Picture of a black hole

Strathclyde Open Access research that creates ripples...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of research papers by University of Strathclyde researchers, including by Strathclyde physicists involved in observing gravitational waves and black hole mergers as part of the Laser Interferometer Gravitational-Wave Observatory (LIGO) - but also other internationally significant research from the Department of Physics. Discover why Strathclyde's physics research is making ripples...

Strathprints also exposes world leading research from the Faculties of Science, Engineering, Humanities & Social Sciences, and from the Strathclyde Business School.

Discover more...

A 3-5 mu m VLT spectroscopic survey of embedded young low mass stars II - Solid OCN-

van Broekhuizen, F A and Pontoppidan, K M and Fraser, H J and van Dishoeck, E F (2005) A 3-5 mu m VLT spectroscopic survey of embedded young low mass stars II - Solid OCN-. Astronomy and Astrophysics, 441 (1). pp. 249-260. ISSN 0004-6361

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

The 4.62 mu m (2164.5 cm(-1)) "XCN" band has been detected in the M-band spectra of 34 deeply embedded young stellar objects (YSO's), observed with high signal-to-noise and high spectral resolution with the VLT-ISAAC spectrometer, providing the first opportunity to study the solid OCN- abundance toward a large number of low-mass YSO's. It is shown unequivocally that at least two components, centred at 2165.7 cm(-1) (FWHM=26 cm(-1)) and 2175.4 cm(-1) (FWHM=15 cm(-1)), underlie the XCN band. Only the 2165.7-component can be ascribed to OCN-, embedded in a strongly hydrogen-bonding, and possibly thermally annealed, ice environment based on laboratory OCN- spectra. In order to correct for the contribution of the 2175.4-component to the XCN band, a phenomenological decomposition into the 2165.7- and the 2175.4-components is used to fit the full band profile and derive the OCN- abundance for each line-of-sight. The same analysis is performed for 5 high-mass YSO's taken from the ISO-SWS data archive. Inferred OCN- abundances are <= 0.85% toward low-mass YSO's and <= 1% toward high-mass YSO's, except for W33A. Abundances are found to vary by at least a factor of 10-20 and large source-to-source abundance variations are observed within the same star-forming cloud complex on scales down to 400 AU, indicating that the OCN- formation mechanism is sensitive to local conditions. The inferred abundances allow quantitatively for photochemical formation of OCN-, but the large abundance variations are not easily explained in this scenario unless local radiation sources or special geometries are invoked. Surface chemistry should therefore be considered as an alternative formation mechanism.