Haswell, Carole A.; Robinson, Edward L.; Horne, Keith; Stiening, Rae F. and Abbott, Timothy M.C.
On the mass of the compact object in the black hole binary A0620-00.
Astrophysical Journal, 411(2),
Multicolor orbital light curves of the black hole candidate binary A0620-00 are presented. The light curves exhibit ellipsoidal variations and a grazing eclipse of the mass donor companion star by the accretion disk. Synthetic light curves were generated using realistic mass donor star fluxes and an isothermal blackbody disk. For mass ratios of q = M1/M sub 2 = 5.0, 10.6, and 15.0 systematic searches were executed in parameter space for synthetic light curves that fit the observations. For each mass ratio, acceptable fits were found only for a small range of orbital inclinations. It is argued that the mass ratio is unlikely to exceed q = 10.6, and an upper limit of 0.8 solar masses is placed on the mass of the companion star. These constraints imply 4.16 +/- 0.1 to 5.55 +/- 0.15 solar masses. The lower limit on M1 is more than 4-sigma above the mass of a maximally rotating neutron star, and constitutes further strong evidence in favor of a black hole primary in this system.
|| BINARY STARS, BLACK HOLES (ASTRONOMY), COMPANION STARS, LIGHT CURVE, NEUTRON STARS, STELLAR MASS, DWARF STARS, SKY SURVEYS (ASTRONOMY), STELLAR GRAVITATION, STELLAR ROTATION
||Science > Physical Sciences
|Interdisciplinary Research Centre:
||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
||28 Jul 2008 09:32
||02 Dec 2010 20:09
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