THE EFFECT OF STARSPOTS ON ACCURATE RADIUS DETERMINATION OF THE LOW-MASS DOUBLE-LINED ECLIPSING BINARY GU Boo
GU Boo is one of only a relatively small number of well-studied double-lined eclipsing binaries that contain low-mass stars. Lopez-Morales and Ribas present a comprehensive analysis of multi-color light and radial velocity curves for this system. The GU Boo light curves presented by Lopez-Morales and Ribas had substantial asymmetries, which were attributed to large spots. In spite of the asymmetry, Lopez-Morales and Ribas derived masses and radii accurate to {approx_equal}2%. We obtained additional photometry of GU Boo using both a CCD and a single-channel photometer and modeled the light curves with the ELC software to determine if the large spots in the light curves give rise to systematic errors at the few percent level. We also modeled the original light curves from the work of Lopez-Morales and Ribas using models with and without spots. We derived a radius of the primary of 0.6329 +- 0.0026 R{sub sun}, 0.6413 +- 0.0049 R{sub sun}, and 0.6373 +- 0.0029 R{sub sun} from the CCD, photoelectric, and Lopez-Morales and Ribas data, respectively. Each of these measurements agrees with the value reported by Lopez-Morales and Ribas (R{sub 1} = 0.623 +- 0.016 R{sub sun}) at the level of {approx}2%. In addition, the spread in these values is {approx}1%-2% from the mean. For the secondary, we derive radii of 0.6074 +- 0.0035 R{sub sun}, 0.5944 +- 0.0069 R{sub sun}, and 0.5976 +- 0.0059 R{sub sun} from the three respective data sets. The Lopez-Morales and Ribas value is R{sub 2} = 0.620 +- 0.020 R{sub sun}, which is {approx}2%-3% larger than each of the three values we found. The spread in these values is {approx}2% from the mean. The systematic difference between our three determinations of the secondary radius and that of Lopez-Morales and Ribas might be attributed to differences in the modeling process and codes used. Our own fits suggest that, for GU Boo at least, using accurate spot modeling of a single set of multi-color light curves results in radii determinations accurate at the {approx}2% level.
- OSTI ID:
- 21394205
- Journal Information:
- Astrophysical Journal, Vol. 712, Issue 2; Other Information: DOI: 10.1088/0004-637X/712/2/1003; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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