ON THE AGE OF GLIESE 86

Gliese 86 is a nearby planet hosting a visual binary consisting of a K-type primary, G1 86 A, and a white dwarf secondary, G1 86 B. In this work, we present a model atmosphere analysis of the M sub(A) = 0.83 M sub([middot in circle]) primary, whose chemistry unambiguously identifies it as a 10 Gyr o...

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Bibliographic Details
Published in:The Astrophysical journal 2014-04, Vol.785 (1), p.1-4, Article 68
Main Authors: Fuhrmann, K, Chini, R, Buda, L-S, Nunez, F Pozo
Format: Article
Language:English
Subjects:
Accretion
Age
ANGULAR MOMENTUM
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
ATMOSPHERES
BINARY STARS
Disks
MASS TRANSFER
PLANETARY NEBULAE
PLANETS
Procyon
Progenitors (astrophysics)
STELLAR WINDS
Visual
WHITE DWARF STARS
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Summary:Gliese 86 is a nearby planet hosting a visual binary consisting of a K-type primary, G1 86 A, and a white dwarf secondary, G1 86 B. In this work, we present a model atmosphere analysis of the M sub(A) = 0.83 M sub([middot in circle]) primary, whose chemistry unambiguously identifies it as a 10 Gyr old disk star. For the secondary, this gives rise to a progenitor mass M sub(prog) = 1.11 + or - 0.05 M sub([middot in circle]), and-by inference with its local sibling o super(2) Eri-a white dwarf mass M sub(B) = 0.49 + or - 0.02 M sub([middot in circle]). The discrepancy with the 2-3 Gyr chromospheric age of G1 86 A, as first noted by Rocha-Pinto, Castilho & Maciel, is thus most plausibly the result of a former accretion of mass and angular momentum from the distant degenerate. In consequence, this also implies that with respect to shorter-period systems, like Sirius or Procyon, one must expect significant wind accretion when they evolve through the planetary nebula phase, such that the system ages cannot be reliably determined from their currently bright primaries.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/785/1/68