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Comets spend most of their lives at large distances from any star, during which time their interior compositions remain relatively unaltered. Cometary observations can therefore provide direct insight into the chemistry that occurred during their birth at the time of planet formation. To-date, there have been no confirmed observations of parent volatiles (gases released directly from the nucleus) of a comet from any planetary system other than our own. Here we present high-resolution, interferometric observations of 2I/Borisov, the first confirmed interstellar comet, obtained using the Atacama Large Millimeter/ submillimeter Array (ALMA) on 15th-16th December 2019. Our observations reveal emission from hydrogen cyanide (HCN), and carbon monoxide (CO), coincident with the expected position of 2I/Borisov’s nucleus, with production rates Q(HCN) = (7.0 ± 1.1) x 10(exp 23)/s and Q(CO) = (4.4 ± 0.7) x 10(exp 26)/s. While the HCN abundance relative to water (0.06–0.16%) appears similar to that of typical, previously observed comets in our Solar System, the abundance of CO (35–105%) is among the highest observed in any comet within 2 au of the Sun. This shows that 2I/Borisov must have formed in a relatively CO-rich environment — probably beyond the CO ice-line in the very cold, outer regions of a distant protoplanetary accretion disk, as part of a population of small, icy bodies analogous to our Solar System’s own proto-Kuiper Belt.

We have observed emission from both ortho and para spin states of ketene (CH sub(2)CO) towards several deeply-embedded protostars. The low CH sub(2)CO fractional abundances (10 super(-10)) and the rotation temperatures (20K) are consistent with emission from the cooler envelope. We compare our results with previous studies and discuss possible production pathways to interstellar ketene. We suggest that, if low observed excitation temperatures of CH sub(2)CO, CH sub(3)CHO and H sub(2)CO are indicative of their absence from the hot core region, then this may be due to the extensive hydrogenation of pre-existing grain mantles prior to evaporation into the inner envelope, leading to lower abundances of these compounds and to mantles rich in alcohols.

The Atacama Large Millimeter/submillimeter Array (ALMA) was used to obtain measurements of spatially and spectrally resolved CH3OH emission from comet C/2012 K1 (PanSTARRS) on 28-29 June 2014. Detection of 12-14 emission lines of CH3OH on each day permitted the derivation of spatially-resolved rotational temperature profiles (averaged along the line of sight), for the innermost 5000 km of the coma. On each day, the CH3OH distribution was centrally peaked and approximately consistent with spherically symmetric, uniform outflow. The azimuthally-averaged CH3OH rotational temperature (T rot) as a function of sky-projected nucleocentric distance (ρ), fell by about 40 K between ρ= 0 and 2500 km on 28 June, whereas on 29 June, T rot fell by about 50 K between ρ =0 km and 1500 km. A remarkable (~50 K) rise in T rot at ρ = 1500-2500 km on 29 June was not present on 28 June. The observed variations in CH3OH rotational temperature are interpreted primarily as a result of variations in the coma kinetic temperature due to adiabatic cooling, and heating through Solar irradiation, but collisional and radiative non-LTE excitation processes also play a role.

Isotopic measurements of Solar System bodies provide a primary paradigm within which to understand the origins and histories of planetary materials. The D/H ratio in particular, helps reveal the relationship between (and heritage of) different H\\(_2\\)O reservoirs within the Solar System. Here we present interferometric maps of water (H\\(_2\\)O) and semiheavy water (HDO) in the gas-phase coma of a comet (Halley-type comet 12P/Pons-Brooks), obtained using the Atacama Large Millimeter/submillimeter Array (ALMA). The maps are consistent with outgassing of both H\\(_2\\)O and HDO directly from the nucleus, and imply a coma D/H ratio (for water) of \\((1.71 \\pm 0.44)\\times10^{-4}\\). This is at the lower end of the range of previously-observed values in comets, and is consistent with D/H in Earth's ocean water. Our results suggest a possible common heritage between a component of the Oort cloud's water ice reservoir, and the water that was delivered to the young Earth during the early history of the Solar System.

Currently, natural fillers seem to be the suitable materials in polymer industry, which have emerged as a viable and abundant replacement for the relatively high-cost and non-renewable conventional fillers. However, the direct introduction of natural fillers into polymer matrix could effect negatively on some properties. Therefore, the aim of this work is to evaluate the influence of jackfruit seed flour (JFSF) (before and after compatibilization) on the tensile properties of (LDPE/JFSF) blends. Different JFSF content (5, 10, 15 and 20 wt.%) with (63-100 ) particle size were prepared in this work. Twin-screw extruder at 150°C and 50rpm screw speed followed by hot-compress machine at 150°C and 10MPa pressure were used respectively to produce (LDPE/JFSF) blends. Adipic acid (AA) solution was added as a compatibilizer into all blends equally (25wt% AA into 75wt% JFSf). The changes of tensile and morphological properties were investigated. Results shown decreasing on tensile strength and elongation at break of LDPE/JFSF and LDPE/JFSF/AA as JFSF increased. In contrast, Young’s modulus increased up to 10 wt.% of JFSF and then decreased. However, the addition of Adipic acid, particularly for JFSF 5wt.% has improved the tensile properties of LDPE/JFSF blends. The SEM micrographs showed the agglomeration at high JFSF content (20 wt%) which in turn effected negatively on the tensile properties. However, the blends show homogeneous surfaces as AA added.

The coma of comet C/2016 R2 (PanSTARRS) is one of the most chemically peculiar ever observed, in particular due to its extremely high CO/H2O and N2+/H2O ratios}, and unusual trace volatile abundances. However, the complex shape of its CO emission lines, as well as uncertainties in the coma structure and excitation, has lead to ambiguities in the total CO production rate. We performed high resolution, spatially, spectrally and temporally resolved CO observations using the James Clerk Maxwell Telescope (JCMT) and Submillimeter Array (SMA) to elucidate the outgassing behaviour of C/2016 R2. Results are analyzed using a new, time-dependent, three dimensional radiative transfer code (SUBLIME), incorporating for the first time, accurate state-to-state collisional rate coefficients for the CO--CO system. The total CO production rate was found to be in the range \\((3.8-7.6)\\times10^{28}\\) s\\(^{-1}\\) between 2018-01-13 and 2018-02-01, with a mean value of \\((5.3\\pm0.6)\\times10^{28}\\) s\\(^{-1}\\) at r_H = 2.8-2.9 au. The emission is concentrated in a near-sunward jet, with an outflow velocity \\(0.51\\pm0.01\\) km/s, compared to \\(0.25\\pm0.01\\) km/s in the ambient (and night-side) coma. Evidence was also found for an extended source of CO emission, possibly due to icy grain sublimation around \\(1.2\\times10^5\\) km from the nucleus. Based on the coma molecular abundances, we propose that the nucleus ices of C/2016 R2 can be divided into a rapidly sublimating apolar phase, rich in CO, CO2, N2 and CH3OH, and a predominantly frozen (or less abundant), polar phase containing more H2O, CH4, H2CO and HCN.

Comets spend most of their lives at large distances from any star, during which time their interior compositions remain relatively unaltered. Cometary observations can therefore provide direct insight into the chemistry that occurred during their birth at the time of planet formation. To-date, there have been no confirmed observations of parent volatiles (gases released directly from the nucleus) of a comet from any planetary system other than our own. Here we present high-resolution, interferometric observations of 2I/Borisov, the first confirmed interstellar comet, obtained using the Atacama Large Millimeter/submillimeter Array (ALMA) on 15th-16th December 2019. Our observations reveal emission from hydrogen cyanide (HCN), and carbon monoxide (CO), coincident with the expected position of 2I/Borisov's nucleus, with production rates Q(HCN)=\\((7.0\\pm1.1)\\times10^{23}\\) s\\(^{-1}\\) and Q(CO)=\\((4.4\\pm0.7)\\times10^{26}\\) s\\(^{-1}\\). While the HCN abundance relative to water (0.06-0.16%) appears similar to that of typical, previously observed comets in our Solar System, the abundance of CO (35-105%) is among the highest observed in any comet within 2 au of the Sun. This shows that 2I/Borisov must have formed in a relatively CO-rich environment - probably beyond the CO ice-line in the very cold, outer regions of a distant protoplanetary accretion disk, as part of a population of small, icy bodies analogous to our Solar System's own proto-Kuiper Belt.

The 100 m Robert C. Byrd Green Bank Telescope K-band (KFPA) receiver was used to perform a high-sensitivity search for rotational emission lines from complex organic molecules in the cold interstellar medium towards TMC-1 (cyanopolyyne peak), focussing on the identification of new carbon-chain-bearing species as well as molecules of possible prebiotic relevance. We report a detection of the carbon-chain oxide species HC\\(_7\\)O and derive a column density of \\((7.8\\pm0.9)\\times10^{11}\\)~cm\\(^{-2}\\). This species is theorized to form as a result of associative electron detachment reactions between oxygen atoms and C\\(_7\\)H\\(^-\\), and/or reaction of C\\(_6\\)H$_2$$^+\\( with CO (followed by dissociative electron recombination). Upper limits are given for the related HC\\)_6\\(O, C\\)_6\\(O and C\\)_7\\(O molecules. In addition, we obtained the first detections of emission from individual \\)^{13}\\(C isotopologues of HC\\)_7\\(N, and derive abundance ratios HC\\)_7\\(N/HCCC\\)^{13}\\(CCCCN = \\)110\\pm16\\( and HC\\)_7\\(N/HCCCC\\)^{13}\\(CCCN = \\)96\\pm 11\\(, indicative of significant \\)^{13}\\(C depletion in this species relative to the local interstellar elemental \\)^{12}\\(C/\\)^{13}\\(C ratio of 60-70. The observed spectral region covered two transitions of HC\\)_{11}\\(N, but emission from this species was not detected, and the corresponding column density upper limit is \\)7.4\\times10^{10}\\( cm\\)^{-2}\\( (at 95% confidence). This is significantly lower than the value of \\)2.8\\times10^{11}\\( cm\\)^{-2}\\( previously claimed by Bell et al. (1997) and confirms the recent non-detection of HC\\)_{11}$N in TMC-1 by Loomis et al. (2016). Upper limits were also obtained for the column densities of malononitrile and the nitrogen heterocycles quinoline, isoquinoline and pyrimidine.

Observations of the sungrazing comet C/2012 S1 (ISON) were carried out using the Atacama Large Millimeter/submillimeter Array (ALMA) at a heliocentric distance of 0.58-0.54 AU (pre-perihelion) on 2013 November 16-17. Temporally resolved measurements of the coma distributions of HNC, CH\\(_3\\)OH, H\\(_2\\)CO and dust were obtained over the course of about an hour on each day. During the period UT 10:10-11:00 on Nov. 16, the comet displayed a remarkable drop in activity, manifested as a \\(>42\\)% decline in the molecular line and continuum fluxes. The H\\(_2\\)CO observations are consistent with an abrupt, \\(\\approx50\\)% reduction in the cometary gas production rate soon after the start of our observations. On Nov. 17, the total observed fluxes remained relatively constant during a similar period, but strong variations in the morphology of the HNC distribution were detected as a function of time, indicative of a clumpy, intermittent outflow for this species. Our observations suggest that at least part of the detected HNC originated from degradation of nitrogen-rich organic refractory material, released intermittently from confined regions of the nucleus. By contrast, the distributions of CH\\(_3\\)OH and H\\(_2\\)CO during the Nov. 17 observations were relatively uniform, consistent with isotropic outflow and stable activity levels for these species. These results highlight a large degree of variability in the production of gas and dust from comet ISON during its pre-perihelion outburst, consistent with repeated disruption of the nucleus interspersed with periods of relative quiescence.

We present spatially and spectrally-resolved observations of CH\\(_3\\)OH emission from comet C/2012 K1 (PanSTARRS) using The Atacama Large Millimeter/submillimeter Array (ALMA) on 2014 June 28-29. Two-dimensional maps of the line-of-sight average rotational temperature (\\(T_{rot}\\)) were derived, covering spatial scales \\(0.3''-1.8''\\) (corresponding to sky-projected distances \\(\\rho\\sim500\\)-2500 km). The CH\\(_3\\)OH column density distributions are consistent with isotropic, uniform outflow from the nucleus, with no evidence for extended sources of CH\\(_3\\)OH in the coma. The \\(T_{rot}(\\rho)\\) radial profiles show a significant drop within a few thousand kilometers of the nucleus, falling from about 60 K to 20 K between \\(\\rho=0\\) and 2500 km on June 28, whereas on June 29, \\(T_{rot}\\) fell from about 120 K to 40 K between \\(\\rho=\\) 0 km and 1000 km. The observed \\(T_{rot}\\) behavior is interpreted primarily as a result of variations in the coma kinetic temperature due to adiabatic cooling of the outflowing gas, as well as radiative cooling of the CH\\(_3\\)OH rotational levels. Our excitation model shows that radiative cooling is more important for the \\(J=7-6\\) transitions (at 338 GHz) than for the \\(K=3-2\\) transitions (at 252 GHz), resulting in a strongly sub-thermal distribution of levels in the \\(J=7-6\\) band at \\(\\rho\\gtrsim1000\\) km. For both bands, the observed temperature drop with distance is less steep than predicted by standard coma theoretical models, which suggests the presence of a significant source of heating in addition to the photolytic heat sources usually considered.