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1. The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). III. Dust and Gas Disk Properties in the Lupus Star-forming Region

   https://doi.org/10.3847/1538-4357/add43a  

   Deng, Dingshan; Vioque, Miguel; Pascucci, Ilaria; Pérez, Laura M; Zhang, Ke; Kurtovic, Nicolás; Trapman, Leon; TorresVillanueva, Estephani E; Agurto-Gangas, Carolina; Carpenter, John; et al (July 2025, The Astrophysical Journal)

   Abstract We present Band 6 and Band 7 observations of 10 Lupus disks around M3-K6 stars from the Atacama Large Millimeter/submillimeter Array survey of Gas Evolution in PROtoplanetary disks (AGE-PRO) Large Program. In addition to continuum emission in both bands, our Band 6 setup covers the¹²CO,¹³CO, and C¹⁸OJ= 2–1 lines, while our Band 7 setup covers the N₂H⁺J= 3–2 line. All of our sources are detected in¹²CO and¹³CO; seven out of ten are detected in C¹⁸O; and three are detected in N₂H⁺. We find strong correlations between the CO isotopologue line fluxes and the continuum flux densities. With the exception of one disk, we also identify a strong correlation between the C¹⁸OJ= 2–1 and N₂H⁺J= 3–2 fluxes, indicating similar CO abundances across this sample. For the two sources with well-resolved continuum and¹²COJ= 2–1 images, we find that their gas-to-dust size ratio is consistent with the median value of ∼2 inferred from a larger sample of Lupus disks. We derive dust disk masses from continuum flux densities. We estimate gas disk masses by comparing C¹⁸OJ= 2–1 line fluxes with those predicted by the limited grid of self-consistent disk models of M. Ruaud et al. A comparison of these mass estimates with those derived by L. Trapman et al., using a combination of CO isotopologue and N₂H⁺line emission, shows that the masses are consistent with each other. Some discrepancies appear for small and faint disks, but they are still within the uncertainties. Both methods find gas disk masses increase with dust disk masses, and gas-to-dust mass ratios are between 10 and 100 in the AGE-PRO Lupus sample. 

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2. Expanding the Inventory of Molecule-rich Planetary Nebulae: New Observations of M4-17, Hu 1-1, M1-59, and Na 2

   https://doi.org/10.3847/1538-4357/ad83be  

   Gold, K R; Schmidt, D R; Ziurys, L M (November 2024, The Astrophysical Journal)

   Abstract Molecular observations of four planetary nebulae (PNe), M4-17, Hu 1-1, M1-59, and Na 2, were conducted at 1–3 mm using the Arizona Radio Observatory’s 12 m antenna and Submillimeter Telescope, and the Institut de Radioastronomie Millimétrique 30 m Telescope. Toward M4-17, HNC (J= 3 → 2), CCH (N= 2 → 1,N= 3 → 2), CN (N= 1 → 0,N= 2 → 1), H₂CO (J_Ka,Kc= 2_1,2→ 1_1,1,J_Ka,Kc= 2_0,2→ 1_0,1,J_Ka,Kc= 2_1,1→ 1_1,0), CS (J= 3 → 2,J= 5 → 4), and H¹³CN (J= 2 → 1) were detected. An almost identical set of transitions was identified toward Hu 1-1. Moreover, c–C₃H₂was detected in Hu 1-1 via three 2 mm lines:J_Ka,Kc= 3_1,2→ 2_2,1,J_Ka,Kc= 4_1,4→ 3_0,3, andJ_Ka,Kc= 3_{2, 2}→ 2_1,1. HNC, CCH, CN, CS, and H¹³CN were found in M1-59, as well as H₂S via itsJ_Ka,Kc= 1_1,0→ 1_0,1line—the first detection of this key sulfur species in PNe. In addition, CCH and CN were identified in the 27,000 yr old Na 2. Among these four sources, CN and CCH were the most prevalent molecules (after CO and H₂) with fractional abundances, relative to H₂, off∼ 0.9–7.5 × 10⁻⁷and 0.8–7.5 × 10⁻⁷, respectively. CS and HNC have abundances in the rangef∼ 0.5–5 × 10⁻⁸, the latter resulting in HCN/HNC ∼ 3 across all three PNe. The unusual species H₂CO, c–C₃H₂, and H₂S hadf∼ 3–4 × 10⁻⁷, 10⁻⁸, and 6 × 10⁻⁸. This study suggests that elliptical PNe such as Hu 1-1 can have a diverse molecular composition. The presence of CN, CCH, and HCO⁺in Na 2, with comparable abundances to younger PNe, demonstrates that molecular content is maintained into the late PN stage. 

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3. Physical and Chemical Properties of Galactic Molecular Gas toward QSO J1851+0035

   https://doi.org/10.3847/1538-4357/ad3d5b  

   Narita, Kanako; Sakamoto, Seiichi; Koda, Jin; Yoshimura, Yuki; Kohno, Kotaro (July 2024, The Astrophysical Journal)

   Abstract Atacama Large Millimeter/submillimeter Array (ALMA) data toward QSO J1851+0035 (l= 33.°498,b= +0.°194) were used to study absorption lines by Galactic molecular gas. We detected 17 species (CO,¹³CO, C¹⁸O, HCO⁺, H¹³CO⁺, HCO, H₂CO, C₂H,c-C₃H,c-C₃H₂, CN, HCN, HNC, CS, SO, SiO, and C) and set upper limits to 18 species as reference values for chemical models. About 20 independent velocity components at 4.7–10.9 kpc from the Galactic center were identified. Their column density and excitation temperature estimated from the absorption study, as well as the CO intensity distributions obtained from the FUGIN survey, indicate that the components withτ≲1 correspond to diffuse clouds or cloud outer edges. Simultaneous multiple-Gaussian fitting of COJ= 1–0 andJ= 2–1 absorption lines shows that these are composed of narrow- and broad-line components. The kinetic temperature empirically expected from the high HCN/HNC isomer ratio (≳4) reaches ≳40 K and the corresponding thermal width accounts for the line widths of the narrow-line components. CN-bearing molecules and hydrocarbons have tight and linear correlations within the groups. The CO/HCO⁺abundance ratio showed a dispersion as large as 3 orders of magnitude with a smaller ratio in a smallerN(HCO⁺) (or lowerA_V) range. Some of the velocity components are detected in single-dish CO emission and ALMA HCO⁺absorption but without corresponding ALMA CO absorption. This may be explained by the mixture of clumpy CO emitters not resolved with the ∼1 pc single-dish beam surrounded by extended components with a very low CO/HCO⁺abundance ratio (i.e., CO-poor gas). 

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4. VT‐NMR Analysis of Rotation‐Inversion of N ‐(4‐hydroxybutyl)‐ N ‐(2,2,2‐trifluoroethyl) tert ‐butyl Carbamate: Utilizing the −CH ₂ CF ₃ Appendage as a Reporter on E / Z ‐Isomerization

   https://doi.org/10.1002/slct.202401323  

   Jameson, Brian; Glaser, Rainer (April 2024, ChemistrySelect)

   Abstract The rotational barrier about the CN carbamate bond ofN‐(4‐hydroxybutyl)‐N‐(2,2,2‐trifluoroethyl)tert‐butyl carbamate1was determined by variable temperature (VT)¹³C and¹⁹F NMR spectroscopy. The −CH₂CF₃ appendage reports on rotational isomerism and allows for the observation of separate signals for the E‐ and Z‐ensembles at low temperature. The activation barrier for E/Z‐isomerization was quantified using Eyring‐Polanyi theory which requires the measurements of the maximum difference in Larmor frequency Δν_max and the convergence temperature T_c. Both Δν_max and T_c were interpolated by analyzing sigmoidal functions fitted to data describing signal separation and the quality of the superposition of the E‐ and Z‐signals, respectively. Methods for generating the quality‐of‐fit parameters for Lorentzian line shape analysis are discussed. Our best experimental value for the rotational barrier ΔG_c^≠(1)=15.65±0.13 kcal/mol is compared to results of a higher level ab initio study of the modelN‐ethyl‐N‐(2,2,2‐trifluoroethyl) methyl carbamate. 

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5. High‐resolution dataset of stable carbon isotope of dissolved inorganic carbon ( δ¹³C ‐ DIC ) from the North Atlantic Ocean

   https://doi.org/10.1002/lol2.70038  

   Sun, Zhentao; Gao, Hui; Dong, Bo; Hussain, Najid; Atekwana, Eliot A; Cai, Wei‐Jun (September 2025, Limnology and Oceanography Letters)

   Abstract The stable isotope ratio of dissolved inorganic carbon (δ¹³C‐DIC) is a valuable tracer for investigating carbon cycling in aquatic environments. However, its potential remains underutilized due to limited data availability. Fewer than 15% of cruise samples are analyzed forδ¹³C‐DIC, as isotope analysis using isotope ratio mass spectrometry is labor‐intensive and restricted to onshore laboratories. We present over 3500δ¹³C‐DIC measurements from the 2023 Global Ocean Ship‐based Hydrographic Investigations Program A16N cruise in the North Atlantic. Notably, three‐quarters of these measurements were conducted onboard using a CO₂extraction device coupled with cavity ring‐down spectroscopy, a more efficient and cost‐effective method. This extensive dataset providesδ¹³C‐DIC values with spatial resolution comparable to other ocean carbonate chemistry and biogeochemical parameters. This dataset supports improved quantification of anthropogenic CO₂uptake and storage, and may facilitate the development of algorithms to estimateδ¹³C‐DIC in under sampled regions. 

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