SIMBAD references

2014AJ....147...36T - Astron. J., 147, 36 (2014/February-0)

Absolute properties of the eclipsing binary system AQ Serpentis: a stringent test of convective core overshooting in stellar evolution models.


Abstract (from CDS):

We report differential photometric observations and radial-velocity measurements of the detached, 1.69 day period, double-lined eclipsing binary AQ Ser. Accurate masses and radii for the components are determined to better than 1.8% and 1.1%, respectively, and are M1= 1.417±0.021 M, M2= 1.346±0.024 M, R1= 2.451±0.027 R, and R2= 2.281±0.014 R. The temperatures are 6340±100 K (spectral type F6) and 6430±100 K (F5), respectively. Both stars are considerably evolved, such that predictions from stellar evolution theory are particularly sensitive to the degree of extra mixing above the convective core (overshoot). The component masses are different enough to exclude a location in the H-R diagram past the point of central hydrogen exhaustion, which implies the need for extra mixing. Moreover, we find that current main-sequence models are unable to match the observed properties at a single age even when allowing the unknown metallicity, mixing length parameter, and convective overshooting parameter to vary freely and independently for the two components. The age of the more massive star appears systematically younger. AQ Ser and other similarly evolved eclipsing binaries showing the same discrepancy highlight an outstanding and largely overlooked problem with the description of overshooting in current stellar theory.

Abstract Copyright:

Journal keyword(s): binaries: eclipsing - stars: evolution - stars: fundamental parameters

VizieR on-line data: <Available at CDS (J/AJ/147/36): table1.dat table2.dat table3.dat table5.dat>

Simbad objects: 9

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