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The Unusual S Star Binary HD 191589Recently, we discovered with International Ultraviolet Explorer (IUE) an F0-F2 IV-V companion to the T(sub c)-deficient S star HD 191589. If the magnitude difference is (delta)V=3.7, as indicated by several arguments, and E(B-V) = 0.0, we obtain a value of M(sub v)= - 1.5 +/- 0.4 for the Peculiar Red Giant (PRG), too faint for it to be a thermally-pulsing asymptotic giant branch star. According to the binary mass-transfer hypothesis for T(sub c)-deficient PRG's, a white dwarf must be the source of the s-process enhancement of the current primary star, but it cannot be seen because of the presence of the secondary. If such is the case, the F-star companion may also have been contaminated by s-process material. High-dispersion IUE observations indicate an enhancement of Zr II in the photosphere of the F-star as well. Thus, HD 191589 is likely a triple system, where what was once the most massive component of the system has polluted both of its companions with s-process material. One of these is the current S star, while the other is the companion still near the main sequence.
Document ID
19970011566
Acquisition Source
Goddard Space Flight Center
Document Type
Contractor Report (CR)
Authors
Ake, Thomas B. (Computer Sciences Corp. Greenbelt, MD United States)
Johnson, Hollis R. (Indiana Univ. Bloomington, IN United States)
Wahlgren, Glenn M. (Computer Sciences Corp. Greenbelt, MD United States)
Jorissen, Alain (Brussels Univ. Belgium)
Date Acquired
September 6, 2013
Publication Date
July 1, 1996
Subject Category
Astrophysics
Report/Patent Number
Rept-4124
NAS 1.26:203625
NASA-CR-203625
Accession Number
97N16435
Funding Number(s)
CONTRACT_GRANT: NAS5-182
CONTRACT_GRANT: NASA Order S-30912-F
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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