κ Velorum: Another variable interstellar sightline?
Monthly Notices of the Royal Astronomical Society
L1 - L6.
We present ultra-high-resolution (R = 900 000) observations of interstellar Na i and K i absorption lines towards κ Vel (HD 81188) which show clear evidence for temporal variation between 1994 and 2000. Specifically, the column densities of K0 and Na0 in the main velocity component have increased by 40 and 16 per cent, respectively, over this period. Earlier work had suggested that this component actually consists of two unresolved sub-components; this result is confirmed here, and the overall line profile is found to be consistent with only one of these sub-components having increased in strength since 1994. We argue that this variation is consistent with the line of sight gradually probing a cold, dense interstellar filament of the kind recently proposed by Heiles to explain other observations of small-scale structure in the interstellar medium.
|Title:||κ Velorum: Another variable interstellar sightline?|
|Open access status:||An open access version is available from UCL Discovery|
|Additional information:||© 2000 RAS Definitive versions of articles pre-2013 are available at http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2966, now published by http://mnras.oxfordjournals.org|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Physics and Astronomy|
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