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Ultraviolet observations of cool stars. V. The local density of interstellar matter

Journal Article · · Astrophys. J., Lett.; (United States)
DOI:https://doi.org/10.1086/182064· OSTI ID:7285759
A high-resolution Copernicus observation of the chromospheric L..cap alpha.. emission line of the nearby (3.3 pc) K dwarf epsilon Eri sets limits on the velocity, the velocity dispersion, and the density n/sub H/ of atomic hydrogen in the local interstellar medium. Analysis shows that the interstellar L..cap alpha.. absorption is on the flat portion of the curve of growth. An upper limit of n/sub H/=0.12 cm/sup -3/od n/sub H/ is 0.08 +- 0.04 cm/sup -3/ if the velocity dispersion parameter b = 9 km s/sup -1/, corresponding to a temperature of 5000 K. Also, the interstellar deuterium L..cap alpha.. line may be present in the spectrum. (AIP)
Research Organization:
Physics Department, The Johns Hopkins University
OSTI ID:
7285759
Journal Information:
Astrophys. J., Lett.; (United States), Journal Name: Astrophys. J., Lett.; (United States) Vol. 204:2; ISSN AJLEA
Country of Publication:
United States
Language:
English