disk wind. The rotational diagrams yield CO excitation temperatures of T ≥ 725 K. Consistently lower excitation temperatures are found for the narrow component, suggesting that the slow disk wind is launched from a larger radial distance. In contrast to the ground-based observations, much higher excitation temperatures are found if only the high- J transitions probed by JWST-MIRI are considered in the rotational diagrams. Additional analysis of the 12 CO line wings suggests a larger emitting area than inferred from the slab models, hinting at a misalignment between the inner ( i ~ 20°) and the outer disk ( i ~ 5°). Compared to CO, we retrieved lower excitation temperatures of T ~ 325-900 K for 12 CO 2 , HCN, and C 2 H 2 . Conclusions . We show that complementary, high-resolution CO ro-vibrational observations are necessary to properly investigate the excitation conditions of the gas in the inner disk and they are required to interpret the spectrally unresolved JWST-MIRI CO observations. These additional observations, covering the lower- J transitions, are needed to put better constraints on the gas physical conditions and they allow for a proper treatment of the complex line profiles. A comparison with JWST-MIRI requires the use of pseudo-Voigt line profiles in the convolution rather than simple binning. The combined high-resolution CO and JWST-MIRI observations can then be used to characterise the emission, in addition to the physical and chemical conditions of the other molecules with respect to CO. The inferred excitation temperatures suggest that CO originates from the highest atmospheric layers close to the host star, followed by HCN and C 2 H 2 which emit, together with 13 CO, from slightly deeper layers, whereas the CO 2 emission originates from even deeper inside or further out of the disk.
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10.
MINDS: The DR Tau disk Temmink, Milou; van Dishoeck, Ewine F; Grant, Sierra L ...
Astronomy and astrophysics (Berlin),
06/2024, Volume:
686
Journal Article
Peer reviewed
Context. The MRS mode of the JWST-MIRI instrument has been shown to be a powerful tool to characterise the molecular gas emission of the inner region of planet-forming disks. Investigating their ...spectra allows us to infer the composition of the gas in these regions and, subsequently, the potential atmospheric composition of the forming planets. We present the JWST-MIRI observations of the compact T-Tauri disk, DR Tau, which are complemented by ground-based, high spectral resolution (R ~ 60 000–90 000) CO ro-vibrational observations. Aims. The aim of this work is to investigate the power of extending the JWST-MIRI CO observations with complementary, high-resolution, ground-based observations acquired through the SpExoDisks database, as JWST-MIRI’s spectral resolution (R ~ 1500– 3500) is not sufficient to resolve complex CO line profiles. In addition, we aim to infer the excitation conditions of other molecular features present in the JWST-MIRI spectrum of DR Tau and link those with CO. Methods. The archival complementary, high-resolution CO ro-vibrational observations were analysed with rotational diagrams. We extended these diagrams to the JWST-MIRI observations by binning and convolution with JWST-MIRI’s pseudo-Voigt line profile. In parallel, local thermal equilibrium (LTE) 0D slab models were used to infer the excitation conditions of the detected molecular species. Results. Various molecular species, including CO, CO2, HCN, and C2H2, are detected in the JWST-MIRI spectrum of DR Tau, with H2O being discussed in a subsequent paper. The high-resolution observations show evidence for two 12CO components: a broad component (full width at half maximum of FWHM ~33.5 km s−1) tracing the Keplerian disk and a narrow component (FWHM ~ 11.6 km s−1) tracing a slow disk wind. The rotational diagrams yield CO excitation temperatures of T ≥ 725 K. Consistently lower excitation temperatures are found for the narrow component, suggesting that the slow disk wind is launched from a larger radial distance. In contrast to the ground-based observations, much higher excitation temperatures are found if only the high-J transitions probed by JWST-MIRI are considered in the rotational diagrams. Additional analysis of the 12CO line wings suggests a larger emitting area than inferred from the slab models, hinting at a misalignment between the inner (i ~ 20°) and the outer disk (i ~ 5°). Compared to CO, we retrieved lower excitation temperatures of T ~ 325-900 K for 12CO2, HCN, and C2H2. Conclusions. We show that complementary, high-resolution CO ro-vibrational observations are necessary to properly investigate the excitation conditions of the gas in the inner disk and they are required to interpret the spectrally unresolved JWST-MIRI CO observations. These additional observations, covering the lower-J transitions, are needed to put better constraints on the gas physical conditions and they allow for a proper treatment of the complex line profiles. A comparison with JWST-MIRI requires the use of pseudo-Voigt line profiles in the convolution rather than simple binning. The combined high-resolution CO and JWST-MIRI observations can then be used to characterise the emission, in addition to the physical and chemical conditions of the other molecules with respect to CO. The inferred excitation temperatures suggest that CO originates from the highest atmospheric layers close to the host star, followed by HCN and C2H2 which emit, together with 13CO, from slightly deeper layers, whereas the CO2 emission originates from even deeper inside or further out of the disk.
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