Variability in the stellar wind of 68 Cygni - not ‘shells‘ or ‘puffs‘, but streams

Title:

Variability in the stellar wind of 68 Cygni - not ‘shells‘ or ‘puffs‘, but streams

Creator:

Prinja, Raman K. and Howarth, Ian D.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:d82d418e-4305-4b32-9f7b-70280078a342
uuid:d82d418e-4305-4b32-9f7b-70280078a342

Subject:

space research, stellar wind, and streams

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

Results are presented from a study of variability in the stellar wind of G8 Cygni [07.5 III((f))], based on 33 lUE high resolution spectra taken over ~ 7 days. Significant changes are evident in the Si IV resonance line profiles on timescales as short as ~ 1 hour, cliaracterised by broad absorption enhancements at relatively low velocity (0.5 to 0.7 of the terminal velocity, υ∞) which evolve into high velocity discrete absorption components (at > 0.8 over a period of ~ 1 day. The recurrence timescale for the appearance of the broad features is ~ 15-20 hours. Three well monitored consecutive sequenccs of progressive opacity enhancements are described. Their properties are parameterised and incorporated into a self-consistent phenomenological model where the opacity enhancements and ‘underlying’ wind sure radiatively coupled. The model results show that the absorption enhancements do not propagate from the photosphere in any simple way, and are not due to spherically symmetric phenomena. We conclude that the discrete absorption variability in G8 Cyg is not due to ‘shells’ or ‘puffs’ of matter, but instcaid arise from material passing through perturbations in the flow, which may be illustrated in terms of spirally wound-up streams.

Language:

Czech

Rights:

http://creativecommons.org/publicdomain/mark/1.0/
policy:public

Coverage:

39-43

Source:

Publications of the Astronomical Institute of the Academy of Sciences of the Czech Republic | 1987 Volume:63-70 | Number:70

Harvested from:

CDK

Metadata only:

false