NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
IUE ultraviolet spectra and chromospheric models of HR 1099 and UX ArietisIUE spectra in the region 1150-3200 A of the RS CVn-type variables HR 1099 and UX Arietis are presented and analyzed in terms of chromospheric models. Measurements of Mg h and k lines and Ca II H-K and H alpha spectra are indicated which are found not to be correlated with orbital phase or radio flares and which suggest that the strong emission arises in the K star rather than the G star in these systems. Under the assumption that the UV emission lines are associated with the K star, surface gravities of log g = 3.6 and 3.4 and effective temperatures of 4850 and 5000 K are adopted for HR 1099 and UX Ari, respectively, along with solar metal abundances for each. Model calculations of the chromospheric structure necessary to account for observed C(+), Mg(+), Si(+) and Si(+2) line fluxes are presented which indicate that the transition region pressure lies in the range 0.18-1.0 dynes/sq cm, implying transition regions that are more extended than that of the sun and are not conductively heated. It is noted that pressure scaling laws and the use of Mg II and C II lines as pressure diagnostics may be invalid, possibly due to atmospheric inhomogeneities or gas flows.
Document ID
19810031671
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Simon, T.
(Joint Institute for Laboratory Astrophysics; National Bureau of Standards, Quantum Physics Div., Boulder Colo., United States)
Linsky, J. L.
(Joint Inst. for Lab. Astrophysics Boulder, CO, United States)
Date Acquired
September 4, 2013
Publication Date
October 15, 1980
Publication Information
Publication: Astrophysical Journal
Subject Category
Astrophysics
Report/Patent Number
PB81-163032
Accession Number
81A16075
Funding Number(s)
CONTRACT_GRANT: NAS5-23274
CONTRACT_GRANT: NGL-06-003-057
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available