arXiv subjects

S. B. Charnley

Publications and source records attributed to S. B. Charnley.

58 records · Page 4Linked to original sources

arXiv2004

Organic Molecules in Low-Mass Protostellar Hot Cores: Submillimeter Imaging of IRAS 16293-2422

Arcsecond-resolution spectral observations toward the protobinary system IRAS 16293-2422 at 344 and 354 GHz were conducted using the Submillimeter Array. Complex organic molecules such as CH3OH and HCOOCH3 were detected. Together with the rich organic inventory revealed, it clearly indicates the existence of two, rather than one, compact hot molecular cores (smaller than or equal to 400 AU in radius) associated with each of the protobinary components identified by their dust continuum emission in the inner star-forming core.

astro-ph↗

arXiv2002

Chemical Processes in Cometary Comae

Recent developments in the chemical modelling of cometary comae are described. We discuss the cyanide chemistry and present new HCN observations of the recent comet C/2002 C1 (Ikeya-Zhang). The connection between interstellar and cometary organic molecules is discussed from the perspective of recent theories of interstellar gas-grain chemistry.

astro-ph↗

arXiv2001

Biomolecules in the Interstellar Medium and Comets

We review recent studies of organic molecule formation in dense molecular clouds and in comets. We summarise the known organic inventories of molecular clouds and recent comets, particularly Hale-Bopp. The principal chemical formation pathways involving gas phase reactions, as well as formation by catalytic reactions on grain surfaces or through dust fragmentation, are identified for both dense clouds and cometary comae. The processes leading to organic molecules with known biological function, carbon chains, deuterium fractionation, HNC and S-bearing compounds are described. Observational searches for new interstellar organics are outlined and the connection between observed interstellar organics and those detected in comets Hale-Bopp and Hyakutake are discussed.

astro-ph↗

arXiv2001

Gas phase production of NHD2 in L134N

We show analytically that large abundances of NH2D and NHD2 can be produced by gas phase chemistry in the interiors of cold dense clouds. The calculated fractionation ratios are in good agreement with the values that have been previously determined in L134N and suggest that triply-deuterated ammonia could be detectable in dark clouds. Grain surface reactions may lead to similar NH2D and NHD2 enhancements but, we argue, are unlikely to contribute to the deuteration observed in L134N.

astro-ph↗