Mapping CO Gas in the GG Tauri A Triple System with 50 AU Spatial Resolution

We aim to unveil the observational imprint of physical mechanisms that govern planetary formation in the young, multiple system GG Tau A. We present ALMA observations of $^{12}$CO and $^{13}$CO 3-2 and 0.9 mm continuum emission with 0.35" resolution. The $^{12}$CO 3-2 emission, found within the cavity of the circumternary dust ring (at radius $< 180$ AU) where no $^{13}$CO emission is detected, confirms the presence of CO gas near the circumstellar disk of GG Tau Aa. The outer disk and the recently detected hot spot lying at the outer edge of the dust ring are mapped both in $^{12}$CO and $^{13}$CO. The gas emission in the outer disk can be radially decomposed as a series of slightly overlapping Gaussian rings, suggesting the presence of unresolved gaps or dips. The dip closest to the disk center lies at a radius very close to the hot spot location at $\sim250-260$~AU. The CO excitation conditions indicate that the outer disk remains in the shadow of the ring. The hot spot probably results from local heating processes. The two latter points reinforce the hypothesis that the hot spot is created by an embedded proto-planet shepherding the outer disk.Comment: 8 pages, 4 figures. Accepted by Ap

Revised spectroscopic parameters of SH from ALMA and IRAM 30 m observations

International audienceHydrides represent the first steps of interstellar chemistry. Sulfanylium (SH ), in particular, is a key tracer of energetic processes. We used ALMA and the IRAM 30 m telescope to search for the lowest frequency rotational lines of SH toward the Orion Bar, the prototypical photo-dissociation region illuminated by a strong UV radiation field. On the basis of previous Herschel/HIFI observations of SH , we expected to detect emission of the two SH hyperfine structure (HFS) components of the NJ = 10-01 fine structure (FS) component near 346 GHz. While we did not observe any lines at the frequencies predicted from laboratory data, we detected two emission lines, each ~15 MHz above the SH predictions and with relative intensities and HFS splitting expected for SH . The rest frequencies of the two newly detected lines are more compatible with the remainder of the SH laboratory data than the single line measured in the laboratory near 346 GHz and previously attributed to SH . Therefore, we assign these new features to the two SH HFS components of the NJ = 10-01 FS component and re-determine its spectroscopic parameters, which will be useful for future observations of SH , in particular if its lowest frequency FS components are studied. Our observations demonstrate the suitability of these lines for SH searches at frequencies easily accessible from the ground

SL9 Species Imaging in Jupiter's Auroral Regions with ALMA

International audienceComet Shoemaker-Levy 9 (SL9) impacted Jupiter in 1994 at mid-southern latitudes. The impacts resulted in the delivery of new species to Jupiter's stratosphere, like CO, HCN, CS, H2O and CO2. These species have been used ever since to assess stratospheric chemistry and the magnitude of meridional transport. In March 2017, and thus more than 20 years after the impacts, we successfully mapped HCN and CO with ALMA. Our observations provide us with a latitudinal resolution of 3\,^{\circ} at the equator and 7\,^{\circ} at 70\,^{\circ}S. While most of the material is confined to the mbar level from the low to the mid latitudes, in agreement with predictions, we find unexpected emissions at high altitudes in the south polar region. These emissions are very well correlated with the position of the auroral oval. At the observation central meridian longitude, the northern auroral oval was not very visible from Earth, regardless of any SL9-related hemispheric differences in HCN and CO abundances. We will present our observations and discuss the implications on stratospheric chemistry, temperature and advective transport

SL9 Species Imaging in Jupiter's Auroral Regions with ALMA

International audienceComet Shoemaker-Levy 9 (SL9) impacted Jupiter in 1994 at mid-southern latitudes. The impacts resulted in the delivery of new species to Jupiter's stratosphere, like CO, HCN, CS, H2O and CO2. These species have been used ever since to assess stratospheric chemistry and the magnitude of meridional transport. In March 2017, and thus more than 20 years after the impacts, we successfully mapped HCN and CO with ALMA. Our observations provide us with a latitudinal resolution of 3\,^{\circ} at the equator and 7\,^{\circ} at 70\,^{\circ}S. While most of the material is confined to the mbar level from the low to the mid latitudes, in agreement with predictions, we find unexpected emissions at high altitudes in the south polar region. These emissions are very well correlated with the position of the auroral oval. At the observation central meridian longitude, the northern auroral oval was not very visible from Earth, regardless of any SL9-related hemispheric differences in HCN and CO abundances. We will present our observations and discuss the implications on stratospheric chemistry, temperature and advective transport

SL9 Species Imaging in Jupiter's Auroral Regions with ALMA

International audienceComet Shoemaker-Levy 9 (SL9) impacted Jupiter in 1994 at mid-southern latitudes. The impacts resulted in the delivery of new species to Jupiter's stratosphere, like CO, HCN, CS, H2O and CO2. These species have been used ever since to assess stratospheric chemistry and the magnitude of meridional transport. In March 2017, and thus more than 20 years after the impacts, we successfully mapped HCN and CO with ALMA. Our observations provide us with a latitudinal resolution of 3\,^{\circ} at the equator and 7\,^{\circ} at 70\,^{\circ}S. While most of the material is confined to the mbar level from the low to the mid latitudes, in agreement with predictions, we find unexpected emissions at high altitudes in the south polar region. These emissions are very well correlated with the position of the auroral oval. At the observation central meridian longitude, the northern auroral oval was not very visible from Earth, regardless of any SL9-related hemispheric differences in HCN and CO abundances. We will present our observations and discuss the implications on stratospheric chemistry, temperature and advective transport

Revised spectroscopic parameters of SH+^+ from ALMA and IRAM 30 m observations

Hydrides represent the first steps of interstellar chemistry. Sulfanylium (SH$^+$), in particular, is a key tracer of energetic processes. We used ALMA and the IRAM 30 m telescope to search for the lowest frequency rotational lines of SH$^+$ toward the Orion Bar, the prototypical photo-dissociation region illuminated by a strong UV radiation field. On the basis of previous $Herschel$/HIFI observations of SH$^+$, we expected to detect emission of the two SH$^+$ hyperfine structure (HFS) components of the $N_J = 1_0 - 0_1$ fine structure (FS) component near 346 GHz. While we did not observe any lines at the frequencies predicted from laboratory data, we detected two emission lines, each $\sim$15 MHz above the SH$^+$ predictions and with relative intensities and HFS splitting expected for SH$^+$. The rest frequencies of the two newly detected lines are more compatible with the remainder of the SH$^+$ laboratory data than the single line measured in the laboratory near 346 GHz and previously attributed to SH$^+$. Therefore, we assign these new features to the two SH$^+$ HFS components of the $N_J = 1_0 - 0_1$ FS component and re-determine its spectroscopic parameters, which will be useful for future observations of SH$^+$, in particular if its lowest frequency FS components are studied. Our observations demonstrate the suitability of these lines for SH$^+$ searches at frequencies easily accessible from the ground

PRODIGE – planet-forming disks in Taurus with NOEMA: Overview and first results for 12^{12}CO, 13^{13}CO, and C18^{18}O

International audienceContext: The physics and chemistry of planet-forming disks are far from being fully understood. To make further progress, both broad line surveys and observations of individual tracers in a statistically significant number of disks are required.Aims: Our aim is to perform a line survey of eight planet-forming Class II disks in Taurus with the IRAM NOrthern Extended Millimeter Array (NOEMA), as a part of the MPG-IRAM Observatory Program PRODIGE (PROtostars and DIsks: Global Evolution; PIs: P. Caselli and Th. Henning).Methods: Compact and extended disks around T Tauri stars CI, CY, DG, DL, DM, DN, IQ Tau, and UZ Tau E are observed in ~80 lines from &gt; 20 C-, O,- N-, and S-bearing species. The observations in four spectral settings at 210–280 GHz with a 1σ rms sensitivity of ~8–12 mJy beam −1 at a 0.9″ and 0.3 km s$^{−1}$ resolution will be completed in 2024. The uv visibilities are fitted with the DiskFit model to obtain key stellar and disk properties.Results: In this first paper, the combined $^{12}$CO, $^{13}$CO, and C$^{18}$O J = 2–1 data are presented. We find that the CO fluxes and disk masses inferred from dust continuum tentatively correlate with the CO emission sizes. We constrained dynamical stellar masses, geometries, temperatures, the CO column densities, and gas masses for each disk. The best-fit temperatures at 100 au are ~ 17–37 K, and decrease radially with the power-law exponent q ~ 0.05–0.76. The inferred CO column densities decrease radially with the power-law exponent p ~ 0.2–3.1. The gas masses estimated from $^{13}$CO (2–1) are ~0.001–0.2 M ⊙ .Conclusions: Using NOEMA, we confirm the presence of temperature gradients in our disk sample. The best-fit CO column densities point to severe CO freeze-out in these disks. The DL Tau disk is an outlier, and has either stronger CO depletion or lower gas mass than the rest of the sample. The CO isotopologue ratios are roughly consistent with the observed values in disks and the low-mass star-forming regions. The high $^{13}$CO/C$^{18}$O ratio of ~23 in DM Tau could be indicative of strong selective photodissociation of C$^{18}$O in this disk