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On the absence of young white dwarf companions to five technetium starsA search for hot companions to five stars of type MS and S has been carried out using the IUE satellite. No hot companions were detected for the MS stars HR 85, 4647, 6702, and 8062, and the S star HR 8714. Limits on the luminosities of possible white dwarf companions provide lower limits of 2-5x10 to the 8th yr to the ages of any degenerate companions. All five stars exhibit strong Tc I lines, and the presence of technetium, with a half-life of 2.1x10 to the 5th yr, signifies recent nucleosynthesis. The limits on the ages of possible white dwarf companions that are equal to or greater than 1000 half-lives of Tc exclude the possibility that the s-process elemental enhancement seen in these MS and S stars resulted from mass transfer from a more highly evolved companion (as is probably the mechanism by which barium stars are created). These MS and S stars represent a sample of true thermally pulsing asymptotic giant-branch stars.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Smith, Verne V.
(Texas Univ. Austin, TX, United States)
Lambert, David L.
(Texas, University; McDonald Observatory, Austin, United States)
Date Acquired
August 13, 2013
Publication Date
October 1, 1987
Publication Information
Publication: Astronomical Journal
Volume: 94
ISSN: 0004-6256
Subject Category
Accession Number
Funding Number(s)
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