Ground-based monitoring of comet 67P/Churyumov-Gerasimenko gas activity throughout the <i>Rosetta</i> mission

Simultaneously to the ESA Rosetta mission, a world-wide ground-based campaign provided measurements of the large scale activity of comet 67P/Churyumov-Gerasimenko through measurement of optically active gas species and imaging of the overall dust coma. We present more than two years of observations performed with the FORS2 low resolution spectrograph at the VLT, TRAPPIST, and ACAM at the WHT. We focus on the evolution of the CN production, as a tracer of the comet activity. We find that it is asymmetric with respect to perihelion and different from that of the dust. The CN emission is detected for the first time at 1.34 au pre-perihelion and production rates then increase steeply to peak about two weeks after perihelion at (1.00±0.10) ×1025 molecules s−1, while the post-perihelion decrease is more shallow. The evolution of the comet activity is strongly influenced by seasonal effects, with enhanced CN production when the Southern hemisphere is illuminated

Prevalence of Toxocara canis eggs in dog faeces from public places of Florence, Italy

AbstractTo determine whether canine faecal contamination may represent a source of environmental contamination with Toxocara canis eggs within the urban area of Florence, a total number of 754 dog faeces were collected in 7 public places and examined by routine floatation technique during one-year period. The total prevalence of intestinal nematode eggs was 8.6 %. Trichuris vulpis (4.6 %) eggs were the most prevalent followed by T. canis (3.6 %) and Ancylostomidae (1.7 %) eggs. Mixed infections included T. canis/T. vulpis (0.7 %), Ancylostomidae/T. canis (0.4 %), and Ancylosto-midae/T. vulpis (0.3 %). Total prevalence of intestinal nematode eggs was significantly higher in spring than in winter (OR = 2.06). Our results indicate a low prevalence of T. canis eggs suggesting that dog faeces left on soil are unlikely to cause high environmental contamination with T. canis eggs in the town of Florence

Synthesis, HPLC enantioresolution and X-ray analysis of a new series of C5-methyl pyridazines as N-formyl peptide receptor (FPR) agonists

The synthesis of three racemates and the corresponding non chiral analogues of a C5-methyl pyridazine series is described here, as well as the isolation of pure enantiomers and their absolute configuration assignment. In order to obtain optically active compounds, direct chromatographic methods of separation by HPLC-UV were investigated using four chiral stationary phases (CSPs: Lux Amylose-2(®), Lux Cellulose-1(®), Lux Cellulose-2(®) and Lux Cellulose-3(®)). The best resolution was achieved using amylose tris(5-chloro-2-methylphenylcarbamate) (Lux Amylose-2(®)), and single enantiomers were isolated on a semipreparative scale with high enantiomeric excess, suitable for biological assays. The absolute configuration of optically active compounds was unequivocally established by X-ray crystallographic analysis and comparative chiral HPLC-UV profile. All compounds of the series were tested for formyl peptide receptor (FPR) agonist activity, and four were found to be active, with EC(50) values in the micromolar range

First detection of CO2_2 emission in a Centaur: JWST NIRSpec observations of 39P/Oterma

Centaurs are minor solar system bodies with orbits transitioning between those of Trans-Neptunian Scattered Disk objects and Jupiter Family comets. 39P/Oterma is a frequently active Centaur that has recently held both Centaur and JFC classifications and was observed with the JWST NIRSpec instrument on 2022 July 27 UTC while it was 5.82 au from the Sun. For the first time, CO$_2$ gas emission was detected in a Centaur, with a production rate of Q$_{CO_2}$ = (5.96 $\pm$ 0.80) $\times$ 10$^{23}$ molecules s$^{-1}$. This is the lowest detection of CO$_2$ of any Centaur or comet. CO and H$_2$O were not detected down to constraining upper limits. Derived mixing ratios of Q$_{CO}$/Q$_{CO_2}$ $\leq$2.03 and Q$_{CO_2}$/Q$_{H_2O}$ $\geq$0.60 are consistent with CO$_2$ and/or CO outgassing playing large roles in driving the activity, but not water, and show a significant difference between the coma abundances of 29P/Schwassmann-Wachmann 1, another Centaur at a similar heliocentric distance, which may be explained by thermal processing of 39P's surface during its previous Jupiter-family comet orbit. To help contextualize the JWST data we also acquired visible CCD imaging data on two dates in July (Gemini North) and September (Lowell Discovery Telescope) 2022. Image analysis and photometry based on these data are consistent with a point source detection and an estimated effective nucleus radius of 39P in the range of $R_{nuc}=$2.21 to 2.49~km

JWST molecular mapping and characterization of Enceladus' water plume feeding its torus

Enceladus is a prime target in the search for life in our solar system, having an active plume likely connected to a large liquid water subsurface ocean. Using the sensitive NIRSpec instrument onboard JWST, we searched for organic compounds and characterized the plume's composition and structure. The observations directly sample the fluorescence emissions of H2O and reveal an extraordinarily extensive plume (up to 10,000 km or 40 Enceladus radii) at cryogenic temperatures (25 K) embedded in a large bath of emission originating from Enceladus' torus. Intriguingly, the observed outgassing rate (300 kg/s) is similar to that derived from close-up observations with Cassini 15 years ago, and the torus density is consistent with previous spatially unresolved measurements with Herschel 13 years ago, suggesting that the vigor of gas eruption from Enceladus has been relatively stable over decadal timescales. This level of activity is sufficient to maintain a derived column density of 4.5x1017 m-2 for the embedding equatorial torus, and establishes Enceladus as the prime source of water across the Saturnian system. We performed searches for several non-water gases (CO2, CO, CH4, C2H6, CH3OH), but none were identified in the spectra. On the surface of the trailing hemisphere, we observe strong H2O ice features, including its crystalline form, yet we do not recover CO2, CO nor NH3 ice signatures from these observations. As we prepare to send new spacecraft into the outer solar system, these observations demonstrate the unique ability of JWST in providing critical support to the exploration of distant icy bodies and cryovolcanic plumes.Comment: Accepted for publication in Nature Astronomy on May 17th 202

Detailed Analysis of Near-IR Water (H<SUB>2</SUB>O) Emission in Comet C/2014 Q2 (Lovejoy) with the GIANO/TNG Spectrograph

We observed the Oort cloud comet C/2014 Q2 (Lovejoy) on 2015 January 31 and February 1 and 2 at a heliocentric distance of 1.3 au and geocentric distance of 0.8 au during its approach to the Sun. Comet Lovejoy was observed with GIANO, the near-infrared high-resolution spectrograph mounted at the Nasmyth-A focus of the TNG (Telescopio Nazionale Galileo) telescope in La Palma, Canary Islands, Spain. We detected strong emissions of radical CN and water, along with many emission features of unidentified origin, across the 1-2.5 μm region. Spectral lines from eight ro-vibrational bands of H2O were detected, six of them for the first time. We quantified the water production rate [Q(H2O), (3.11 ± 0.14) × 1029 s-1] by comparing the calibrated line fluxes with the Goddard full non-resonance cascade fluorescence model for H2O. The production rates of ortho-water [Q(H2O)ORTHO, (2.33 ± 0.11) × 1029 s-1] and para-water [Q(H2O)PARA, (0.87 ± 0.21) × 1029 s-1] provide a measure of the ortho-to-para ratio (2.70 ± 0.76)). The confidence limits are not small enough to provide a critical test of the nuclear spin temperature