Stars Orbiting the Milky Way's Black Hole

Image Source: http://www.astro.ucla.edu/~ghezgroup/gc/research/S02_S0102_orbits.html

The orbits of stars within the central arcsecond of our Galaxy. In the background, the central portion of a diffraction-limited image taken in 2012 is displayed. The orbits have been inferred from images taken with the primitive technique of speckle imaging (1995 - 2005) and with the more sophisticated adaptive optics (2005-2012). While several stars can be seen in their motion through this region, only two stars - S0-2 and the newly discovered S0-102 - have been traced through a complete orbit. They are the most tightly bound to the black hole and therefore comprise the most information about it. S0-2, which has an orbital period of 16 years, proved the existence of a black hole. The addition of S0-102, with a period of 11.5 years, will for the first time allow us to test the warping of space and time this close to a black hole. Stars that have been observed through at least one turning point in their orbit are shown in blue.