image: This image shows the geometry and light curve of the KOI-3278 system. As the white dwarf orbits a G dwarf (sun-like star) in this system, when the white dwarf passes in front of the G dwarf, it causes gravitational magnification, resulting in a pulse with a duration of 5 hours and height of 0.1%, while when it passes behind, it is blocked from view, causing an occultation and a dip, also of 0.1% (by coincidence). The black line represents the orbital flux as a function of time, relative to the flux only of the G dwarf (which is shown as a dotted line). This diagram is not to scale, and does not show the stellar variability or noise. For example, the pulse and occultation only last 5 hours out of the 88.2 days of the orbit, while in this diagram they last a much larger fraction of the orbit. This image relates to a paper that appeared in 18 April, 2014, issue of Science, published by AAAS. The paper, by Ethan Kruse1 and Eric Agol at the Perelman School of Medicine at the University of Washington in Seattle, Wash., was titled, "KOI-3278: A Self-Lensing Binary Star System." view more
Credit: [Image courtesy of Eric Agol]