相关论文: CO and N2 Produced from H2O, CO2, and NH3 Cometary…
Complex organic molecules (COMs) can be produced by energetic processing of interstellar ice mantles accreted on top of dust grains. Two COMs with proposed energetic ice formation pathways are formamide and acetaldehyde. Both have been…
CO2 ice is one of the most abundant components in ice-coated interstellar ices besides H2O and CO, but the most favorable path to CO2 ice is still unclear. Molecular dynamics calculations on the ultraviolet photodissociation of different…
CO and CO$_2$ are the two dominant carbon-bearing molecules in comae and have major roles in driving activity. Their relative abundances also provide strong observational constraints to models of solar system formation and evolution but…
To date, at least three comets -- 2I/Borisov, C/2016 R2 (PanSTARRS), and C/2009 P1 (Garradd) -- have been observed to have unusually high CO concentrations compared to water. We attempt to explain these observations by modeling the effect…
Solid state astrochemical reaction pathways have the potential to link the formation of small nitrogen-bearing species, like NH3 and HNCO, and prebiotic molecules, specifically amino acids. To date, the chemical origin of such small…
Remote and in-situ observations of cometary gases have revealed the presence of a wealth of complex organic molecules, including carbon chains, alcohols, imines and the amino acid glycine. Such chemical complexity in cometary material…
Recent observations of the long period comet C/2016 R2 (PanSTARRS) indicate an unusually high N2/CO abundance ratio, typically larger than 0.05, and at least 2-3 times higher than the one measured in 67P/Churyumov-Gerasimenko. Another…
Based on the occurrence rates implied by the discoveries of 1I/`Oumuamua and 2I/Borisov, the forthcoming Rubin Observatory Legacy Survey of Space and Time (LSST) should detect $\ge1$ interstellar objects every year (Hoover et al. 2021). We…
Ice chemistry in the dense, cold interstellar medium (ISM) is probably responsible for the formation of interstellar complex organic molecules (COMs). Recent laboratory experiments performed at T=4 K have shown that irradiation of CO:N2 ice…
In dense clouds of the interstellar medium, dust grains are covered by ice mantles, dominated by H$_2$O. CO and CO$_2$ are common ice components observed in infrared spectra, while infrared inactive N$_2$ is expected to be present in the…
Comet C/2017 K2 (Pan-STARRS) provided a rare opportunity to investigate the evolution of coma composition and outgassing patterns over a transitional heliocentric distance (Rh) range where activity drivers in comets are thought to change…
Comets have similar compositions to interstellar medium ices, suggesting at least some of their molecules maybe inherited from an earlier stage of evolution. To investigate the degree to which this might have occurred we compare the…
The composition of cometary ices provides key information on the thermal and chemical properties of the outer parts of the protoplanetary disk where they formed 4.6 Gy ago. This chapter reviews our knowledge of composition of cometary comae…
Hyperactive comet activity typically becomes evident beyond the frost line (3 to 4 au) where it becomes too cold for water-ice to sublimate. If carbon monoxide (CO) and carbon dioxide (CO2) are the species that drive activity at…
The astronomical detection of formamide (NH$_2$CHO) toward various star-forming regions and in cometary material implies that the simplest amide might have an early origin in dark molecular clouds at low temperatures. Laboratory studies…
Planet atmosphere and hydrosphere compositions are fundamentally set by accretion of volatiles, and therefore by the division of volatiles between gas and solids in planet-forming disks. For hyper-volatiles such as CO, this division is…
Comet C/2016 R2 (PanSTARRS) has a peculiar volatile composition, with CO being the dominant volatile as opposed to H$_2$O and one of the largest N$_2$/CO ratios ever observed in a comet. Using observations obtained with the \textit{Spitzer…
Icy interstellar dust grains are a source of complex organic molecule (COM) production, although their formation mechanisms are debated. Laboratory experiments show that atomic C deposited onto interstellar ice analogs can react with…
The solid-state C$_2$H$_2$ chemistry in interstellar H$_2$O-rich ice has been proposed to explain astronomically observed complex organic molecules (COMs), including ketene (CH$_2$CO), acetaldehyde (CH$_3$CHO), and ethanol (CH$_3$CH$_2$OH),…
Starless molecular cores are natural laboratories for interstellar molecular chemistry research. The chemistry of ices in such objects was investigated with a three-phase (gas, surface, and mantle) model. We considered the center part of…